0000950170-24-036484 | 10-K | XBRL Viewer

Net Loss Per Share

12 Months Ended

Dec. 31, 2023

. Net Loss Per Share

Basic net loss per share is computed by dividing the net loss in each period by the weighted average number of ordinary shares outstanding during such period. Diluted net loss per share is computed similarly to basic net loss per share except that the denominator is increased to include the number of additional ordinary shares that would have been outstanding if the potential ordinary shares had been issued and if the additional ordinary shares were dilutive. For the periods presented, ordinary share equivalents, consisting of share-based awards, were not included in the calculation of the diluted net loss per share because to do so would be anti-dilutive. There were no dilutive equity instruments as of December 31, 2022 as there were no equity awards of the Company’s ordinary shares prior to the Separation.

On November 15, 2023, the effective date of the Distribution, 16,689,740 of the Company’s ordinary shares were distributed to the Former Parent’s shareholders of record as of November 6, 2023, the record date for the Distribution. This share amount was utilized for the calculation of basic and diluted earnings per share for periods prior to the Separation as there were no shares of the Company outstanding prior to the Separation.

As of December 31, 2023 and 2022, the number of ordinary shares underlying potentially dilutive securities consist of:


	December 31,
	2023		2022
Options to purchase ordinary shares		3,348,715		—
Restricted share units		1,129,512		—
Total		4,478,227		—

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Basis of Presentation and Significant Accounting Policies
Long-term restricted cash	$ 258,000	$ 0
Cash and cash equivalents prior to separation		0
Cash and cash equivalents	270,852,000	0
Other current assets	787,000	1,830,000
Impairment charges	$ 0	0
Share-Based Payment Arrangement, Nonemployee
Basis of Presentation and Significant Accounting Policies
Vesting period	3 years
Tranche One \| Share-Based Payment Arrangement, Employees
Basis of Presentation and Significant Accounting Policies
Vesting percentage	25.00%
Vesting period	4 years
Tranche Two \| Share-Based Payment Arrangement, Employees
Basis of Presentation and Significant Accounting Policies
Vesting percentage	75.00%
Vesting period	3 years
401(K) Plan
Basis of Presentation and Significant Accounting Policies
Retirement savings plan employer matching contribution	100.00%
Retirement savings plan expenses	$ 1,900,000	1,600,000
Retirement savings plan employee pay percentage	5.00%
Rebates
Basis of Presentation and Significant Accounting Policies
Other current assets		$ 1,800,000
Interest receivable
Basis of Presentation and Significant Accounting Policies
Other current assets	$ 800,000
Maximum \| 401(K) Plan
Basis of Presentation and Significant Accounting Policies
Retirement savings plan emplyee contribution percentage	100.00%

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
CURRENT ASSETS:
Cash and cash equivalents	$ 270,852	$ 0
Receivable from former parent	5,548	0
Prepaid expenses	150	2,987
Other current assets	787	1,830
Total current assets	277,337	4,817
Property and equipment, net	11,403	10,617
Right-of-use assets	12,747	18,316
Restricted cash	258	0
TOTAL ASSETS	301,745	33,750
CURRENT LIABILITIES:
Accounts payable	5,973	2,966
Accrued expenses	16,946	32,750
Operating lease liabilities - short-term	6,098	5,844
Total current liabilities	29,017	41,560
Operating lease liabilities - long-term	8,911	13,542
Other long-term liabilities	0	304
Total liabilities	37,928	55,406
Commitments and contingencies (Note 9)
Net parent investment	0	(21,656)
Preferred shares, nominal value $0.01; 50,000,000 shares authorized at December 31, 2023; no shares issued or outstanding at December 31, 2023 or 2022	0	0
Ordinary shares, nominal value $0.01; 450,000,000 ordinary shares authorized at December 31, 2023; 16,689,740 shares issued and outstanding at December 31, 2023 and no shares issued or outstanding at December 31, 2022	167	0
Additional paid-in capital	294,507	0
Accumulated deficit	(30,857)	0
Total equity (deficit)	263,817	(21,656)
TOTAL LIABILITIES AND EQUITY (DEFICIT)	$ 301,745	$ 33,750

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (207,447)	$ (189,807)
Adjustments to reconcile net loss to cash flows from operating activities:
Depreciation	2,567	1,540
Share-based compensation expense	24,109	11,931
Changes in assets and liabilities:
Prepaid expenses	2,837	(787)
Other current assets	1,043	209
Right-of-use assets	7,054	5,909
Accounts payable and accrued expenses	(18,246)	8,389
Operating lease liabilities	(5,862)	(5,920)
Other long-term liabilities	(304)	(52)
Cash flows used in operating activities	(194,249)	(168,588)
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions of property and equipment	(3,452)	(5,511)
Cash flows used in investing activities	(3,452)	(5,511)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net transfers from Former Parent	468,811	174,099
Cash flows provided by financing activities	468,811	174,099
Net increase in cash, cash equivalents and restricted cash	271,110
Cash and cash equivalents and restricted cash, end of period	271,110
Non-cash investing and financing activities:
Purchased capital expenditures included in accounts payable and accrued expenses	276	375
RECONCILIATION OF BALANCE SHEET TO STATEMENT OF CASH FLOWS:
Cash and cash equivalents	270,852	$ 0
Restricted cash	258
Total cash, cash equivalents and restricted cash as shown in the statement of cash flows	$ 271,110

Income Taxes - Additional Information (Details)	12 Months Ended
Income Taxes - Additional Information (Details)	Dec. 31, 2023 USD ($) TaxReturn	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Income Taxes [Line Items]
Income tax expense (benefit)	$ 12,160,000	$ 4,884,000
Unremitted earnings	0
Deferred tax asset valuation allowance domestic	5,900,000
Unrecognized tax benefits	$ 0	$ 2,132,000	$ 1,784,000
Income tax examination year	2023
Number of tax returns filed \| TaxReturn	0
Irish NOLs
Income Taxes [Line Items]
NOL Carryforwards	$ 200,000
Federal
Income Taxes [Line Items]
NOL Carryforwards	2,900,000
Federal \| R&D Credits
Income Taxes [Line Items]
Tax credit	$ 500,000
Tax credit carryforward expiration period	2038

Related Parties

12 Months Ended

Dec. 31, 2023

Related Parties

11. Related Parties

Corporate expenses prior to the Separation represent shared costs of the Former Parent that have been allocated to the Company based on a systematic and rational methodology and are reflected as expenses in these consolidated financial statements. These amounts include, but are not limited to, items such as general management and executive oversight, costs to support the Company’s information technology infrastructure, facilities, compliance, human resources, legal and finance functions, risk management, and share-based compensation administration, all of which support the operations of the Former Parent as a whole. Corporate expense allocations in the periods prior to the Separation were generally allocated to the Company based on proportional cost allocation methods using headcount, square footage, or proportional hours worked supporting the Company and other organizational activities, as applicable, which are considered to be reasonable reflections of the utilization of services provided or benefit received by the Company during the periods presented. Total corporate expense allocations from the Former Parent for the periods prior to the Separation in general and administrative expenses were $17.9 million and $17.7 million during the years ended December 31, 2023 and 2022, respectively. Total corporate expense allocations from the Former Parent for the periods prior to the Separation in R&D expenses were $146.6 million and $167.2 million during the years ended December 31, 2023 and 2022, respectively. The Former Parent assumed all of the outstanding accrued liabilities and accounts payable related to the oncology business as of the date of the Separation.

Management considers the allocation methodologies used to be reasonable and appropriate reflections of the related expenses attributable to the Company for purposes of the consolidated financial statements; however, the expenses reflected in

these financial statements may not be indicative of the actual expenses that would have been incurred during the periods presented if the Company had operated as a standalone entity. In addition, the expenses reflected in the consolidated financial statements may not be indicative of expenses that will be incurred in the future by the Company.

See Note 1, Organization and Description of Business, for details of the Company’s cash and financing arrangements. As of the date these consolidated financial statements were available for issuance, there were no existing debt or other financing agreements in place with the Former Parent. As of December 31, 2023, the Company had a receivable from the Former Parent of $5.5 million pursuant to the transition services agreements. See Note 2, Basis of Presentation and Summary of Significant Accounting Policies, for additional information on the preparation and basis of presentation of these consolidated financial statements, including the treatment of certain R&D costs not directly attributable to individual programs, cash and cash equivalents, share-based compensation, and 401(k) Plan expenses.

As of the date of the Separation, the Former Parent is no longer a related party to the Company.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
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-Paragraph 1
-Subparagraph (SX 210.6-07(2)(e))
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-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//850/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147483326/850-10-50-6

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

+ Details

Organization and Description of Business

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization and Description of Business

1. Organization and Description of Business

Mural Oncology plc and its consolidated subsidiaries (“Mural” or “the Company”), an Irish public limited company incorporated in 2023, is a clinical-stage oncology business focused on discovering and developing immunotherapies that may meaningfully improve the lives of patients with cancer. By leveraging its core competencies in immune cell modulation and protein engineering, the Company has developed a portfolio of investigational cytokine therapies designed to address areas of unmet need for patients with a variety of cancers.

The accompanying financial statements include the combined, historical financial position, results of operations, net parent investment and cash flows of Alkermes plc, an Irish public limited company, and its consolidated subsidiaries’ (the “Former Parent” or “Alkermes”) oncology business (the “oncology business”) as it was historically managed as part of the Former Parent’s prior to the completion of the separation of the oncology business from the Former Parent’s neuroscience business on November 15, 2023 (the “Separation”), and the creation of the Company, as a result of the Distribution (as defined below) as an independent, publicly traded company, which holds the assets, liabilities and operations associated with the oncology business.

The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry. There can be no assurance that the Company’s research and development (“R&D”) will be successfully completed, that any products developed will obtain necessary government regulatory approval or that any products, if approved, will be commercially viable. The Company operates in an environment of rapid technological innovation and substantial competition from pharmaceutical and biotechnological companies. In addition, the Company is dependent upon the services of its employees, consultants and service providers. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant product revenue from product sales.

The Separation

On November 2, 2022, the Former Parent announced its intent, as approved by its board of directors, to explore the Separation.

In connection with the Separation, on November 13, 2023, the Company entered into certain agreements with the Former Parent to provide a framework for the Company’s relationship with the Former Parent following the Separation. These agreements include:

•

a separation agreement;

•

a tax matters agreement;

•

an employee matters agreement;

•

a lease assumption agreement; and

•

transition services agreements.

The separation agreement sets forth the Company’s agreements with the Former Parent regarding the principal actions to be taken by the Company and the Former Parent in connection with the Separation, including those related to the distribution of the Company’s ordinary shares to the Former Parent’s shareholders (the “Distribution”). The separation agreement identifies the assets transferred to, liabilities assumed by and contracts assigned to the Company, including the Winter Street Lease, as part of the Separation, and provides for when and how such transfers, assumptions and assignments occurred. Under the terms of the separation agreement, the Former Parent granted the Company a perpetual, worldwide, non-exclusive, royalty-free, fully paid-up license (or, as the case may be, sublicense) to any intellectual property controlled by the Former Parent as of the date of the Distribution, allowing the Company to use such intellectual property for the oncology business, and the Company granted the Former Parent a perpetual, worldwide, non-exclusive, royalty-free, fully paid-up license (or, as the case may be, sublicense) to intellectual property transferred to the Company as part of the Separation for the Former Parent’s use outside of the oncology business. Each of the Company and the Former Parent agreed to releases with respect to pre-Distribution claims, and cross-indemnities with respect to post-Distribution claims, that are principally designed to place financial responsibility for the obligations and liabilities allocated to the Company under the separation agreement with the Company, and financial responsibility for the obligations and liabilities allocated to the Former Parent under the separation agreement with the Former Parent. The Company and the Former Parent are also each subject to mutual six-month employee non-solicitation and non-hire restrictions, subject to certain customary exceptions, and certain confidentiality restrictions and information sharing obligations.

The tax matters agreement governs the Company’s and the Former Parent’s respective rights, responsibilities, and obligations with respect to taxes (including taxes arising in the ordinary course of business and incurred as a result of any failure of the Distribution, together with certain related transactions, to qualify as tax-free for U.S. federal income tax purposes), tax attributes, the preparation and filing of tax returns, the control of audits and other tax proceedings, and assistance and cooperation in respect to tax matters.

The employment matters agreement, as amended in December 2023, governs the Company’s and the Former Parent’s rights, responsibilities, and obligations after the Separation with respect to employment, benefits and compensation matters relating to employees and former employees (and their respective dependents and beneficiaries) who are or were associated with the Former Parent, including those who became employees of the Company in connection with the Separation. The employee matters agreement also specifies the allocation of assets and liabilities generally relating to employees, employment or service-related matters and employee benefit plans; other human resources, employment and employee benefits matters; and the treatment of equity-based awards granted by the Former Parent prior to the Separation to employees who became employees of the Company in connection with the Separation.

Under the terms of the lease assumption agreement, the Company assumed all of the Former Parent’s obligations under the Winter Street Lease.

The Company and the Former Parent entered into two transition services agreements, pursuant to one of which the Former Parent and its subsidiaries agreed to provide, on an interim, transitional basis, various services to the Company, and the second of which the Company and its subsidiaries agreed to provide certain services to the Former Parent, in each case for a term of two years following the Separation, unless earlier terminated in accordance with the terms of the applicable agreement.

On November 14, 2023, in connection with the Separation, the Company received a cash contribution of $275.0 million from the Former Parent.

The Former Parent effected the Separation through the distribution of the ordinary shares of the Company to the Former Parent’s shareholders (the “Distribution”) on November 15, 2023. As part of the Separation, the Former Parent transferred the assets, liabilities and operations of the historical oncology business to the Company, pursuant to the terms of a separation agreement, entered into between the Company and the Former Parent. Liabilities incurred prior to the Separation remained obligations of the Former Parent unless otherwise specified in the agreements entered into between the Company and the Former Parent. On the effective date of the Distribution, each Alkermes shareholder received one ordinary share of the Company for every ten ordinary shares of Alkermes held as of the close of business on November 6, 2023, the record date for the Distribution. Registered shareholders received cash in lieu of any fractional ordinary shares of the Company that they would have received as a result of the application of the distribution ratio. As a result of the Separation and the Distribution, the Company operates as an independent, publicly traded company and commenced trading under the symbol “MURA” on the Nasdaq Global Market on November 16, 2023.

Liquidity

Under Accounting Standards Update ("ASU") No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40), the Company has the responsibility to evaluate whether conditions and/or events raise substantial doubt about its ability to meet its future financial obligations as they become due within one year after the date that the financial statements are issued. The Company has generated operating losses for all the historical periods presented and expects to continue to generate operating losses for the foreseeable future. The Company expects to fund its operations and capital needs through the funding received from the Former Parent through the date of the Separation, including the cash contribution of $275.0 million received from the Former Parent at the time of the Separation. The Company’s continued operations were dependent on the funding received from the Former Parent through the Separation and, going forward, will be dependent on its ability to generate cash from operating activities and to raise additional capital to finance its future operations subsequent to the Separation. The Company will need additional financing to support its continuing operations and further develop or commercialize any product candidates. If the Company is unable to obtain additional funding on a timely basis, it may be forced to significantly curtail, delay, or discontinue one or more of the planned research or development programs or be unable to expand or continue operations. There is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all. For the four-year period beginning two years before and ending two years after the Distribution, the Company is prohibited under the tax matters agreement with the Former Parent from taking or failing to take actions that would prevent the Separation and the Distribution, in relevant part and together with certain related transactions, from qualifying as transactions that are tax-free for U.S. federal income tax purposes under Sections 355 and 368(a)(1)(D) of the Internal Revenue Code of 1986, which may limit for a period of time the Company’s ability to pursue certain strategic transactions, equity issuances or repurchases or other transactions.

The Company expects that, based on its current operating plans, the Company’s existing cash and cash equivalents will be sufficient to fund its current planned operations for at least the next twelve months from the issuance of these consolidated financial statements.

Income Taxes - Summary of Activity in Valuation Allowance Associated with Deferred Taxes (Parenthetical) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Valuation Allowance [Line Items]
Change in deferred tax asset valuation allowance benefit recognized	$ (50,151,000)	$ (43,344,000)
Irish NOLs
Valuation Allowance [Line Items]
Change in deferred tax asset valuation allowance benefit recognized		$ 0

Fair Value - Schedule of Financial Assets Measured and Recognized at Fair Value on a Recurring Basis (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Assets:
Total		$ 0
Recurring
Assets:
Total	$ 268,720,000
Recurring \| Level 1
Assets:
Total	268,720,000
Recurring \| Money Market Mutual Funds
Assets:
Cash equivalents	268,720,000
Recurring \| Money Market Mutual Funds \| Level 1
Assets:
Cash equivalents	$ 268,720,000

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 2,567	$ 1,540

Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Assumption Estimate Fair Value of Stock Options Granted

The following average assumptions were used to estimate the fair value of stock options granted by Mural following the Separation using the Black-Scholes option pricing model:


	Year Ended December 31, 2023
Risk-free interest rate		4.1	%
Dividend rate		0	%
Expected volatility		87.1	%
Expected life (years)		6.03

Summary of Stock Option Activity

A summary of stock option activity under the 2023 Plan for the year ended December 31, 2023 is as follows:


	Number of Options		Weighted-Average Exercise Price
Options outstanding at December 31, 2022		—	$	—
Aggregate impact of conversion related to the Separation		2,756,173	$	4.73
Granted		592,542	$	3.61
Options outstanding at December 31, 2023		3,348,715	$	4.53
Options exercisable at December 31, 2023		741,936	$	4.97

The weighted average grant date fair value of stock options granted during the year ended December 31, 2023 was $2.69. At December 31, 2023, there were 3.1 million stock options vested or expected to vest, with a weighted average exercise price of $4.53 per share, a weighted average contractual remaining life of 6.1 years and an aggregate intrinsic value of $4.4 million. At December 31, 2023, the aggregate intrinsic value of stock options exercisable was $0.7 million with a weighted average remaining contractual term of 4.2 years. The number of stock options expected to vest was determined by applying the pre-vesting forfeiture rate to the total number of outstanding options. The intrinsic value of a stock option is the amount by which the market value of the underlying shares exceeds the exercise price of the stock option.

At December 31, 2023, there was $4.3 million of unrecognized share-based compensation expense related to unvested stock options, which is expected to be recognized over a weighted average period of 2.0 years.

Summary of Restricted Share Activity

A summary of RSU activity under the 2023 Plan for the year ended December 31, 2023 is as follows:


	Number of Shares		Weighted-Average Grant Date Fair Value Per Share
Unvested outstanding at December 31, 2022		—	$	—
Aggregate impact of conversion related to the Separation		863,787	$	4.71
Granted		265,725	$	3.61
Unvested outstanding at December 31, 2023		1,129,512	$	4.45

Schedule of Share-Based Compensation Expense

The following table represents share-based compensation expense included in the Company’s consolidated statements of operations and comprehensive loss:


	Year Ended December 31,
(in thousands)	2023		2022
Research and development	$	11,550	$	9,515
General and administrative		12,559		2,416
Total share-based compensation expense	$	24,109	$	11,931

Share-Based Compensation - Summary of Stock Option Activity (Details) - 2023 Plan	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Aggregate impact of conversion related to the Separation, Number of Options \| shares	2,756,173
Granted, Number of Options \| shares	592,542
Options outstanding at December 31, 2023, Number of Options \| shares	3,348,715
Options exercisable at December 31, 2023, Number of Options \| shares	741,936
Aggregate impact of conversion related to the Separation, Weighted-Average Exercise Price \| $ / shares	$ 4.73
Granted, Weighted-Average Exercise Price \| $ / shares	3.61
Options outstanding at December 31, 2023, Weighted-Average Exercise Price \| $ / shares	4.53
Options exercisable at December 31, 2023, Weighted-Average Exercise Price \| $ / shares	$ 4.97

Property and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment, Net

Property and equipment, net consisted of the following:


(in thousands)	December 31, 2023			December 31, 2022
Furniture, fixtures and equipment	$	21,738		$	17,470
Leasehold improvements		23,333			22,510
Construction in progress		15			1,989
Subtotal		45,086			41,969
Less: accumulated depreciation		(33,683	)		(31,352	)
Total property and equipment, net	$	11,403		$	10,617

Basis of Presentation and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Basis of Presentation and Summary of Significant Accounting Policies

2. Basis of Presentation and Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements include the accounts of Mural Oncology plc and its wholly-owned subsidiaries. For the periods prior to the Separation, the accompanying combined financial statements of the Company have been prepared on a standalone basis and are derived from the Former Parent’s consolidated financial statements and accounting records. All intercompany transactions and accounts within the Company have been eliminated.

The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and, for the periods prior to the Separation, reflect the historical results of operations, financial position and cash flows of Mural, as included in the consolidated financial statements of the Former Parent and using the Former Parent’s historical accounting policies. These consolidated financial statements do not purport to reflect what the Company’s results of operations, financial position or cash flows would have been had the Company operated as a standalone public company prior to the separation, nor are they necessarily indicative of the Company’s future results of operations, financial position, or cash flows.

As the Company’s operations were not historically held by a single legal entity or separate legal entities, net parent investment is shown in lieu of stockholders’ equity in the historical combined financial statements for the periods prior to the Separation. Net parent investment represents the cumulative investment by the Former Parent in the Company through the dates presented, inclusive of operating results. All transactions between the Company and the Former Parent are considered to be effectively settled in the consolidated financial statements at the time the transaction is recorded. The effects of the settlement of these transactions between the Company and the Former Parent are reflected in the consolidated statements of cash flows as “Net transfers from Former Parent” within financing activities and in the consolidated balance sheets and consolidated statements of equity (deficit) as “Net parent investment”.

Historically, the Company was dependent upon the Former Parent for all of its working capital and financing requirements, as the Former Parent used a centralized approach to cash management and financing its operations. There were no cash amounts specifically attributable to the Company for the historical periods presented prior to the Separation; therefore, cash and cash equivalents have not been included in the consolidated financial statements for the year ended December 31, 2022. Financing transactions prior to the Separation related to the Former Parent are accounted for as a component of net parent investment in the consolidated balance sheet as of December 31, 2022 and as a financing activity on the accompanying consolidated statements of cash flows through the date of the Separation. In connection with the Separation, certain assets and liabilities that were included on the consolidated balance sheet prior to the Separation were retained by the Former Parent and were therefore adjusted through net parent investment in the Company’s consolidated financial statements.

The consolidated financial statements of the Company include, for the periods prior to the Separation, the assets, liabilities, and expenses of the Former Parent that management has determined are specifically identifiable to the Company, such as those related to direct internal and external R&D activities as well as leases and fixed assets specifically identifiable to the oncology business. Based on the nature of the Company as a pre-revenue, development-stage biotechnology company, the consolidated financial statements of the Company do not include any revenue or commercial expenses of the Former Parent. The consolidated financial statements of the Company also include, for the periods prior to the Separation, an allocation of costs that were not directly attributable to the operations of the Company, including the costs of general and administrative support functions that were provided by the Former Parent, such as senior management, information technology, legal, accounting and finance, human resources, facility, and other corporate services. In addition, the Company’s consolidated financial statements include, for the periods prior to the Separation, an allocation of certain R&D costs not directly attributable to individual programs. These costs have been allocated to the Company for the purposes of preparing the consolidated financial statements based on proportional cost allocation methods using headcount, square footage or proportional hours worked supporting the Company and other organizational activities, as applicable, which are considered to be reasonable reflections of the utilization of services provided or benefit received by the Company during the periods presented. Management considers that such allocations have been made on a reasonable basis; however, these allocations may not necessarily be indicative of the costs that would have been incurred if the Company had operated on a standalone basis for the periods presented and, therefore, may not reflect the Company’s results of operations, financial position, and cash flows had the Company operated as a standalone entity during the periods presented. See Note 11, Related Parties, for additional information regarding related-party transactions with the Former Parent.

The Company expects to incur additional operating expenses to operate as an independent publicly traded company, including various corporate functions, incremental information technology-related costs and incremental costs to operate standalone accounting, legal and other administrative functions. These functions were provided to the Company prior to the Separation by the Former Parent and will continue under a transition services agreement or will be performed using the Company’s own resources.

Use of Estimates

The preparation of the Company’s consolidated financial statements in accordance with GAAP requires the Company to make estimates, judgments and assumptions that may affect the reported amounts of assets, liabilities and expenses and the related disclosure of contingent assets and liabilities. On an ongoing basis, the Company evaluates its estimates and judgments and methodologies, including but not limited to, those related to allocations of expenses, assets and liabilities from the Former Parent’s historical financials to the Company, the impairment of long-lived assets, share-based compensation, leases, and income taxes including the valuation allowance for deferred tax assets. The Company bases its estimates on historical experience of the Former Parent and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ from these estimates under different assumptions or conditions.

Cash and Cash Equivalents and Restricted Cash

The Company considers cash equivalents only those investments that are highly liquid, readily convertible into cash and so near their maturity, generally three months from the date of purchase, that they present insignificant risk of change in value because of interest rate changes.

At December 31, 2023, the Company also had a long-term restricted cash balance of $0.3 million for cash restricted for use pertaining to corporate credit cards.

There were no cash or cash equivalents specifically attributable to the Company prior to the Separation; therefore, there are no cash or cash equivalents reflected in the combined financial statements as of December 31, 2022.

Fair Value Measurements

The Company’s financial assets and liabilities are recorded at fair value and are classified as Level 1, 2 or 3 within the fair value hierarchy, as described in the accounting standards for fair value measurement. Financial assets and liabilities are classified within the fair value hierarchy as follows:

•

Level 1—Quoted prices in active markets for identical assets or liabilities.

•

Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

•

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.

The carrying amounts reflected in the consolidated balance sheets for prepaid expenses, receivable from Former Parent, other current assets, accounts payable, and accrued expenses approximate fair value due to their short-term nature. Other current assets consists of interest receivable of $0.8 million as of December 31, 2023 and of rebates from a clinical research organization of $1.8 million as of December 31, 2022. The Company has elected to exclude accrued interest receivable from the amortized cost of its financial assets and has included those balances within Other current assets on the consolidated balance sheet.

Receivable from Former Parent

The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for estimated amounts of receivables that will not be collected, if any. The Company believes that the credit risks associated with its receivables are not significant and, therefore, the Company did not have an allowance for doubtful receivables as of December 31, 2023.

Property and Equipment

Property and equipment are recorded at cost, subject to assessment for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Expenditures for repairs and maintenance are charged to expense as incurred and major renewals and improvements are capitalized. Depreciation is calculated using the straight-line method over the following estimated useful lives of the assets:


Asset group		Term
Furniture, fixtures and equipment		3 - 10 years
Leasehold improvements		Shorter of useful life or lease term

Leases

The Company accounts for leases under Accounting Standards Codification (“ASC”) 842, Leases. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the relevant facts and circumstances present in the arrangement. Leases with a term greater than one year are recognized on the balance sheet as right-of-use assets and short-term and long-term lease liabilities, as applicable. The Company does not have material financing leases.

Leases contain both lease and non-lease components. Non-lease components may include maintenance, utilities, and other operating costs. The Company combines the lease and non-lease components in its lease arrangements as a single lease component. Variable costs, such as utilities or maintenance costs, are not included in the measurement of right-of-use assets and lease liabilities, but rather are expensed when the event determining the amount of variable consideration to be paid occurs.

Operating lease liabilities and their corresponding right-of-use assets are initially recorded at the lease commencement date based on the present value of lease payments over the expected remaining lease term. Certain adjustments to right-of-use assets may be required for items such as prepaid or accrued lease payments as well as incentives received. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes an incremental borrowing rate to discount lease payments, which reflects the fixed rate at which the Company could borrow on a collateralized basis the amount of the lease payments in the same currency, for a similar term, in a similar economic environment. To estimate the incremental borrowing rate, a credit rating applicable to us is estimated using a synthetic credit rating analysis since the Company does not currently have a rating agency-based credit rating. Operating lease payments are expensed using the straight line method as an operating expense over the lease term.

The Company has elected not to recognize leases with an original term of one year or less on the balance sheet. The Company typically only includes an initial lease term in its assessment of a lease arrangement. Options to renew a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will renew.

Assumptions that the Company made at the commencement date are re-evaluated upon occurrence of certain events, including a lease modification. A lease modification results in a separate contract when the modification grants the lessee an additional right of use not included in the original lease and when lease payments increase commensurate with the standalone price for the additional right of use. When a lease modification results in a separate contract, it is accounted for in the same manner as a new lease.

Impairment of Long-Lived Assets

The Company reviews long-lived assets to be held and used for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Conditions that would necessitate an impairment assessment include a significant decline in the observable market value of an asset; a significant change in the extent or manner in which an asset is used; a significant adverse change in legal factors or in the business climate that could affect the value of a long-lived asset; an accumulation of costs significantly in excess of the amount originally expected for the acquisition or construction of a long-lived asset; a current-period operating or cash flow loss combined with a history of operating or cash-flow losses or a projection or forecast that demonstrates continuing losses associated with the use of a long-lived asset; or a current expectation that, more likely than not, a long-lived asset will be sold or otherwise disposed of significantly before the end of its previously

estimated useful life. Determination of recoverability is based on an estimate of undiscounted future cash flows resulting from the use of the asset and its eventual disposition. In the event that such cash flows are not expected to be sufficient to recover the carrying amount of the assets, the assets are written-down to their estimated fair values. Long-lived assets to be disposed of are carried at fair value less costs to sell them. The Company has not recorded any impairment charges for the years ended December 31, 2023 and 2022.

Research and Development Expenses

For each of its R&D programs, the Company incurs both external and internal expenses. External R&D expenses include fees related to clinical and non-clinical activities performed by contract research organizations, consulting fees and costs related to laboratory services, purchases of drug product materials, and third-party manufacturing development costs. Internal R&D expenses include employee-related expenses, including share-based compensation, occupancy costs, depreciation, and general R&D overhead. Prior to the Separation, these expenses included allocations from the Former Parent.

Clinical Trial and Preclinical Study Expenses

The Company makes estimates of prepaid and/or accrued expenses as of each balance sheet date in its consolidated financial statements based on certain facts and circumstances at that time. The Company’s accrued expenses for preclinical studies and clinical trials are based on estimates of costs incurred for services provided by contract research organizations (“CROs”), manufacturing organizations, and for other trial- and study-related activities. Payments under the Company’s agreements with external service providers depend on a number of factors such as site initiation, patient screening, enrollment, delivery of reports, and other events. In accruing for these activities, the Company obtains information from various sources and estimates the level of effort or expense allocated to each period. Adjustments to R&D expenses may be necessary in future periods as the Company’s estimates change. As these activities are generally material to the Company’s financial statements, subsequent changes in estimates may result in a material change in accruals. No material changes in estimates were recognized in either of the years ended December 31, 2023 and 2022.

General and Administrative Expenses

General and administrative expenses are primarily comprised of employee-related expenses associated with finance, human resources, legal, information technology and other administrative personnel, and occupancy costs, depreciation and third-party expenses related to financial, legal and other general and administrative functions. Prior to the Separation, these expenses included allocations from the Former Parent.

Share-Based Compensation

Certain employees of the Company participate in the Company’s share-based compensation plans and, prior to the Separation, participated in the Former Parent’s share-based compensation plans. Share-based compensation expense of the Company related to the Former Parent’s plans was recognized through allocations based on methodologies that management believes are consistent and reasonable, utilizing headcount or proportional hours worked supporting the Company and other organizational activities, as appropriate.

Share-based compensation expense is recognized over the requisite service period of the awards, which is generally the vesting period. Subsequent to the Separation, option awards granted to employees generally vest over a four year period, with 25% vesting on the first anniversary of the date of grant and the remaining 75% vesting quarterly over the remaining three years, provided the employee remains continuously employed by the Company during the applicable vesting period; option awards granted to non-employee directors generally vest over a three-year period, provided that the director continues to serve on the Company’s board of directors during the applicable vesting period; and restricted stock unit (“RSU”) awards generally vest in four equal annual installments, commencing on the first anniversary of the date of grant, provided the employee remains continuously employed by the Company during the applicable vesting period. See Note 6, Share-Based Compensation, for more information.

Due to its limited operating history and a limited trading history of its ordinary shares in relation to the life of its stock option grants, the Company estimates the volatility of its ordinary shares based on the volatility of comparable public companies. The expected life of a stock option is based on the average of the contractual term (generally ten years) and the vesting period.

The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant. The assumed dividend yield is based on the Company’s expectation of not paying dividends in the foreseeable future.

Income Taxes

Prior to the Separation, the Company was included in the Former Parent’s income tax returns, and all income taxes were paid by the Former Parent. Income tax expense and other income tax related information contained in these consolidated financial statements prior to the Separation are presented on a separate return approach as if the Company filed its own tax returns for those periods. Under this approach, the provision for income taxes represents income tax paid or payable (or received or receivable) for the current year plus the change in deferred taxes during the year calculated as if the Company were a standalone taxpayer filing hypothetical income tax returns, where applicable. Current income tax liabilities were assumed to be immediately settled with the Former Parent and were relieved through “Net parent investment” account and reflected as “Net transfers from Former Parent” within financing activities in the historical combined statements of cash flows for periods prior to the Separation. Certain prior period amounts in the consolidated financial statements have been reclassified to conform to the current period presentation.

The Company recognizes income taxes under the asset and liability method. Deferred income taxes are recognized for differences between the financial reporting and tax bases of assets and liabilities at enacted statutory tax rates in effect for the years in which the differences are expected to reverse. The effect on deferred taxes of a change in tax rates is recognized in income in the period that includes the enactment date. In evaluating the Company’s ability to recover its deferred tax assets, the Company considers all available positive and negative evidence including its past operating results, the existence of cumulative losses in the most recent fiscal years, changes in the business in which the Company operates and its forecast of future taxable income. In determining future taxable income, the Company is responsible for assumptions utilized, including the amount of U.S. and non-U.S pre-tax operating income, the reversal of temporary differences and the implementation of feasible and prudent tax planning strategies. These assumptions require significant judgment about the forecasts of future taxable income and are consistent with the plans and estimates that the Company is using to manage the underlying business.

The Company accounts for uncertain tax positions using a more-likely-than-not threshold for recognizing and resolving uncertain tax positions. The evaluation of uncertain tax positions is based on factors including, but not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, new audit activity and changes in facts or circumstances related to a tax position. The Company also accrues for potential interest and penalties related to unrecognized tax benefits in income tax expense.

Comprehensive Loss and Loss per Share

Comprehensive loss is comprised of net loss and other comprehensive loss. The Company has no components of other comprehensive loss. Therefore, net loss equals comprehensive loss for all periods presented.

Basic net loss per share is computed by dividing the net loss in each period by the weighted average number of ordinary shares outstanding during such period. Diluted net loss per share is computed similarly to basic net loss per share except that the denominator is increased to include the number of additional ordinary shares that would have been outstanding if the potential ordinary shares had been issued and if the additional ordinary shares were dilutive. For the periods presented, ordinary share equivalents, consisting of share-based awards, were not included in the calculation of the diluted net loss per share because to do so would be anti-dilutive. The number of shares distributed to the Former Parent’s shareholders of record on the effective date of the Distribution was used for the calculation of basic and diluted earnings per share for periods prior to the Separation as the Company had no shares outstanding prior to the Separation.

Segment Information

The Company operates as one business segment, which is the business of developing medicines designed to address unmet medical needs of patients in the area of oncology. The Company’s chief operating decision maker reviews the Company’s operating results on an aggregate basis and manages operations as a single operating unit. Prior to the Separation, the Company’s chief operating decision maker was the Chairman and Chief Executive Officer of the Former Parent. After the Separation, the Company’s chief operating decision maker is the Company’s Chief Executive Officer. All of the Company’s long-lived assets are held in Massachusetts.

401(k) Plan

The Company maintains a 401(k) retirement savings plan (the “401(k) Plan”), which covers substantially all of its U.S.-based employees. Eligible employees may contribute up to 100% of their eligible compensation, subject to certain IRS

limitations. The Company matches 100% of employee contributions up to the first 5% of employee pay, up to IRS limits. Employee and employer contributions are fully vested when made. Prior to the Separation, the Former Parent included in its 401(k) retirement savings plan substantially all of the employees of the Former Parent who would become employees of the Company. During the years ended December 31, 2023 and 2022, expenses related to the 401(k) Plan that were incurred by the Company after the Separation or that were allocated to Mural prior to the Separation totaled $1.9 million and $1.6 million, respectively.

Recently Issued Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (the “FASB”) or other standard-setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption.

In November 2023, the FASB issued Accounting Standards Update (“ASU”) No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 280”). ASU 280 requires public entities to disclose significant segment expenses that are regularly provided to the chief operating decision maker and to disclose how reported measures of segment profit or loss are used in assessing segment performance and allocating resources. The amendments in ASU-280 are effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is evaluating the impact of the adoption of ASU-280 on its consolidated financial statements and related disclosures and does not expect the adoption of ASU-280 to have a material impact on the Company’s consolidated financial statements.

In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU-740”). ASU-740 requires public entities to provide enhanced disclosure of specific categories of reconciling items included in the rate reconciliation; disclosure of the nature, effect and underlying causes of each reconciling item in the rate reconciliation and the judgment used in the categorization of such items; and enhanced disclosures for income taxes paid. The amendments in this ASU are effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is evaluating the impact of the adoption of ASU-740 on its consolidated financial statements and disclosures.

Leases - Schedule of Future Lease Payments under Non-cancelable Leases (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Leases [Abstract]
2024	$ 6,496
2025	6,642
2026	2,484
Total operating lease payments	15,622
Less: imputed interest	(613)
Total operating lease liabilities	$ 15,009

Fair Value - Additional Information (Details)	Dec. 31, 2022 USD ($)
Fair Value Disclosures [Abstract]
Financial assets at fair value	$ 0

Income Taxes - Summary of Income Loss Before Provision For Income Taxes by Geographical Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Ireland	$ (187,172)	$ (178,693)
U.S.	(8,115)	(6,230)
Loss before the provision for income taxes	$ (195,287)	$ (184,923)

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(11))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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-Name Accounting Standards Codification
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-Paragraph 30
-Subparagraph (b)
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-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 32
-Subparagraph (f)
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Reference 5: http://www.xbrl.org/2003/role/exampleRef
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-Name Accounting Standards Codification
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-Paragraph 31
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (c)
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
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-Topic 940
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-URI https://asc.fasb.org//1943274/2147481913/940-20-25-1

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(10))
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-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(15))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 2,132,000	$ 1,784,000
Additions based on tax positions related to the current period		348,000
Subtractions based on tax positions related to the current period	(2,132,000)
Ending balance	$ 0	$ 2,132,000

Basis of Presentation and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Estimated Useful Lives of Assets

Depreciation is calculated using the straight-line method over the following estimated useful lives of the assets:


Asset group		Term
Furniture, fixtures and equipment		3 - 10 years
Leasehold improvements		Shorter of useful life or lease term

Summary of Assumption Estimate Fair Value of Stock Options Granted

The following average assumptions were used to estimate the fair value of stock options granted by Mural following the Separation using the Black-Scholes option pricing model:


	Year Ended December 31, 2023
Risk-free interest rate		4.1	%
Dividend rate		0	%
Expected volatility		87.1	%
Expected life (years)		6.03

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (207,447)	$ (189,807)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 6
-Publisher FASB
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+ Details

Share-Based Compensation - Schedule of Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	$ 24,109	$ 11,931
Research and Development
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	11,550	9,515
General and Administrative
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	$ 12,559	$ 2,416

Net Loss Per Share - Schedule of Number of Ordinary Shares Underlying Potentially Dilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	4,478,227	0
Employee Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	3,348,715
Restricted Share Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total	1,129,512

Commitments and Contingencies - Additional Information (Details) $ in Millions	Dec. 31, 2023 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Open purchase commitments for noncancellable contract manufacturing costs	$ 12.8

Property and Equipment, Net

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Property and Equipment, Net

3. Property and Equipment, Net

Property and equipment, net consisted of the following:


(in thousands)	December 31, 2023			December 31, 2022
Furniture, fixtures and equipment	$	21,738		$	17,470
Leasehold improvements		23,333			22,510
Construction in progress		15			1,989
Subtotal		45,086			41,969
Less: accumulated depreciation		(33,683	)		(31,352	)
Total property and equipment, net	$	11,403		$	10,617

Depreciation expense was $2.6 million and $1.5 million for the years ended December 31, 2023 and 2022, respectively.

Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Assumption Estimate Fair Value of Stock Options Granted (Details)	12 Months Ended
	Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Risk-free interest rate	4.10%
Dividend rate	0.00%
Expected volatility	87.10%
Expected life (years)	6 years 10 days

Organization and Description of Business - Additional Information (Details) - Alkermes - USD ($) $ in Millions	Nov. 15, 2023	Nov. 14, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Effective time of distribution		Nov. 15, 2023
Cash distribution received from parent		$ 275.0
Distribution term of shares	one ordinary share of the Company for every ten ordinary shares

Income Taxes - Summary Of Provision For Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Current income tax provision:
U.S. federal	$ 12,138	$ 4,858
U.S. state	22	26
Ireland	0	0
Deferred income tax provision:
U.S. federal	0	0
U.S. state	0	0
Ireland	0	0
Total tax provision	$ 12,160	$ 4,884

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Basis of Presentation and Summary of Significant Accounting Policies - Estimated Useful Lives of Assets (Details)	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember
Minimum \| Furniture, Fixtures and Equipment
Property, Plant and Equipment [Line Items]
Useful lives of assets	3 years
Maximum \| Furniture, Fixtures and Equipment
Property, Plant and Equipment [Line Items]
Useful lives of assets	10 years

Commitments and Contingencies

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

9. Commitments and Contingencies

The Company, from time to time, may be involved with lawsuits arising in the ordinary course of business. The Company is not involved in any pending legal proceedings that it believes could have a material adverse effect on its financial condition, results of operations or cash flows.

In the normal course of business, the Company contracts with third parties for preclinical, clinical and other research and development services. These contracts generally do not contain minimum purchase commitments and are cancellable upon notice by the Company. The Company has, however, entered into agreements with contract manufacturing organizations that include noncancellable costs or that may be subject to cancellation fees. As of December 31, 2023, open purchase commitments for such noncancellable contract manufacturing costs totaled approximately $12.8 million.

See Note 5, Leases, for information related to the Company’s lease obligations.

See Note 1, Organization and Description of Business, for information related to the tax matters agreement, which governs the Company’s and the Former Parent’s respective rights, responsibilities, and obligations with respect to taxes and which contains certain indemnifications.

Restructuring - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Restructuring Charges [Abstract]
Restructuring charge	$ 1.6

Consolidated Statements of Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Net Parent Investment	Additional Paid-in Capital	Accumulated Deficit
Beginning balance at Dec. 31, 2021	$ (17,879)		$ (17,879)
Share-based compensation expense	11,931		11,931
Net transfers from Former Parent	174,099		174,099
Net Income (Loss)	(189,807)		(189,807)
Ending balance at Dec. 31, 2022	(21,656)		(21,656)
Cash contribution from Former Parent in connection with Separation	275,000		275,000
Share-based compensation expense allocated from Former Parent	10,813		10,813
Issuance of ordinary shares upon separation from Former Parent		$ 167	(281,378)	$ 281,211
Issuance of ordinary shares upon separation from Former Parent, in shares		16,689,740
Share-based compensation expense	13,296			13,296
Net transfers from Former Parent	193,811		193,811
Net Income (Loss)	(207,447)		$ (176,590)		$ (30,857)
Ending balance at Dec. 31, 2023	$ 263,817	$ 167		$ 294,507	$ (30,857)
Ending balance, in shares at Dec. 31, 2023		16,689,740

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.

+ References + Details

- Definition

Amount of equity (deficit) attributable to parent. Excludes temporary equity and equity attributable to noncontrolling interest.

+ References

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+ Details

Related Parties - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
General and administrative expense	$ 30,706	$ 17,732
Research and development expense	165,532	167,191
Receivable from former parent	5,548	0
Corporate Expense Allocations \| Alkermes
Related Party Transaction [Line Items]
General and administrative expense	17,900	17,700
Research and development expense	146,600	$ 167,200
Receivable from former parent	$ 5,500

Share-Based Compensation - Summary of Assumption Estimate Fair Value of Stock Options Granted (Details)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement, Noncash Expense [Abstract]
Risk-free interest rate	4.10%
Dividend rate	0.00%
Expected volatility	87.10%
Expected life (years)	6 years 10 days

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Schedule of Number of Ordinary Shares Underlying Potentially Dilutive Securities

As of December 31, 2023 and 2022, the number of ordinary shares underlying potentially dilutive securities consist of:


	December 31,
	2023		2022
Options to purchase ordinary shares		3,348,715		—
Restricted share units		1,129,512		—
Total		4,478,227		—

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Summary of Loss Before the Provision for Income Taxes by Geographical Area

The distribution of the Company’s loss before the provision for income taxes by geographical area consists of the following:


	Year Ended December 31,
(in thousands)	2023			2022
Ireland	$	(187,172	)	$	(178,693	)
U.S.		(8,115	)		(6,230	)
Loss before the provision for income taxes	$	(195,287	)	$	(184,923	)

Summary Of Provision For Income Taxes

The provision for income taxes consists of the following:


	Year Ended December 31,
(in thousands)	2023		2022
Current income tax provision:
U.S. federal	$	12,138	$	4,858
U.S. state	22			26
Ireland		—		—
Deferred income tax provision:
U.S. federal		—		—
U.S. state		—		—
Ireland		—		—
Total tax provision	$	12,160	$	4,884

Components of Net Deferred Tax Assets (Liabilities)

The components of the net deferred tax assets (liabilities) of the Company consist of the following:


(in thousands)	December 31, 2023			December 31, 2022
Deferred tax assets:
Net operating losses	$	714		$	72,973
Tax credits		584			7,074
Accrued expenses		920			361
Research and development expenses		2,755			31,866
Lease liability		3,156			4,075
Share-based compensation		1,123			2,570
Other		—			3,451
Less: valuation allowance		(5,929	)		(117,475	)
Total deferred tax assets	$	3,323		$	4,895
Deferred tax liabilities:
Right-of-use assets		(2,680	)		(3,851	)
Property and equipment		(643	)		(1,044	)
Total deferred tax liabilities	$	(3,323	)	$	(4,895	)
Net deferred tax assets	$	—		$	—

Summary of Activity in Valuation Allowance Associated with Deferred Taxes

The activity in the valuation allowance associated with deferred taxes consists of the following:


(in thousands)	Balance at Beginning of Period			(Additions) or Reductions (1)			Balance at End of Period
Deferred tax asset valuation allowance for the year ended December 31, 2022	$	(74,131	)	$	(43,344	)	$	(117,475	)
Deferred tax asset valuation allowance for the year ended December 31, 2023	$	(117,475	)	$	111,546		$	(5,929	)

(1)

The additions in the year December 31, 2022 related primarily to Irish NOLs for which no benefit is recognized. The reductions in the year ended December 31, 2023 relate primarily to tax attributes forfeited to the Former Parent as part of the Separation.

Reconciliation of Statutory Tax Rate Effective Tax Rate

A reconciliation of the Company’s statutory tax rate to its effective tax rate is as follows:


	Year Ended December 31,
(in thousands, except percentage amounts)	2023			2022
Statutory tax rate		21.0	%		21.0	%
Income tax provision at statutory rate	$	(41,089	)	$	(38,834	)
Foreign rate differential(1)		14,982			10,834
Change in valuation allowance		50,151			43,344
U.S. state income taxes, net of U.S. federal benefit		(85	)		(11	)
Non-deductible share-based compensation		3,680			267
Foreign derived intangible income		(10,581	)		(6,750	)
R&D credit		(4,990	)		(4,489	)
Other		(9	)		—
Permanent items		101			523
Income tax provision	$	12,160		$	4,884
Effective tax rate		(6.1	)%		(2.6	)%

(1)

Represents income or losses of the Company’s Irish parent, subject to tax at a rate other than the U.S. statutory rate.

Reconciliation of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:


(in thousands)	Unrecognized Tax Benefits
Balance, December 31, 2021	$	1,784
Additions based on tax positions related to the current period		348
Balance, December 31, 2022	$	2,132
Subtractions based on tax positions related to the prior period		(2,132	)
Balance, December 31, 2023	$	—

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Dec. 31, 2023
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	During the fourth quarter of 2023, Vicki Goodman, our Chief Medical Officer and Maiken Keson-Brookes, our Chief Legal Officer, each entered into a Rule 10b5-1 trading arrangement that is intended to qualify as an “eligible sell-to-cover transaction” (as described in Rule 10b5-1(c)(1)(ii)(D)(3) under the Exchange Act). These sell-to-cover arrangements, which were adopted on December 21, 2023 and December 22, 2023, respectively, apply to restricted stock units (“RSUs”), whether vesting is based on the passage of time and/or the achievement of performance goals, granted on December 14, 2023, and any RSUs that may be granted from time to time thereafter (other than those which by their terms require us to withhold shares for tax withholding obligations in connection with vesting and settlement). These arrangements provide for the automatic sale of ordinary shares that would otherwise be issuable on each settlement date of a covered RSU in an amount necessary to satisfy the applicable withholding obligation, with the proceeds of the sale delivered to us in satisfaction of the applicable withholding obligation. The number of ordinary shares that will be sold under these arrangements is not currently determinable as the number will vary based on the extent to which vesting conditions are satisfied, the market price of our ordinary shares at the time of settlement and the potential future grant of additional RSUs subject to this arrangement.
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Vicki Goodman
Trading Arrangements, by Individual
Name	Vicki Goodman
Title	Chief Medical Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 21, 2023
Maiken Keson-Brookes
Trading Arrangements, by Individual
Name	Maiken Keson-Brookes
Title	Chief Legal Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 22, 2023

Subsequent Events - Additional Information (Details) - USD ($) $ in Millions	Jan. 12, 2024	Jan. 03, 2024	Dec. 31, 2023
Parent
Subsequent Event [Line Items]
Letter of credit security deposit			$ 1.9
Subsequent Event \| Letter of Credit for Winter Street Lease
Subsequent Event [Line Items]
Letter of credit		$ 1.7
Subsequent Event \| Parent \| Letter of Credit for Winter Street Lease
Subsequent Event [Line Items]
Letter of credit security deposit		$ 1.9
Subsequent Event \| 2024 Inducement Stock Option and Incentive Plan \| Maximum
Subsequent Event [Line Items]
Granted shares of ordinary shares	300,000

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References + Details

Fair Value (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Financial Assets Measured and Recognized at Fair Value on a Recurring Basis


(in thousands)	December 31, 2023		Level 1		Level 2		Level 3
Assets:
Money market mutual funds in cash equivalents	$	268,720	$	268,720	$	—	$	—
Total	$	268,720	$	268,720	$	—	$	—

Subsequent Events

12 Months Ended

Dec. 31, 2023

Subsequent Events [Abstract]

Subsequent Events

13. Subsequent Events

On January 3, 2024, the Company entered into a $1.7 million collateralized letter of credit that secures the obligations of the tenant under the Winter Street Lease. This letter of credit is intended to replace the $1.9 million Letter of Credit maintained by the Former Parent for this purpose.

On January 12, 2024, the Company’s Board of Directors adopted the 2024 Inducement Stock Option and Incentive Plan (the “Inducement Plan”), which provides for the issuance of up to 300,000 ordinary shares as stock options, share appreciation rights, restricted share awards, restricted share units, unrestricted share awards, and dividend equivalent rights. Awards under the Inducement Plan may only be granted to persons who (a) were not previously an employee or director of the Company or (b) are commencing employment with the Company following a bona fide period of non-employment with the Company, in either case as an inducement material to the individual’s entering into employment with the Company and in accordance with the requirements of Nasdaq Stock Market Rule 5635(c)(4).

Restructuring

12 Months Ended

Dec. 31, 2023

Restructuring Charges [Abstract]

Restructuring

12. Restructuring

On July 12, 2023, in conjunction with the Former Parent's ongoing review of operations and the planned separation of the oncology business, the Former Parent executed a restructuring plan, which included the elimination of certain positions that were intended to transition to the Company (the “Restructuring”). Of the charge the Former Parent recorded in the year ended December 31, 2023 as a result of the Restructuring, $1.6 million was attributable to the Company. Such charge consists of one-time termination benefits for employee severance, benefits and related costs, all of which were expected to result in cash expenditures by the Former Parent, and substantially all of which were paid by the Former Parent as of September 30, 2023. Substantially all of the charge related to the Restructuring was included in research and development expenses in the Company’s consolidated statements of operations and comprehensive loss for the year ended December 31, 2023.

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2023	Mar. 15, 2024
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-41837
Entity Registrant Name	Mural Oncology plc
Entity Central Index Key	0001971543
Entity Incorporation, State or Country Code	L2
Entity Tax Identification Number	98-1748617
Entity Address, Address Line One	10 Earlsfort Terrace
Entity Address, City or Town	Dublin 2
Entity Address, Country	IE
Entity Address, Postal Zip Code	D02 T380
City Area Code	353
Local Phone Number	1-905-8020
Title of 12(b) Security	Ordinary shares, nominal value $0.01 per share
Trading Symbol	MURA
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float		$ 81,397,466
Entity Common Stock, Shares Outstanding		16,922,550
Documents Incorporated by Reference [Text Block]	DOCUMENTS INCORPORATED BY REFERENCE The registrant intends to file a definitive proxy statement pursuant to Regulation 14A relating to the 2024 Annual General Meeting of Shareholders within 120 days of the end of the registrant’s fiscal year ended December 31, 2023. Portions of such definitive proxy statement are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein.
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Boston, Massachusetts
Auditor Firm ID	238

Leases - Summary of Effect of Lease Costs in Consolidated Statements of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating lease cost	$ 5,799	$ 6,202
Variable lease cost	4,921	3,618
Total lease costs	$ 10,720	$ 9,820

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred shares, par value	$ 0.01	$ 0.01
Preferred shares, shares authorized	50,000,000	50,000,000
Preferred shares, shares issued	0	0
Preferred shares, shares outstanding	0	0
Ordinary shares, par value	$ 0.01	$ 0.01
Ordinary shares, shares authorized	450,000,000	450,000,000
Ordinary shares, shares issued	16,689,740	0
Ordinary shares, shares outstanding	16,689,740	0

Share-Based Compensation - Summary of Restricted Share Activity (Details) - 2023 Plan - Restricted Stock Units	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Aggregate impact of conversion related to the Separation, Number of Shares \| shares	863,787
Granted, Number of Shares \| shares	265,725
Unvested outstanding at December 31, 2023 \| shares	1,129,512
Aggregate impact of conversion related to the Separation, weighted-average grant date fair value per share \| $ / shares	$ 4.71
Granted, weighted-average grant date fair value per share \| $ / shares	3.61
Unvested outstanding at December 31, 2023, Weighted-Average Grant Date Fair Value Per Share \| $ / shares	$ 4.45

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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+ Details

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating expenses
Research and development	$ 165,532	$ 167,191
General and administrative	30,706	17,732
Total operating expenses	196,238	184,923
Operating loss	(196,238)	(184,923)
Other income (expense), net	951
Income tax provision	(12,160)	(4,884)
Net loss and comprehensive loss	$ (207,447)	$ (189,807)
Net loss per share - basic	$ (12.43)	$ (11.37)
Net loss per share - diluted	$ (12.43)	$ (11.37)
Weighted average common shares used in computing net loss per share - basic	16,689,740	16,689,740
Weighted average common shares used in computing net loss per share - diluted	16,689,740	16,689,740

Income Taxes - Summary of Activity in Valuation Allowance Associated with Deferred Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Valuation Allowance [Abstract]
Balance at Beginning of Period	$ (117,475)	$ (74,131)
(Additions) or Reductions	111,546	(43,344)
Balance at End of Period	$ (5,929)	$ (117,475)

Accrued Expenses

12 Months Ended

Dec. 31, 2023

Payables and Accruals [Abstract]

Accrued Expenses

4. Accrued Expenses

Accrued expenses consisted of the following:


(in thousands)	December 31, 2023		December 31, 2022
Accrued compensation	$	5,858	$	7,104
Accrued external research and development services		8,543		25,298
Accrued general and administrative		2,545		302
Accrued other		—		46
Total accrued expenses	$	16,946	$	32,750

The decrease in accrued expenses as of December 31, 2023 compared to December 31, 2022 is primarily due to the timing of invoice payments around the date of the Separation.

Income Taxes - Reconciliation of Statutory Tax Rate to Effective Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory tax rate	21.00%	21.00%
Income tax provision at statutory rate	$ (41,089)	$ (38,834)
Foreign rate differential	14,982	10,834
Change in valuation allowance	50,151	43,344
U.S. state income taxes, net of U.S. federal benefit	(85)	(11)
Non-deductible share-based compensation	3,680	267
Foreign derived intangible income	(10,581)	(6,750)
R&D credit	(4,990)	(4,489)
Other	(9)	0
Permanent items	101	523
Total tax provision	$ 12,160	$ 4,884
Effective tax rate	(6.10%)	(2.60%)

Fair Value

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Fair Value

. Fair Value

The following table presents information about the Company’s financial assets measured and recognized at fair value on a recurring basis classified under the appropriate level of the fair value hierarchy as of December 31, 2023. The Company had no financial assets measured and recognized at fair value as of December 31, 2022.


(in thousands)	December 31, 2023		Level 1		Level 2		Level 3
Assets:
Money market mutual funds in cash equivalents	$	268,720	$	268,720	$	—	$	—
Total	$	268,720	$	268,720	$	—	$	—

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Net Loss Per Share - Additional Information (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Nov. 15, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Distribution of ordinary shares	16,689,740	0
Dilutive equity instruments	4,478,227	0
Equity awards	0
Alkermes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Distribution of ordinary shares			16,689,740

Leases (Tables)

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Summary of Effect of Lease Costs in Consolidated Statements of Operations and Comprehensive Loss

The following table summarizes the effect of lease costs in the Company’s consolidated statements of operations and comprehensive loss:


	Year Ended December 31,
(in thousands)	2023		2022
Operating lease cost	$	5,799	$	6,202
Variable lease cost		4,921		3,618
Total lease cost	$	10,720	$	9,820

Schedule of Future Lease Payments under Non-cancelable Leases

Future lease payments under non-cancelable leases as of December 31, 2023 consisted of the following:


(in thousands)	December 31, 2023
2024	$	6,496
2025		6,642
2026		2,484
Total operating lease payments	$	15,622
Less: imputed interest		(613	)
Total operating lease liabilities	$	15,009

Accrued Expenses - Components of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued compensation	$ 5,858	$ 7,104
Accrued external research and development services	8,543	25,298
Accrued general and administrative	2,545	302
Accrued other	0	46
Total accrued expenses	$ 16,946	$ 32,750

Leases

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Leases

5. Leases

The Company’s only lease as of December 31, 2023 and 2022 was an operating lease for approximately 180,000 square feet of corporate office space, administrative areas and laboratories at 850 and 852 Winter Street in Waltham, Massachusetts, which includes 34,000 square feet of laboratory space (as amended, the “Winter Street Lease”). Under the terms of the Winter Street Lease, the Company also has the ability to sub-lease its corporate office and laboratory space. The original lease commenced in 2010 and was extended, at the Former Parent’s option, for approximately five years in 2020. The lease extension commenced in March 2021 for approximately 163,000 square feet of space and in September 2021 for the remaining approximately 17,000 square feet of space. The Winter Street Lease expires in 2026 and includes a tenant option to extend the term of the lease for an additional five-year period, which the Company is not reasonably certain to exercise. The Winter Street Lease was assigned to the Company in connection with the Separation and is used solely for operations of the Company. The Former Parent has been primarily obligated to the landlord for the Winter Street Lease, and, following the Separation, the Former Parent is jointly and severally liable with the Company for, and continues to guarantee, all obligations under the Winter Street Lease. As of December 31, 2023, the Former Parent is the applicant with respect to the letter of credit security deposit that secures the obligations of the tenant under the Winter Street Lease. The Former Parent maintains a $1.9 million collateralized letter of credit (the “Letter of Credit”) related to such security deposit as of December 31, 2023. As the Company did not have legal ownership over any bank accounts prior to the Separation, there were no cash or cash equivalents balances specifically attributable to the Company for the periods prior to the Separation and, accordingly, no amount is reflected in the consolidated financial statements related to the Letter of Credit. See Note 13, Subsequent Events, for additional information on the letter of credit agreement that the Company entered into subsequent to December 31, 2023.

As of December 31, 2023 and 2022, the incremental borrowing rate for the Winter Street Lease was 3.52%. As of December 31, 2023, the remaining term for the operating lease was 2.8 years. During the years ended December 31, 2023 and 2022, cash paid by the Company and, prior to the Separation, by the Former Parent, for amounts included for the measurement of lease liabilities was $6.4 million and $6.2 million, respectively, and are included within cash flows from operating activities.

The following table summarizes the effect of lease costs in the Company’s consolidated statements of operations and comprehensive loss:


	Year Ended December 31,
(in thousands)	2023		2022
Operating lease cost	$	5,799	$	6,202
Variable lease cost		4,921		3,618
Total lease cost	$	10,720	$	9,820

Future lease payments under non-cancelable leases as of December 31, 2023 consisted of the following:


(in thousands)	December 31, 2023
2024	$	6,496
2025		6,642
2026		2,484
Total operating lease payments	$	15,622
Less: imputed interest		(613	)
Total operating lease liabilities	$	15,009

Share-Based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Share-Based Compensation

6. Share-Based Compensation

2023 Stock Option and Incentive Plan

The Company’s 2023 Stock Option and Incentive Plan (the “2023 Plan”), which became effective on October 30, 2023, provides for the grant of up to 5,000,000 of the Company’s ordinary shares. The 2023 Plan allows the Company to make equity-based and cash-based incentive awards such as stock options, share appreciation rights, RSU awards, RSUs, unrestricted share awards, cash-based awards, and dividend equivalent rights to officers, employees, non-employee directors, and consultants, subject to the provisions of the 2023 Plan. The 5,000,000 shares provided for by the 2023 Plan include both new awards and awards that were converted to awards of the Company (“Converted Awards”) from awards previously granted under the Parent’s

share-based compensation plans according to the employee matters agreement. See the section entitled “Converted Awards” below for additional information on Converted Awards and the employee matters agreement.

The 2023 Plan is administered by the Company’s Board of Directors, which may in turn delegate authority to administer the plan to a committee of the Board of Directors or an officer of the Company, referred to herein as the 2023 Plan Administrator. Subject to the terms of the 2023 Plan, the 2023 Plan Administrator has the authority to determine recipients, the number of shares or amount of cash subject to awards to be granted, the type of award, and the terms and conditions of the awards, including the exercise period and vesting terms. The fair market value of the shares on any given date is determined in good faith by the 2023 Plan Administrator; provided, however, that if the shares are listed on a national securities exchange or traded on any established market, the determination is made by reference to the closing price on such date. If there is no closing price for such date, the determination is made by reference to the last date preceding such date for which there is a closing price.

Option awards must be granted with an exercise price per ordinary share at least equal to the fair value of one ordinary share on the date of grant. The term of each option award will be fixed by the 2023 Plan Administrator and may not exceed 10 years from the date of grant. Stock options granted generally vest over a four-year period, with 25% vesting on the one-year anniversary of the grant date and the remaining 75% vesting quarterly over the remaining three years, assuming continued service, and with vesting acceleration in full immediately prior to a change in control. RSUs generally vest and are settled over a four-year period, with 25% vesting and settling upon each of the first four anniversaries of the grant date.

The 2023 Plan provides that the number of shares reserved and available for issuance under the 2023 Plan will be automatically increased on January 1, 2025, and each January 1 thereafter, in an amount equal to (i) 5% of the outstanding number of the Company’s ordinary shares on the immediately preceding December 31, or (ii) such lesser number of shares as determined by the 2023 Plan Administrator. The ordinary shares underlying any awards under the 2023 Plan that are forfeited, cancelled or held back upon exercise of settlement of an award to satisfy the exercise price or any tax withholding obligation, or are otherwise terminated or forfeited (other than by exercise) will be added back to the ordinary shares available for issuance under the 2023 Plan. At December 31, 2023, 521,733 ordinary shares were reserved and available for issuance under the 2023 Plan.

2023 Employee Stock Purchase Plan

The Company’s 2023 Employee Stock Purchase Plan (the “ESPP”) became effective on October 30, 2023. The ESPP is administered by the Company’s Board of Directors, which may in turn delegate authority to administer the plan to a committee of the Board of Directors or an officer of the Company. The ESPP initially reserves and authorizes the issuance of up to a total of 100,000 of the Company’s ordinary shares to participating employees. The ESPP provides that the number of shares reserved and available for issuance will automatically increase on January 1, 2025 and each January 1 thereafter through January 1, 2034, by the least of (i) 100,000 ordinary shares, (ii) 1% of the outstanding number of ordinary shares on the immediately preceding December 31, or (iii) such lesser number of ordinary shares as determined by the administrator of the ESPP. The number of shares reserved under the ESPP is subject to adjustment in the event of a share split, share dividend, or other change in the Company’s capitalization.

Converted Awards

On November 13, 2023, the Company entered into the employee matters agreement with the Former Parent under which the Company agreed to convert all outstanding Former Parent stock options and RSUs held by the Company’s employees under the Former Parent’s share-based compensation plans into the Company stock options and RSU under the 2023 Plan in accordance with the conversion ratio set forth in the agreement. On December 14, 2023, the Former Parent and the Company amended the employee matters agreement to adjust the conversion ratio used to calculate the number of the Company’s RSUs issuable to each employee in exchange for each RSU of Alkermes. All outstanding equity awards held by the Company’s employees were converted and issued under the 2023 Plan in December 2023 in accordance with the amended employee matters agreement. Except for the number of underlying shares and the exercise price of the stock options, the converted awards retain substantially the same terms and conditions of the original awards, including their term and vesting conditions.

The obligation to issue replacement awards to the Company’s employees was accounted for as a modification to the original awards at the time of the Separation. The Company compared the fair value of the awards immediately before and after the Separation, resulting in incremental fair value of approximately $9.4 million. As the terms of the original employee matters agreement would have required the Company to issue approximately 8.5 million share awards to 83 employees, or 3.5 million share awards above the 5.0 million shares available for issuance under the 2023 plan, the 3.5 million shares subject to RSUs and options were accounted for as liability-classified awards and remeasured through the date on which the employee matters agreement was amended. The remeasurement of these awards resulted in the reduction of the incremental fair value associated with the modified awards of approximately $5.2 million. Of the remaining $4.2 million of incremental fair value, approximately $0.6 million was recognized immediately with the remainder to be expensed over the remaining service period. As the amendment to the employee matters agreements resulted in a decrease in the number of RSUs to be issued, no significant

incremental compensation cost was incurred. The Company recorded accelerated amortization of approximately $7.3 million associated with options and RSUs that were treated as surrendered by the employees for accounting purposes in connection with the amendment to the employee matters agreement.

Former Parent Share-based Compensation Plans

The Parent has share-based compensation plans which provide for granting equity awards, including non-qualified and incentive stock options, RSUs, RSU awards, cash-based awards, and performance shares to employees, officers and directors of, and consultants to, the Former Parent. Prior to the Separation, all share-based compensation plans were managed on a consolidated basis by the Former Parent and share-based compensation expense was allocated to the Company related to stock options, time-based RSU awards and performance-based RSU awards issued by the Former Parent. Accordingly, the amounts presented are not necessarily indicative of future share-based compensation and do not necessarily reflect the amount that the Company would have issued as an independent company for the periods presented.

Stock Plan Activity

The following average assumptions were used to estimate the fair value of stock options granted by Mural following the Separation using the Black-Scholes option pricing model:


	Year Ended December 31, 2023
Risk-free interest rate		4.1	%
Dividend rate		0	%
Expected volatility		87.1	%
Expected life (years)		6.03

A summary of stock option activity under the 2023 Plan for the year ended December 31, 2023 is as follows:


	Number of Options		Weighted-Average Exercise Price
Options outstanding at December 31, 2022		—	$	—
Aggregate impact of conversion related to the Separation		2,756,173	$	4.73
Granted		592,542	$	3.61
Options outstanding at December 31, 2023		3,348,715	$	4.53
Options exercisable at December 31, 2023		741,936	$	4.97

A summary of RSU activity under the 2023 Plan for the year ended December 31, 2023 is as follows:


	Number of Shares		Weighted-Average Grant Date Fair Value Per Share
Unvested outstanding at December 31, 2022		—	$	—
Aggregate impact of conversion related to the Separation		863,787	$	4.71
Granted		265,725	$	3.61
Unvested outstanding at December 31, 2023		1,129,512	$	4.45

At December 31, 2023, there was $3.8 million of unrecognized share-based compensation expense related to unvested RSUs, which will be recognized over a weighted average remaining contractual term of 1.6 years.

The following table represents share-based compensation expense included in the Company’s consolidated statements of operations and comprehensive loss:


	Year Ended December 31,
(in thousands)	2023		2022
Research and development	$	11,550	$	9,515
General and administrative		12,559		2,416
Total share-based compensation expense	$	24,109	$	11,931

Basis of Presentation and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Basis of Presentation

Use of Estimates

Cash and Cash Equivalents and Restricted Cash

At December 31, 2023, the Company also had a long-term restricted cash balance of $0.3 million for cash restricted for use pertaining to corporate credit cards.

Fair Value Measurements

•

Level 1—Quoted prices in active markets for identical assets or liabilities.

•

Receivable from Former Parent

Property and Equipment


Asset group		Term
Furniture, fixtures and equipment		3 - 10 years
Leasehold improvements		Shorter of useful life or lease term

Leases

Impairment of Long-Lived Assets

Research and Development Expenses

Clinical Trial and Preclinical Study Expenses

General and Administrative Expenses

Share-Based Compensation

Income Taxes

Comprehensive Loss and Loss per Share

Basic net loss per share is computed by dividing the net loss in each period by the weighted average number of ordinary shares outstanding during such period. Diluted net loss per share is computed similarly to basic net loss per share except that the denominator is increased to include the number of additional ordinary shares that would have been outstanding if the potential ordinary shares had been issued and if the additional ordinary shares were dilutive. For the periods presented, ordinary share equivalents, consisting of share-based awards, were not included in the calculation of the diluted net loss per share because to do so would be anti-dilutive. The number of shares distributed to the Former Parent’s shareholders of record on the effective date of the Distribution was used for the calculation of basic and diluted earnings per share for periods prior to the Separation as the Company had no shares outstanding prior to the Separation.

Segment Information

401(k) Plan

Recently Issued Accounting Pronouncements

Income Taxes - Components of Net Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating losses	$ 714	$ 72,973
Tax credits	584	7,074
Accrued expenses	920	361
Research and development expenses	2,755	31,866
Lease liability	3,156	4,075
Share-based compensation	1,123	2,570
Other	0	3,451
Less: valuation allowance	(5,929)	(117,475)
Total deferred tax assets	3,323	4,895
Deferred tax liabilities:
Right-of-use assets	(2,680)	(3,851)
Property and equipment	(643)	(1,044)
Total deferred tax liabilities	(3,323)	(4,895)
Net deferred tax assets	$ 0	$ 0

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2023

Payables and Accruals [Abstract]

Components of Accrued Expenses

Accrued expenses consisted of the following:


(in thousands)	December 31, 2023		December 31, 2022
Accrued compensation	$	5,858	$	7,104
Accrued external research and development services		8,543		25,298
Accrued general and administrative		2,545		302
Accrued other		—		46
Total accrued expenses	$	16,946	$	32,750

The decrease in accrued expenses as of December 31, 2023 compared to December 31, 2022 is primarily due to the timing of invoice payments around the date of the Separation.

Share-Based Compensation - Additional Information (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) Employee $ / shares shares	Dec. 31, 2022 USD ($)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock authorized for issuance \| shares	5,000,000
Incremental fair value, over remaining service period \| $	$ 600
Share-based compensation \| $	$ 24,109	$ 11,931
Weighted-average grant date fair value of options \| $ / shares	$ 2.69
Stock options vested or expected to vest \| shares	3,100,000
Weighted average exercise price \| $ / shares	$ 4.53
Weighted average contractual remaining life	6 years 1 month 6 days
Weighted average aggregate intrinsic value \| $	$ 4,400
Aggregate intrinsic value of stock options exercisable \| $	$ 700
Exercisable weighted average remaining contractual term	4 years 2 months 12 days
2023 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock authorized for issuance \| shares	5,000,000
Options contractual term	10 years
Share-based compensation arrangement by share-based payment award, description	The 2023 Plan provides that the number of shares reserved and available for issuance under the 2023 Plan will be automatically increased on January 1, 2025, and each January 1 thereafter, in an amount equal to (i) 5% of the outstanding number of the Company’s ordinary shares on the immediately preceding December 31, or (ii) such lesser number of shares as determined by the 2023 Plan Administrator.
Percentage of outstanding our common stock	5.00%
Ordinary shares reserved and available for issuance \| shares	521,733
2023 Plan \| Tranche One
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	4 years
Vesting percentage	25.00%
2023 Plan \| Tranche Two
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	3 years
Vesting percentage	75.00%
Common Stock \| 2023 Employee Stock Purchase Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Percentage of outstanding our common stock	1.00%
Maximum \| 2023 Employee Stock Purchase Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock authorized for issuance \| shares	100,000
Minimum \| 2023 Employee Stock Purchase Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of common stock authorized for issuance \| shares	100,000
Awards to Employees \| Tranche One
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	4 years
Vesting percentage	25.00%
Awards to Employees \| Tranche Two
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	3 years
Vesting percentage	75.00%
Options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized share-based compensation expense \| $	$ 4,300
Unvested stock options weighted average period	2 years
Restricted Stock Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Incremental fair value \| $	$ 7,300
Unrecognized share-based compensation expense \| $	$ 3,800
Unvested stock options weighted average period	1 year 7 months 6 days
Restricted Stock Units \| 2023 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	4 years
Vesting percentage	25.00%
Restricted Stock Units \| Options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares available for issuance \| shares	3,500,000
Converted Awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Incremental fair value \| $	$ 9,400
Reduction in incremental fair value \| $	5,200
Remaining incremental fair value \| $	$ 4,200
Excess shares available for issuance \| shares	3,500,000
Converted Awards \| 2023 Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares available for issuance \| shares	5,000,000
Converted Awards \| Awards to Employees
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Awards issued \| shares	8,500,000
Share awards issued to number of employees \| Employee	83

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Subtotal	$ 45,086	$ 41,969
Less: accumulated depreciation	(33,683)	(31,352)
Total property and equipment, net	11,403	10,617
Furniture, Fixtures and Equipment
Property, Plant and Equipment [Line Items]
Subtotal	21,738	17,470
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Subtotal	23,333	22,510
Construction in Progress
Property, Plant and Equipment [Line Items]
Subtotal	$ 15	$ 1,989

Leases - Additional Information (Details) $ in Millions	1 Months Ended		12 Months Ended
Leases - Additional Information (Details) $ in Millions	Sep. 30, 2021 ft²	Mar. 31, 2021 ft²	Dec. 31, 2023 USD ($) ft²	Dec. 31, 2022 USD ($) ft²
Lessee, Lease, Description [Line Items]
Area of Land \| ft²	17,000	163,000	180,000	180,000
Lease commenced year			2010
Operating leases, options to extend leases term			5 years
Extended lease commenced month and year	2021-09	2021-03
Lease expiration year			2026
Incremental borrowing rate			3.52%	3.52%
Remaining lease term			2 years 9 months 18 days
Laboratory Space
Lessee, Lease, Description [Line Items]
Area of Land \| ft²			34,000
Parent
Lessee, Lease, Description [Line Items]
Letter of credit security deposit \| $			$ 1.9
Cash paid for amounts included for measurement of lease liabilities \| $			$ 6.4	$ 6.2

Income Taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Income Taxes

7. Income Taxes

Prior to the Separation, the Company was included in the income tax returns filed by the Former Parent. In preparing the historical combined financial statements for the Company for periods prior to the Separation, the Former Parent determined the tax provision for those operations on a separate return basis. The tax provision and the related tax disclosures set out below are not necessarily representative of the tax provision and the related tax disclosures that may arise in the future.

The distribution of the Company’s loss before the provision for income taxes by geographical area consists of the following:


	Year Ended December 31,
(in thousands)	2023			2022
Ireland	$	(187,172	)	$	(178,693	)
U.S.		(8,115	)		(6,230	)
Loss before the provision for income taxes	$	(195,287	)	$	(184,923	)

The provision for income taxes consists of the following:


	Year Ended December 31,
(in thousands)	2023		2022
Current income tax provision:
U.S. federal	$	12,138	$	4,858
U.S. state	22			26
Ireland		—		—
Deferred income tax provision:
U.S. federal		—		—
U.S. state		—		—
Ireland		—		—
Total tax provision	$	12,160	$	4,884

The income tax provisions during the years December 31, 2023 and 2022 were primarily due to U.S. current income tax expense payable by the Former Parent as a result of the required capitalization of and the amortization of R&D expenses in accordance with Section 174 of the Internal Revenue Code of 1986.

No provision for income tax has been provided on undistributed earnings of the U.S. subsidiaries because such earnings are indefinitely reinvested in the U.S. operations. As of December 31, 2023, the Company had no unremitted earnings that were indefinitely reinvested related to its consolidated U.S. subsidiaries.

The components of the net deferred tax assets (liabilities) of the Company consist of the following:


(in thousands)	December 31, 2023			December 31, 2022
Deferred tax assets:
Net operating losses	$	714		$	72,973
Tax credits		584			7,074
Accrued expenses		920			361
Research and development expenses		2,755			31,866
Lease liability		3,156			4,075
Share-based compensation		1,123			2,570
Other		—			3,451
Less: valuation allowance		(5,929	)		(117,475	)
Total deferred tax assets	$	3,323		$	4,895
Deferred tax liabilities:
Right-of-use assets		(2,680	)		(3,851	)
Property and equipment		(643	)		(1,044	)
Total deferred tax liabilities	$	(3,323	)	$	(4,895	)
Net deferred tax assets	$	—		$	—

Note that the net deferred tax assets presented in the table above and the tax attributes referred to below for the periods prior to the Separation were calculated based on the separate return method and do not represent the net deferred tax assets or tax attributes that transferred with the Company at the Separation.

The activity in the valuation allowance associated with deferred taxes consists of the following:


(in thousands)	Balance at Beginning of Period			(Additions) or Reductions (1)			Balance at End of Period
Deferred tax asset valuation allowance for the year ended December 31, 2022	$	(74,131	)	$	(43,344	)	$	(117,475	)
Deferred tax asset valuation allowance for the year ended December 31, 2023	$	(117,475	)	$	111,546		$	(5,929	)

(1)

At December 31, 2023, the Company maintained a valuation allowance of $5.9 million against U.S. federal and state deferred tax assets as the Company has determined that it is more-likely-than-not that these net deferred tax assets will not be realized. If the Company demonstrates consistent profitability in the future, the evaluation of the recoverability of these deferred tax assets could change and the valuation allowance may be released in part or in whole.

As of December 31, 2023, the Company had $2.9 million of U.S. federal NOL carryforwards and $0.5 million of federal R&D credits. The NOL carryforwards are indefinite and do not expire,and the R&D credits begin to expire in 2038. These loss and credit carryforwards are available to reduce certain future U.S. taxable income and tax, respectively. These loss and credit carryforwards are subject to review and possible adjustment by the appropriate taxing authorities and may be subject to limitations based upon changes in the ownership of our ordinary shares. The Company has $0.2 million of Irish NOL carryforwards which have an indefinite carryforward.

A reconciliation of the Company’s statutory tax rate to its effective tax rate is as follows:


	Year Ended December 31,
(in thousands, except percentage amounts)	2023			2022
Statutory tax rate		21.0	%		21.0	%
Income tax provision at statutory rate	$	(41,089	)	$	(38,834	)
Foreign rate differential(1)		14,982			10,834
Change in valuation allowance		50,151			43,344
U.S. state income taxes, net of U.S. federal benefit		(85	)		(11	)
Non-deductible share-based compensation		3,680			267
Foreign derived intangible income		(10,581	)		(6,750	)
R&D credit		(4,990	)		(4,489	)
Other		(9	)		—
Permanent items		101			523
Income tax provision	$	12,160		$	4,884
Effective tax rate		(6.1	)%		(2.6	)%

(1)

Represents income or losses of the Company’s Irish parent, subject to tax at a rate other than the U.S. statutory rate.

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:


(in thousands)	Unrecognized Tax Benefits
Balance, December 31, 2021	$	1,784
Additions based on tax positions related to the current period		348
Balance, December 31, 2022	$	2,132
Subtractions based on tax positions related to the prior period		(2,132	)
Balance, December 31, 2023	$	—

In years in which the Company may have unrecognized tax benefits, such unrecognized tax benefits would affect the Company’s effective tax rate prior to taking its valuation allowance into consideration. The Company had no unrecognized tax benefits at December 31, 2023. The Company does not anticipate that the amount of existing unrecognized tax benefits will materially increase or decrease within the next 12 months. Note that the unrecognized tax benefits presented in the table above for the periods prior to the Separation were calculated based on the separate return method and do not represent the unrecognized tax benefits that transferred with the Company at the Separation.

The taxing jurisdictions for the Company include Ireland and the U.S. (federal and state). These jurisdictions have varying statutes of limitations. The tax years beginning in 2023 are open to examination by taxing authorities.

The Company does not have any tax returns filed as of December 31, 2023 nor has it taken any positions that would result in uncertain tax benefits.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details