1. Organization and Description of Business

Mural Oncology plc, an Irish public limited company, and its consolidated subsidiaries (“Mural” or the “Company”) is an oncology company that has 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 developed a portfolio of investigational cytokine therapies designed to address areas of unmet need for patients with a variety of cancers.

On March 25, 2025, the Company announced that, based on the interim analysis of results, its Phase 3 ARTISTRY-7 trial of nemvaleukin alfa (“nemvaleukin”) in combination with pembrolizumab did not achieve its primary endpoint of a statistically significant improvement in overall survival versus investigator’s choice chemotherapy. The Company also announced that ARTISTRY-7 would not continue to final analysis and the Company would cease development of nemvaleukin for platinum resistant ovarian cancer (“PROC”). On April 15, 2025, the Company announced that following review of data from its Phase 2 ARTISTRY-6 trial of nemvaleukin in mucosal and cutaneous melanoma and the previously announced results from the ARTISTRY-7 trial, the Company was discontinuing all clinical development of nemvaleukin and immediately commenced an exploration of strategic alternatives focused on maximizing shareholder value. On June 3, 2025, the Company ceased all remaining development activities on its preclinical programs. See Note 11, Restructuring, for additional information.

The Company was established as a shelf company in May 2017 as a private company limited by shares and was de-shelved in 2023 in connection with the Separation. In August 2023, the legal status of the Company under Irish law was altered to that of a public limited company.

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, Alkermes plc, an Irish public limited company, and its consolidated subsidiaries’ (the “Former Parent” or “Alkermes”) announced its intent, as approved by its board of directors, to explore the separation of the Former Parent’s 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.

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:

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 defined in Note 7, Leases), 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 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 employee 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 “Alkermes Services Agreement”) 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 “Mural Services Agreement”) 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. The Alkermes Services Agreement terminated on March 31, 2025, upon completion of all services to be provided pursuant to this agreement. The Mural Services Agreement terminated on January 31, 2024, upon completion of all services to be provided pursuant to this 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 on November 15, 2023. 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 and Going Concern

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.

Since its inception, the Company has generated operating losses and negative cash flows from operations and expects to continue to incur operating losses and negative cash flows for the foreseeable future. To date, the Company has funded 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 in the fourth quarter of 2023, at the time of the Separation. The Company’s ability to continue development of its product candidates is dependent on its ability to raise additional funding. The Company’s existing cash and cash equivalents of $77.1 million as of June 30, 2025 will not be sufficient to fund continued development of its product candidates and at the same time meet its existing obligations.

In the first quarter of 2025, the Company announced that it would cease development of nemvaleukin for PROC following a review of the interim analysis of the data from its ARTISTRY-7 trial. In the second quarter of 2025, the Company further announced that it would cease all remaining clinical development of nemvaleukin, that it was reducing the Company’s workforce by approximately 90%, and that it would immediately commence the exploration of strategic alternatives focused on maximizing shareholder value. As of June 30, 2025, the Company does not have a strategic alternative under development. See Note 11, Restructuring, for additional information.

The strategic alternatives being explored include, but are not limited to, an offer for acquisition of the Company, merger, business combination, or other transaction. While the Company has not set a timetable for completion of this process, further updates and developments will be disclosed as appropriate or where necessary under regulatory requirements. There can be no assurance that the exploration of strategic alternatives will result in the Company pursuing a transaction or that any acquisition or other transaction involving the Company will be completed, nor as to the terms on which any acquisition or other transaction will occur, 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, as amended (the “Code”), which may limit for a period of time its ability to pursue certain strategic transactions, equity issuances or repurchases or other transactions.

Although following discontinuation of the clinical development of nemvaleukin and the related reduction in force, the Company will have sufficient cash to fund its operations for the next twelve months from the date this Quarterly Report is issued, there can be no assurance that a strategic transaction will be completed and the Company’s board of directors may decide to pursue a dissolution and liquidation of the Company, amongst other alternatives. Due to the inherent uncertainty in the timing and cost of potential strategic alternatives, including impact on its cash consumption, the Company has concluded that as of the date of this Quarterly Report there is substantial doubt about its ability to continue as a going concern. If the Company is unable to raise additional funds when needed or enter into a transaction, the Company may be required to delay, limit, reduce or terminate its strategic process.

The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The condensed consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classifications that may result from the outcome of the uncertainties described above.