Summary of Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2026
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The Company’s condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and include the accounts of its consolidated subsidiaries. In comparative periods, where applicable, other shareholders’ interests in the Company’s subsidiaries, Z33 Bio, Inc. (“Z33”) and ZB17 LLC (“ZB17”), are shown in the condensed consolidated financial statements as redeemable noncontrolling interest and noncontrolling interest, respectively. All intercompany balances and transactions have been eliminated in consolidation. These condensed consolidated financial statements are presented in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”) and do not include all disclosures normally required in annual consolidated financial statements prepared in accordance with U.S. GAAP. As such, the information included herein should be read in conjunction with the Company’s consolidated financial statements and accompanying notes as of and for the year ended December 31, 2025 (the “audited consolidated financial statements”) that were included in the Company’s Form 10-K filed with the SEC on March 19, 2026 (the “Annual Report”). In management’s opinion, these condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and reflect all adjustments, which include normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of June 30, 2026 and the results of operations for the three and six months ended June 30, 2026 and 2025. The results of operations for the three and six months ended June 30, 2026 are not necessarily indicative of the results to be expected for the full year ending December 31, 2026 or any other future interim or annual period.
Significant Accounting Policies	Significant Accounting Policies There have been no material changes in the Company’s significant accounting policies from those that were disclosed in Note 2, Summary of Significant Accounting Policies, included in the audited consolidated financial statements in the Company’s Annual Report.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires the Company’s management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, as well as the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Significant estimates and assumptions reflected in the condensed consolidated financial statements relate to and include, but are not limited to, accrued research and development expenses, the fair value of share-based compensation, the fair value of redeemable noncontrolling interest, and the valuation allowance of deferred tax assets resulting from net operating losses.
Risks and Uncertainties	Risks and Uncertainties The Company is subject to risks common to early-stage companies in the biotechnology industry, including, but not limited to, development by the Company or its competitors of technological innovations, risks of failure of clinical studies, dependence on key personnel, protection of proprietary technology, compliance with government regulations, and ability to transition from clinical manufacturing to commercial production of products. The Company’s product candidates will require approvals from the United States Food and Drug Administration (“FDA”) and comparable foreign regulatory agencies prior to commercial sales in their respective jurisdictions. There can be no assurance that any product candidate will receive the necessary approvals. If the Company was denied approval, approval was delayed or the Company was unable to maintain approval for any product candidate, it could have a material adverse impact on the Company. The Company has significant cash balances at financial institutions which throughout the year regularly exceed the federally insured limit of $250,000. Any loss incurred or a lack of access to such funds could have a significant adverse impact on the Company’s financial condition, results of operations, and cash flows.
Segments	Segments Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker (“CODM”) in making decisions regarding resource allocation and assessing performance. The Company’s CODM is the Chief Executive Officer. The Company and the CODM view its operations and manage its business in one operating segment, developing novel medicines for immune and inflammatory disorders. The Company has business activities in different regions that are managed on a consolidated basis. The accounting policies of the Company’s segment are the same as those described within this footnote. The CODM uses net loss, that is reported in the condensed consolidated statements of operations, to assess performance for the Company’s segment and decide how to allocate resources. The measure of segment assets is reported on the condensed consolidated balance sheets as total consolidated assets.
R&D Incentive Credits	R&D Incentive Credits The Company is eligible to obtain certain R&D incentive credits (the “R&D Credits”), through participation in the United Kingdom’s (“U.K.”) R&D Small and Medium Enterprise and the Research and Development Expenditure Credit tax relief programs. The R&D Credits are calculated as a percentage of qualifying R&D expenses incurred as part of research projects. The R&D Credits are used as tax credits for the Company with the resulting amount being payable in cash by the U.K. government (tax authority) to the Company. The R&D Credits are subject to future audits by the U.K. tax authority within defined periods. Although the incentive credits are administered through the local tax authority, the Company has accounted for the incentives outside of the scope of FASB Accounting Standards Codification Topic 740, Income Taxes, since the incentives are not linked to the Company’s taxable income and can be realized regardless of whether the Company has generated taxable income in the respective jurisdictions. The Company accounts for these incentive credits as a government grant which analogizes with International Accounting Standards 20 (“IAS 20”), Accounting for Government Grants and Disclosure of Government Assistance. In accordance with IAS 20, the Company will recognize the R&D Credits when it has reasonable assurance that the R&D Credits will be received. As the Company has only filed two claims under the tax relief programs as of June 30, 2026, it has determined that reasonable assurance will be met upon cash receipt. The Company received the first claim in May 2025. In April 2025, the Company filed a second claim for an R&D Credit for $1.0 million that was received during the three months ended June 30, 2026 and recorded in other income, net within the Company's condensed consolidated statement of operations.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted-average number of the Company's Class A ordinary shares (“Class A Ordinary Shares”) and pre-funded warrants outstanding during the period. The pre-funded warrants are included in the computation of basic and diluted net loss per ordinary share as the exercise price is negligible and the pre-funded warrants are fully vested and exercisable. Basic and diluted net loss per share were the same for each period presented as the inclusion of all potentially dilutive securities outstanding would have been anti-dilutive due to the Company’s net loss.
Income Taxes	Income Taxes Interim income tax provision is calculated in accordance with ASC Topic 270, Interim Reporting, and ASC Topic 740, Accounting for Income Taxes. At the end of each interim period, the Company estimates the annual effective tax rate and applies that rate to the Company's ordinary year to date earnings. In addition, the tax effects of unusual or infrequently occurring items including changes in judgment about valuation allowances and effects of changes in enacted tax laws are recognized discretely in the interim period in which the change occurs. The computation of the annual estimated effective tax rate at each interim period requires certain estimates and significant judgment including the expected operating income for the year, permanent and temporary differences as a result of differences between amounts measured and recognized in accordance with tax laws and financial accounting standards, and the likelihood of recovering deferred tax assets generated in the current fiscal year. The accounting estimates used to compute income tax benefit may change as new events occur, additional information is obtained, or the tax environment changes.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s financial position, results of operations, or cash flows upon adoption. In November 2024, the FASB issued Accounting Standards Update (“ASU”) 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. This ASU requires disclosure in the notes to financial statements of the nature of certain expenses included in the income statement. ASU 2024-03 will be effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating the impact of ASU 2024-03 and expects to adopt it for the year ending December 31, 2027. In December 2025, the FASB issued ASU 2025-10, Government Grants (Topic 832): Accounting for Government Grants Received by Business Entities, which establishes guidance on the recognition, measurement, and presentation of government grants received by business entities. The amendments in ASU 2025-10 are effective for annual reporting periods beginning after December 15, 2028, and interim reporting periods within those annual reporting periods, with early adoption permitted. The guidance can be applied under a modified prospective approach, a modified retrospective approach, or a full retrospective approach. The Company is currently assessing the impact of the adoption of this guidance on its condensed consolidated financial statements and disclosures.

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2026

Basis of Presentation and Principles of Consolidation

The Company’s condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and include the accounts of its consolidated subsidiaries. In comparative periods, where applicable, other shareholders’ interests in the Company’s subsidiaries, Z33 Bio, Inc. (“Z33”) and ZB17 LLC (“ZB17”), are shown in the condensed consolidated financial statements as redeemable noncontrolling interest and noncontrolling interest, respectively. All intercompany balances and transactions have been eliminated in consolidation.

These condensed consolidated financial statements are presented in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”) and do not include all disclosures normally required in annual consolidated financial statements prepared in accordance with U.S. GAAP. As such, the information included herein should be read in conjunction with the Company’s consolidated financial statements and accompanying notes as of and for the year ended December 31, 2025 (the “audited consolidated financial statements”) that were included in the Company’s Form 10-K filed with the SEC on March 19, 2026 (the “Annual Report”). In management’s opinion, these condensed

consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and reflect all adjustments, which include normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of June 30, 2026 and the results of operations for the three and six months ended June 30, 2026 and 2025. The results of operations for the three and six months ended June 30, 2026 are not necessarily indicative of the results to be expected for the full year ending December 31, 2026 or any other future interim or annual period.

Significant Accounting Policies

There have been no material changes in the Company’s significant accounting policies from those that were disclosed in Note 2, Summary of Significant Accounting Policies, included in the audited consolidated financial statements in the Company’s Annual Report.

Use of Estimates

The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires the Company’s management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, as well as the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Significant estimates and assumptions reflected in the condensed consolidated financial statements relate to and include, but are not limited to, accrued research and development expenses, the fair value of share-based compensation, the fair value of redeemable noncontrolling interest, and the valuation allowance of deferred tax assets resulting from net operating losses.

Risks and Uncertainties

The Company is subject to risks common to early-stage companies in the biotechnology industry, including, but not limited to, development by the Company or its competitors of technological innovations, risks of failure of clinical studies, dependence on key personnel, protection of proprietary technology, compliance with government regulations, and ability to transition from clinical manufacturing to commercial production of products.

The Company’s product candidates will require approvals from the United States Food and Drug Administration (“FDA”) and comparable foreign regulatory agencies prior to commercial sales in their respective jurisdictions. There can be no assurance that any product candidate will receive the necessary approvals. If the Company was denied approval, approval was delayed or the Company was unable to maintain approval for any product candidate, it could have a material adverse impact on the Company.

The Company has significant cash balances at financial institutions which throughout the year regularly exceed the federally insured limit of $250,000. Any loss incurred or a lack of access to such funds could have a significant adverse impact on the Company’s financial condition, results of operations, and cash flows.

Segments

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker (“CODM”) in making decisions regarding resource allocation and assessing performance. The Company’s CODM is the Chief Executive Officer. The Company and the CODM view its operations and manage its business in one operating segment, developing novel medicines for immune and inflammatory disorders. The Company has business activities in different regions that are managed on a consolidated basis.

The accounting policies of the Company’s segment are the same as those described within this footnote. The CODM uses net loss, that is reported in the condensed consolidated statements of operations, to assess performance for the Company’s segment and decide how to allocate resources. The measure of segment assets is reported on the condensed consolidated balance sheets as total consolidated assets.

R&D Incentive Credits

The Company is eligible to obtain certain R&D incentive credits (the “R&D Credits”), through participation in the United Kingdom’s (“U.K.”) R&D Small and Medium Enterprise and the Research and Development Expenditure Credit tax relief programs.

The R&D Credits are calculated as a percentage of qualifying R&D expenses incurred as part of research projects. The R&D Credits are used as tax credits for the Company with the resulting amount being payable in cash by the U.K. government (tax authority) to the Company. The R&D Credits are subject to future audits by the U.K. tax authority within defined periods.

Although the incentive credits are administered through the local tax authority, the Company has accounted for the incentives outside of the scope of FASB Accounting Standards Codification Topic 740, Income Taxes, since the incentives are not linked to the Company’s taxable income and can be realized regardless of whether the Company has generated taxable income in the respective jurisdictions. The Company accounts for these incentive credits as a government grant which analogizes with International Accounting Standards 20 (“IAS 20”), Accounting for Government Grants and Disclosure of Government Assistance.

In accordance with IAS 20, the Company will recognize the R&D Credits when it has reasonable assurance that the R&D Credits will be received. As the Company has only filed two claims under the tax relief programs as of June 30, 2026, it has determined that reasonable assurance will be met upon cash receipt. The Company received the first claim in May 2025. In April 2025, the Company filed a second claim for an R&D Credit for $1.0 million that was received during the three months ended June 30, 2026 and recorded in other income, net within the Company's condensed consolidated statement of operations.

Net Loss Per Share

Basic net loss per share is computed by dividing net loss by the weighted-average number of the Company's Class A ordinary shares (“Class A Ordinary Shares”) and pre-funded warrants outstanding during the period. The pre-funded warrants are included in the computation of basic and diluted net loss per ordinary share as the exercise price is negligible and the pre-funded warrants are fully vested and exercisable. Basic and diluted net loss per share were the same for each

period presented as the inclusion of all potentially dilutive securities outstanding would have been anti-dilutive due to the Company’s net loss.

Income Taxes

Interim income tax provision is calculated in accordance with ASC Topic 270, Interim Reporting, and ASC Topic 740, Accounting for Income Taxes. At the end of each interim period, the Company estimates the annual effective tax rate and applies that rate to the Company's ordinary year to date earnings. In addition, the tax effects of unusual or infrequently occurring items including changes in judgment about valuation allowances and effects of changes in enacted tax laws are recognized discretely in the interim period in which the change occurs. The computation of the annual estimated effective tax rate at each interim period requires certain estimates and significant judgment including the expected operating income for the year, permanent and temporary differences as a result of differences between amounts measured and recognized in accordance with tax laws and financial accounting standards, and the likelihood of recovering deferred tax assets generated in the current fiscal year. The accounting estimates used to compute income tax benefit may change as new events occur, additional information is obtained, or the tax environment changes.

Recently Issued Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s financial position, results of operations, or cash flows upon adoption.

In November 2024, the FASB issued Accounting Standards Update (“ASU”) 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. This ASU requires disclosure in the notes to financial statements of the nature of certain expenses included in the income statement. ASU 2024-03 will be effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating the impact of ASU 2024-03 and expects to adopt it for the year ending December 31, 2027.

In December 2025, the FASB issued ASU 2025-10, Government Grants (Topic 832): Accounting for Government Grants Received by Business Entities, which establishes guidance on the recognition, measurement, and presentation of government grants received by business entities. The amendments in ASU 2025-10 are effective for annual reporting

periods beginning after December 15, 2028, and interim reporting periods within those annual reporting periods, with early adoption permitted. The guidance can be applied under a modified prospective approach, a modified retrospective approach, or a full retrospective approach. The Company is currently assessing the impact of the adoption of this guidance on its condensed consolidated financial statements and disclosures.