Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2025
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and follow the requirements of the SEC for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP can be condensed or omitted. The interim condensed balance sheet as of March 31, 2025, the interim condensed statements of operations and comprehensive loss, stockholders’ equity and cash flows for the three months ended March 31, 2025 and 2024 are unaudited. These unaudited interim condensed financial statements have been prepared on the same basis as the Company’s annual financial statements and reflect all adjustments that are necessary for the fair statement of the Company’s financial position, results of operations and cash flows for the interim periods presented. The condensed results of operations for the three months ended March 31, 2025, are not necessarily indicative of the results to be expected for the full year or for any other future annual or interim period. The condensed balance sheet as of December 31, 2024, included herein was derived from the audited financial statements as of that date. These condensed financial statements should be read in conjunction with the Company’s audited financial statements and the related notes thereto for the year ended December 31, 2024, included in the Company’s Annual Report on Form 10-K, filed with the SEC on March 10, 2025.
Use of Estimates	Use of Estimates The preparation of condensed financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and the disclosure of contingent assets and liabilities at the date of the condensed financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying financial statements include, but are not limited to, accrued expenses related to research and development activities. The Company bases its estimates on historical experience, the current economic environment, and on various other assumptions that are believed to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions.
CIRM Grant	CIRM Grant In February 2025, the Company announced it was awarded an $8 million grant from the California Institute for Regenerative Medicine (CIRM) to support the clinical trial of TN-401. The award is payable to the Company upon achievement of certain clinical milestones. Additionally, if CIRM determines, in its sole discretion, that the Company has not complied with the terms and conditions of the grant, CIRM may suspend or permanently cease disbursements. Funds received under this grant may only be used for allowable project costs specifically identified with the CIRM-funded project. Such costs can include, but are not limited to, salary for personnel, itemized supplies, consultants, and itemized clinical study costs. Under the terms of the grant, the Company will co-fund the research project with CIRM and the amount of the Company's co-funding requirement is predetermined as a part of the award. In April 2025, the Company received $0.6 million from CIRM in connection with the grant. The Company will account for the grant under Accounting Standards Codification (ASC) 450-30, Gain Contingencies, and will record the funds against the research and development expenses as it receives them.
Recently Issued Accounting Pronouncements Note Yet Adopted	Recently Issued Accounting Pronouncements Not Yet Adopted In November 2024, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2024-03, Income Statement (Topic 220): Reporting Comprehensive Income - Expense Disaggregation Disclosures, Disaggregation of Income Statement Expenses (ASU 2024-03), which requires public companies to disclose, in interim and annual reporting periods, additional information about certain expenses in the financial statements. The amendments in this ASU will be effective for annual periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is evaluating the impact of this standard on its financial statements and related disclosures. In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (ASU 2023-09), which requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. ASU 2023-09 is effective for annual periods beginning after December 15, 2024. The Company is evaluating the impact of this standard on its financial statements and related disclosures.

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2025

The accompanying condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and follow the requirements of the SEC for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP can be condensed or omitted.

The interim condensed balance sheet as of March 31, 2025, the interim condensed statements of operations and comprehensive loss, stockholders’ equity and cash flows for the three months ended March 31, 2025 and 2024 are unaudited. These unaudited interim condensed financial statements have been prepared on the same basis as the Company’s annual financial statements and reflect all adjustments that are necessary for the fair statement of the Company’s financial position, results of operations and cash flows for the interim periods presented. The condensed results of operations for the three months ended March 31, 2025, are not necessarily indicative of the results to be

expected for the full year or for any other future annual or interim period. The condensed balance sheet as of December 31, 2024, included herein was derived from the audited financial statements as of that date. These condensed financial statements should be read in conjunction with the Company’s audited financial statements and the related notes thereto for the year ended December 31, 2024, included in the Company’s Annual Report on Form 10-K, filed with the SEC on March 10, 2025.

Use of Estimates

The preparation of condensed financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and the disclosure of contingent assets and liabilities at the date of the condensed financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying financial statements include, but are not limited to, accrued expenses related to research and development activities. The Company bases its estimates on historical experience, the current economic environment, and on various other assumptions that are believed to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions.

CIRM Grant

In February 2025, the Company announced it was awarded an $8 million grant from the California Institute for Regenerative Medicine (CIRM) to support the clinical trial of TN-401. The award is payable to the Company upon achievement of certain clinical milestones. Additionally, if CIRM determines, in its sole discretion, that the Company has not complied with the terms and conditions of the grant, CIRM may suspend or permanently cease disbursements. Funds received under this grant may only be used for allowable project costs specifically identified with the CIRM-funded project. Such costs can include, but are not limited to, salary for personnel, itemized supplies, consultants, and itemized clinical study costs. Under the terms of the grant, the Company will co-fund the research project with CIRM and the amount of the Company's co-funding requirement is predetermined as a part of the award. In April 2025, the Company received $0.6 million from CIRM in connection with the grant. The Company will account for the grant under Accounting Standards Codification (ASC) 450-30, Gain Contingencies, and will record the funds against the research and development expenses as it receives them.

Recently Issued Accounting Pronouncements Note Yet Adopted

Recently Issued Accounting Pronouncements Not Yet Adopted

In November 2024, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2024-03, Income Statement (Topic 220): Reporting Comprehensive Income - Expense Disaggregation Disclosures, Disaggregation of Income Statement Expenses (ASU 2024-03), which requires public companies to disclose, in interim and annual reporting periods, additional information about certain expenses in the financial statements. The amendments in this ASU will be effective for annual periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is evaluating the impact of this standard on its financial statements and related disclosures.

In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (ASU 2023-09), which requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. ASU 2023-09 is effective for annual periods beginning after December 15, 2024. The Company is evaluating the impact of this standard on its financial statements and related disclosures.