Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2026
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The Company’s condensed consolidated financial statements include the accounts of its subsidiaries, Hemab ApS and Hemab Therapeutics, Inc., which was a wholly owned subsidiary of Hemab ApS until April 1, 2026. As a result of the corporate reorganization described in Note 1 “Description of Business and Liquidity—Corporate Reorganization”, Hemab ApS became a wholly owned subsidiary of Hemab Therapeutics Holdings, Inc. and, accordingly, the Company’s consolidated financial statements are those of Hemab Therapeutics Holdings, Inc. for the periods after the corporate reorganization and are those of Hemab ApS for historical periods before the corporate reorganization. Management has concluded the Company has a single reporting segment for purposes of reporting financial condition and results of operations. All intercompany transactions and balances have been eliminated in accordance with ASC 810, Consolidation .
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”).
Unaudited Interim Consolidated Financial Information	Unaudited Interim Consolidated Financial Information The accompanying unaudited condensed consolidated financial statements have been prepared on the same basis as the annual consolidated financial statements of Hemab ApS and reflect, in the opinion of management, all adjustments of a normal and recurring nature that are necessary for the fair statement of the Company’s financial position as of March 31, 2026 and its results of operations and cash flows for the three months ended March 31, 2026 and 2025. The results of operations for the three months ended March 31, 2026 are not necessarily indicative of the results to be expected for the year ending December 31, 2026, or for any other future annual or interim period. The condensed consolidated balance sheet as of December 31, 2025 included herein was derived from the audited financial statements of Hemab ApS as of that date. Certain information and footnote disclosures normally included in consolidated financial statements prepared in accordance with GAAP have been condensed or omitted from these unaudited condensed consolidated financial statements.
Foreign Currency	Foreign Currency The financial statements are presented in U.S. dollars, the Company’s reporting currency. The functional currency of Hemab ApS and Hemab Therapeutics, Inc. is the U.S. dollar. Transaction gains and losses resulting from exchange rate changes on transactions denominated in currencies other than the U.S. dollar are recognized in other (expense) income, net in the consolidated statements of operations and comprehensive loss.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and in these accompanying notes. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors and assumptions that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, which include, but are not limited to, accrued research and development expenses, the fair value of the ordinary shares and warrants for equity-based compensation expense, and the valuation of the Company’s deferred tax assets. Changes in estimates are recorded in the period in which they become known.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk primarily consist of cash, cash equivalents, and marketable securities. The Company’s investment portfolio is primarily comprised of short term debt securities issued by the U.S., Danish, and German governments. The Company places its cash in financial institutions that management believes to be of high credit quality and, consequently, the Company does not believe it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Bank accounts in the United States are insured by the Federal Deposit Insurance Corporation up to $250,000.
Deferred Offering Costs	Deferred Offering Costs Deferred offering costs consist of certain legal, professional, accounting and other third-party fees that are directly associated with the IPO. These direct costs are capitalized and recorded as other non-current assets on the condensed consolidated balance sheets. The deferred offering costs will be recorded against the IPO proceeds upon the consummation of the IPO, which was completed on May 4, 2026. As of March 31, 2026, the Company had $2.7 million of deferred offering costs.
Comprehensive Loss	Comprehensive Loss Comprehensive loss includes net loss as well as other changes in stockholders’ deficit that result from transactions and events other than those with stockholders. The Company’s unrealized gains and losses on available-for sale-debt securities represent the only component of other comprehensive income (loss).
Recently Issued Accounting Standards	Recently Issued Accounting Standards In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”). ASU 2023-09 will require disclosure of additional information in specified categories with respect to the reconciliation of the effective tax rate to the statutory rate (the rate reconciliation) for federal, state and foreign income taxes. ASU 2023-09 will also require information pertaining to taxes paid (net of refunds received) to be disaggregated for federal, state and foreign taxes and further disaggregated for specific jurisdictions to the extent the related amounts exceed a quantitative threshold. ASU 2023-09 will be effective for the Company in the annual periods beginning after December 15, 2025. Early adoption is permitted for annual financial statements that have not yet been issued or made available for issuance. The Company is currently assessing the impact adoption of ASU 2023-09 will have on its consolidated financial statements and related disclosures. In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses (“ASU 2024-03”). ASU 2024-03 will require disclosure of disaggregated information about certain income statement expense line items on an annual and interim basis, including purchases of inventory, employee compensation, depreciation, intangible asset amortization and depletion for each income statement line item that contains those expenses. ASU 2024-03 also will require certain amounts already disclosed under existing U.S. GAAP to also be disclosed as a separate category in disaggregated expense table(s), if those amounts are recognized in the relevant expense line item. The amendments in ASU 2024-03 will be effective for the Company in annual reporting periods beginning after December 15, 2026, and interim reporting periods within annual reporting periods beginning after December 15, 2027. The Company is currently assessing the impact adoption of ASU 2024-03 will have on its consolidated financial statements and related disclosures. In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements (“ASU 2025-11”) to provide clarifications intended to improve the consistency and usability of interim disclosure requirements. ASU 2025-11 includes a comprehensive listing of required interim disclosures and a new disclosure principle for reporting material events occurring after the most recent annual period. ASU 2025-11 is effective for interim periods within annual reporting periods beginning after December 15, 2027, and early adoption is permitted. The amendments in this update permit an entity to apply the new guidance using a prospective or retrospective approach. The Company is currently assessing the impact adoption of ASU 2025-11 will have on its consolidated financial statements and related disclosures.

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2026

The Company’s condensed consolidated financial statements include the accounts of its subsidiaries, Hemab ApS and Hemab Therapeutics, Inc., which was a wholly owned subsidiary of Hemab ApS until April 1, 2026. As a result of the corporate reorganization described in Note 1 “Description of Business and Liquidity—Corporate Reorganization”, Hemab ApS became a wholly owned subsidiary of Hemab Therapeutics Holdings, Inc. and, accordingly, the Company’s consolidated financial statements are those of Hemab Therapeutics Holdings, Inc. for the periods after the corporate reorganization and are those of Hemab ApS for historical periods before the corporate reorganization. Management has concluded the Company has a single reporting segment for purposes of reporting financial condition and results of operations. All intercompany transactions and balances have been eliminated in accordance with ASC 810,

Consolidation

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”).

Unaudited Interim Consolidated Financial Information

The accompanying unaudited condensed consolidated financial statements have been prepared on the same basis as the annual consolidated financial statements of Hemab ApS and reflect, in the opinion of management, all adjustments of a normal and recurring nature that are necessary for the fair statement of the Company’s financial position as of March 31, 2026 and its results of operations and cash flows for the three months ended March 31, 2026 and 2025. The results of operations for the three months ended March 31, 2026 are not necessarily indicative of the results to be expected for the year ending December 31, 2026, or for any other future annual or interim period. The condensed consolidated balance sheet as of December 31, 2025 included herein was derived from the audited financial statements of Hemab ApS as of that date. Certain information and footnote disclosures normally included in consolidated financial statements prepared in accordance with GAAP have been condensed or omitted from these unaudited condensed consolidated financial statements.

Foreign Currency

The financial statements are presented in U.S. dollars, the Company’s reporting currency. The functional currency of Hemab ApS and Hemab Therapeutics, Inc. is the U.S. dollar. Transaction gains and losses resulting from exchange rate changes on transactions denominated in currencies other than the U.S. dollar are recognized in other (expense) income, net in the consolidated statements of operations and comprehensive loss.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and in these accompanying notes. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors and assumptions that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, which include, but are not limited to, accrued research and development expenses, the fair value of the ordinary shares and warrants for equity-based compensation expense, and the valuation of the Company’s deferred tax assets. Changes in estimates are recorded in the period in which they become known.

Concentrations of Credit Risk

Financial instruments that potentially expose the Company to concentrations of credit risk primarily consist of cash, cash equivalents, and marketable securities. The Company’s investment portfolio is primarily comprised of short term debt securities issued by the U.S., Danish, and German governments. The Company places its cash in financial institutions that management believes to be of high credit quality and, consequently, the Company does not believe it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Bank accounts in the United States are insured by the Federal Deposit Insurance Corporation up to $250,000.

Deferred Offering Costs

Deferred offering costs consist of certain legal, professional, accounting and other third-party fees that are directly associated with the IPO. These direct costs are capitalized and recorded as other

non-current

assets on the condensed consolidated balance sheets. The deferred offering costs will be recorded against the IPO proceeds upon the consummation of the IPO, which was completed on May 4, 2026. As of March 31, 2026, the Company had $2.7 million of deferred offering costs.

Comprehensive Loss

Comprehensive loss includes net loss as well as other changes in stockholders’ deficit that result from transactions and events other than those with stockholders. The Company’s unrealized gains and losses on

available-for

sale-debt securities represent the only component of other comprehensive income (loss).

Recently Issued Accounting Standards

In December 2023, the FASB issued ASU

2023-09,

Income Taxes (Topic 740): Improvements to Income Tax Disclosures

(“ASU

2023-09”).

ASU

2023-09

will require disclosure of additional information in specified categories with respect to the reconciliation of the effective tax rate to the statutory rate (the rate reconciliation) for federal, state and foreign income taxes. ASU

2023-09

will also require information pertaining to taxes paid (net of refunds received) to be disaggregated for federal, state and foreign taxes and further disaggregated for specific jurisdictions to the extent the related amounts exceed a quantitative threshold. ASU

2023-09

will be effective for the Company in the annual periods beginning after December 15, 2025. Early adoption is permitted for annual financial statements that have not yet been issued or made available for issuance. The Company is currently assessing the impact adoption of ASU

2023-09

will have on its consolidated financial statements and related disclosures.

In November 2024, the FASB issued ASU

2024-03,

Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic

220-40):

Disaggregation of Income Statement Expenses

(“ASU

2024-03”).

ASU

2024-03

will require disclosure of disaggregated information about certain income statement expense line items on an annual and interim basis, including purchases of inventory, employee compensation, depreciation, intangible asset amortization and depletion for each income statement line item that contains those expenses. ASU

2024-03

also will require certain amounts already disclosed under existing U.S. GAAP to also be disclosed as a separate category in disaggregated expense table(s), if those amounts are recognized in the relevant expense line item. The amendments in ASU

2024-03

will be effective for the Company in annual reporting periods beginning after December 15, 2026, and interim reporting periods within annual reporting periods beginning after December 15, 2027. The Company is currently assessing the impact adoption of ASU

2024-03

will have on its consolidated financial statements and related disclosures.

In December 2025, the FASB issued ASU

2025-11,

Interim Reporting (Topic 270): Narrow-Scope Improvements

(“ASU

2025-11”)

to provide clarifications intended to improve the consistency and usability of interim disclosure requirements. ASU 2025-11 includes a comprehensive listing of required interim disclosures and a new disclosure principle for reporting material events occurring after the most recent annual period. ASU

2025-11

is effective for interim periods within annual reporting periods beginning after December 15, 2027, and early adoption is permitted. The amendments in this update permit an entity to apply the new guidance using a prospective or retrospective approach. The Company is currently assessing the impact adoption of ASU

2025-11

will have on its consolidated financial statements and related disclosures.