Nature of the Business and Basis of Presentation	6 Months Ended
Jun. 30, 2026
Accounting Policies [Abstract]
Nature of the Business and Basis of Presentation	1. Nature of the Business and Basis of Presentation Nature of Business Parabilis Medicines, Inc. (the “Company”) is a clinical-stage biopharmaceutical company developing medicines addressing some of the most consequential, yet historically undruggable, protein targets driving human disease. The Company leverages its platform to pioneer a therapeutic modality, Helicons, which are stabilized helical peptides engineered to bind and precisely modulate proteins. The Company was incorporated in Delaware on July 10, 2015. The Company is developing preclinical and clinical drug candidates, primarily operates in the United States of America, and, to date, has devoted substantially all its efforts to research and development and fundraising activities. Risk and Uncertainties The Company is subject to risks and uncertainties common to clinical-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, and ability to secure additional capital to fund operations. Product candidates resulting from the Company’s current discovery efforts will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts will require significant amounts of additional capital, adequate personnel, infrastructure, and extensive compliance reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. Reverse Stock Split On June 3, 2026, the Company effected a 1-for-1.5389 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratios of each series of the Company's convertible preferred stock and the IPO Discount Price (see Note 10, Simple Agreement for Future Equity) of the Company's simple agreement for future equity (“SAFE”). Accordingly, all share and per share amounts for all periods presented in the accompanying condensed consolidated financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect this reverse stock split and adjustments of the convertible preferred stock conversion ratios and the IPO Discount Price for the SAFE. Liquidity The Company’s condensed consolidated financial statements have been prepared on the basis of continuity of operations, the realization of assets and satisfaction of liabilities in the ordinary course of business. In June 2026, the Company closed its initial public offering (“IPO”) pursuant to which it issued and sold 38,525,000 shares of common stock, inclusive of 5,025,000 shares of common stock sold pursuant to the underwriters' full exercise of their option to purchase additional common stock, at a public offering price of $20.00 per share. In addition, the Company issued and sold 4,166,666 shares of common stock to Regeneron Pharmaceuticals, Inc. (“Regeneron”) in a concurrent private placement at a price per share of $18.00, or 90% of the public offering price. The aggregate net proceeds received by the Company from the IPO and concurrent private placement were $787.9 million, after deducting underwriting discounts and commissions and offering expenses of $57.6 million. Additionally, in June 2026, the Company received a non-refundable upfront payment in the amount of $50.0 million under its License and Collaboration Agreement (the “Regeneron Agreement”) with Regeneron. Prior to the IPO, the Company received aggregate gross proceeds of $811.8 million from sales of convertible preferred stock, $15.0 million from borrowings under a term loan, and $50.0 million of gross proceeds from the issuance of a SAFE. The Company has incurred net losses and negative operating cash flows since inception and has an accumulated deficit of $639.3 million at June 30, 2026. The Company expects that its cash, cash equivalents and marketable securities will be sufficient to fund its operations for at least twelve months from the date these condensed consolidated financial statements were issued. The Company will need additional financing to support its continuing operations and pursue its growth strategy. Until such time as the Company can generate significant revenue from product sales, if ever, the Company expects to finance its cash needs through a combination of equity offerings, debt or royalty financings, and collaborations. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into collaborations or other arrangements. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to raise additional funds through these sources or other sources of funding when needed, the Company could be forced to delay, reduce or eliminate its research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect its business prospects. Although management continues to pursue these plans, 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. Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, Parabilis Security Corporation and Parabilis Medicines (Shanghai) Ltd. Co. All intercompany accounts and transactions have been eliminated in consolidation. The Company’s unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) for interim reporting and as required by Regulation S-X, Rule 10-01. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). The condensed consolidated interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the Company’s financial position as of June 30, 2026, and the results of its operations for the three and six months ended June 30, 2026 and 2025, and cash flows for the six months ended June 30, 2026 and 2025. The condensed balance sheet as of December 31, 2025 was derived from audited annual financial statements but does not include all disclosures required by GAAP. The results of operations for the interim periods are not necessarily indicative of results to be expected for the year ending December 31, 2026, any other interim periods, or any future year or period.

Nature of the Business and Basis of Presentation

6 Months Ended

Jun. 30, 2026

Nature of the Business and Basis of Presentation

1. Nature of the Business and Basis of Presentation

Nature of Business

Parabilis Medicines, Inc. (the “Company”) is a clinical-stage biopharmaceutical company developing medicines addressing some of the most consequential, yet historically undruggable, protein targets driving human disease. The Company leverages its platform to pioneer a therapeutic modality, Helicons, which are stabilized helical peptides engineered to bind and precisely modulate proteins. The Company was incorporated in Delaware on July 10, 2015. The Company is developing preclinical and clinical drug candidates, primarily operates in the United States of America, and, to date, has devoted substantially all its efforts to research and development and fundraising activities.

Risk and Uncertainties

The Company is subject to risks and uncertainties common to clinical-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, and ability to secure additional capital to fund operations. Product candidates resulting from the Company’s current discovery efforts will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts will require significant amounts of additional capital, adequate personnel, infrastructure, and extensive compliance reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.

Reverse Stock Split

On June 3, 2026, the Company effected a 1-for-1.5389 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratios of each series of the Company's convertible preferred stock and the IPO Discount Price (see Note 10, Simple Agreement for Future Equity) of the Company's simple agreement for future equity (“SAFE”). Accordingly, all share and per share amounts for all periods presented in the accompanying condensed consolidated financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect this reverse stock split and adjustments of the convertible preferred stock conversion ratios and the IPO Discount Price for the SAFE.

Liquidity

The Company’s condensed consolidated financial statements have been prepared on the basis of continuity of operations, the realization of assets and satisfaction of liabilities in the ordinary course of business. In June 2026, the Company closed its initial public offering (“IPO”) pursuant to which it issued and sold 38,525,000 shares of common stock, inclusive of 5,025,000 shares of common stock sold pursuant to the underwriters' full exercise of their option to purchase additional common stock, at a public offering price of $20.00 per share. In addition, the Company issued and sold 4,166,666 shares of common stock to Regeneron Pharmaceuticals, Inc. (“Regeneron”) in a concurrent private placement at a price per share of $18.00, or 90% of the public offering price. The aggregate net proceeds received by the Company from the IPO and concurrent private placement were $787.9 million, after deducting underwriting discounts and commissions and offering expenses of $57.6 million. Additionally, in June 2026, the Company received a non-refundable upfront payment in the amount of $50.0 million under its License and Collaboration Agreement (the “Regeneron Agreement”) with Regeneron. Prior to the IPO, the Company received aggregate gross proceeds of $811.8 million from sales of convertible preferred stock, $15.0 million from borrowings under a term loan, and $50.0 million of gross proceeds from the issuance of a SAFE. The Company has incurred net losses and negative operating cash flows since inception and has an accumulated deficit of $639.3 million at June 30, 2026. The Company expects that its cash, cash equivalents and marketable securities will be sufficient to fund its operations for at least twelve months from the date these condensed consolidated financial statements were issued.

The Company will need additional financing to support its continuing operations and pursue its growth strategy. Until such time as the Company can generate significant revenue from product sales, if ever, the Company expects to finance its cash needs through a combination of equity offerings, debt or royalty financings, and collaborations. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into collaborations or other arrangements. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to raise additional funds through these sources or other sources of funding when needed, the Company could be forced to delay, reduce or eliminate its research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect its business prospects. Although management continues to pursue these plans, 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.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, Parabilis Security Corporation and Parabilis Medicines (Shanghai) Ltd. Co. All intercompany accounts and transactions have been eliminated in consolidation.

The Company’s unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) for interim reporting and as required by Regulation S-X, Rule 10-01. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”).

The condensed consolidated interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the Company’s financial position as of June 30, 2026, and the results of its operations for the three and six months ended June 30, 2026 and 2025, and cash flows for the six months ended June 30, 2026 and 2025. The condensed balance sheet as of December 31, 2025 was derived from audited annual financial statements but does not include all disclosures required by GAAP. The results of operations for the interim periods are not necessarily indicative of results to be expected for the year ending December 31, 2026, any other interim periods, or any future year or period.