1. Organization, Nature of Operations and Basis of Presentation

Description of Business

Theriva Biologics, Inc. (the “Company” or “Theriva Biologics”) is a diversified clinical-stage company developing therapeutics designed to treat cancer and related diseases in areas of high unmet need. As a result of the Company’s acquisition of Theriva Biologics, S.L. (“VCN”, formerly named VCN Biosciences, S.L.), in March 2022 described in more detail below (the “Acquisition”), the Company transitioned its strategic focus to oncology through the development of VCN’s new oncolytic adenovirus platform designed for intravenous and intravitreal delivery to trigger tumor cell death, to improve access of co-administered cancer therapies to the tumor, and to promote a robust and sustained anti-tumor response by the patient’s immune system. The Company’s lead product candidate, VCN-01 (zabilugene almadenorepvec), is a clinical stage oncolytic human adenovirus that is modified for tumor-selective replication and to express an enzyme, PH20 hyaluronidase. VCN-01 has been evaluated in a Phase 2b clinical study for the treatment of pancreatic cancer (“VIRAGE”), and a Phase 1 clinical study for the treatment of retinoblastoma, as well as various other Phase 1 clinical studies for the treatment of other solid tumors including head and neck squamous cell carcinoma.

Basis of Presentation

The accompanying condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial information. Accordingly, they do not include all the information and notes required by Accounting Principles Generally Accepted in the United States of America (“U.S. GAAP”) for complete financial statements. The accompanying condensed consolidated financial statements include all adjustments, comprised of normal recurring adjustments, considered necessary by management to fairly state the Company’s results of operations, financial position, and cash flows. The operating results for the interim periods are not necessarily indicative of results that may be expected for any other interim period or for the full year. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s 2025 Form 10-K.

The condensed consolidated financial statements are prepared in conformity with U.S. GAAP, which requires the use of estimates, judgments and assumptions that affect the amounts of assets and liabilities at the reporting date and the amounts of revenue and expenses in the periods presented. The Company believes that the accounting estimates employed are appropriate and the resulting balances are reasonable; however, due to the inherent uncertainties in making estimates, actual results may differ from the original estimates, requiring adjustments to these balances in future periods. As of March 31, 2026, the Company has one operating segment (which includes the legacy Company business and the VCN business) and therefore one reporting segment.