Theriva Biologics Provides Response to Unusual Market Action

ROCKVILLE, Md., Oct. 24, 2025 (GLOBE NEWSWIRE) -- Theriva™ Biologics (NYSE American: TOVX), (“Theriva” or the “Company”), a diversified clinical-stage company developing therapeutics designed to treat cancer and related diseases in areas of high unmet need, announced today that the Company had become aware of unusual trading activity in its common stock on the NYSE American (the “NYSE”) on October 24, 2025. The Company is issuing this press release pursuant to Section 401(d) of the NYSE Company Guide. The Company has made inquiries and does not believe corrective actions are appropriate. The Company is further announcing that there has been no material development in its business and affairs not previously disclosed or, to its knowledge, any other reason to account for the unusual market action. However, on October 13, 2025, the Company announced the presentation of expanded data from its VIRAGE trial investigating VCN-01 at a mini oral session at the European Society for Medical Oncology (ESMO 2025) Annual Congress.

Theriva™ Biologics (NYSE American: TOVX), is a diversified clinical-stage company developing therapeutics designed to treat cancer and related diseases in areas of high unmet need. The Company’s subsidiary Theriva Biologics, S.L., has been developing a new oncolytic adenovirus platform designed for intravenous (IV), intravitreal and antitumoral delivery to trigger tumor cell death, improve access of co-administered cancer therapies to the tumor, and promote a robust and sustained anti-tumor response by the patient’s immune system. The Company’s lead clinical-stage candidates are: (1) VCN-01 (zabilugene almadenorepvec), an oncolytic adenovirus designed to replicate selectively and aggressively within tumor cells, and to degrade the tumor stroma barrier that serves as a significant physical and immunosuppressive barrier to cancer treatment; (2) SYN-004 (ribaxamase) which is designed to degrade certain commonly used IV beta-lactam antibiotics within the gastrointestinal (GI) tract to prevent microbiome damage, thereby limiting overgrowth of pathogenic organisms such as VRE (vancomycin resistant Enterococci) and reducing the incidence and severity of acute graft-versus-host-disease (aGVHD) in allogeneic hematopoietic cell transplant (HCT) recipients; and (3) SYN-020, a recombinant oral formulation of the enzyme intestinal alkaline phosphatase (IAP) produced under cGMP conditions and intended to treat both local GI and systemic diseases. For more information, please visit Theriva Biologics’ website atwww.therivabio.com.