Business Description

. Overview We are 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, as described in more detail below (the “Acquisition”), we transitioned our 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. Our 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. ​ Prior to the Acquisition, our focus was on developing therapeutics designed to treat gastrointestinal (GI) diseases which included our clinical development candidates: (1) SYN-004 (ribaxamase), which is designed to degrade certain commonly used intravenous (IV) beta-lactam antibiotics within the GI tract to prevent microbiome damage, thereby preventing overgrowth and infection by pathogenic organisms such as Clostridioides difficile infection (CDI) and vancomycin resistant Enterococci (VRE), and reducing the incidence and severity of acute graft-versus-host-disease (aGVHD) in allogeneic hematopoietic cell transplant (HCT) recipients, and (2) SYN-020, a recombinant oral formulation of the enzyme intestinal alkaline phosphatase (IAP) produced under current good manufacturing practices (“cGMP”) conditions and intended to treat both local GI and systemic diseases. In February 2026, we entered into a license agreement (the “Rasayana License Agreement”) with Rasayana Therapeutics, Inc. (“Rasayana”), pursuant to which we granted Rasayana an exclusive worldwide license with the right to grant sublicenses to research, develop, manufacture and commercialize any Product (as such term is defined in the Rasayana License Agreement), which includes SYN-020, comprising, containing, or covered by the Licensed IP (as such term is defined in the Rasayana License Agreement) and/or devised, developed, or produced using the Licensed IP. Pursuant to the terms of the Rasayana License Agreement, Rasayana will assume all responsibility and costs for the development and commercialization of the Products. We believe that this arrangement will provide us with potential to derive value from our SYN-020 asset, without the need for us to continue to invest additional working capital into the further development of the product candidate, thereby allowing us to focus our efforts and expenditures on the development of our oncology assets. Additionally, as part of our strategic transformation into an oncology focused company, we are exploring value creation options for our SYN-004 asset, including out-licensing or partnering. 6 Table of Contents Our Current Product Pipeline *Based on management’s current beliefs and expectations allo-HCT allogeneic hematopoietic cell transplant. HNSCC head and neck squamous cell carcinoma. IV intravenous. IVit intravitreal. For other abbreviations see the text. ¹Final Phase 1b/2a study cohort contingent on grant funding or partnership. ²Pursuant to the Rasayana License Agreement, commencing February 7, 2026, Rasayana is responsible for all development and commercialization efforts, including all costs related thereto, of SYN-020, and is obligated to use commercially reasonable efforts to meet certain specified development milestones, as more particularly set forth in the Rasayana License Agreement. Additional products with preclinical proof-of-concept include SYN-006 (carbapenemase) to prevent aGVHD, CDI, and microbiome damage in patients treated with carbapenem antibiotics and SYN-007 (ribaxamase) DR to prevent antibiotic associated diarrhea with oral β-lactam antibiotics.…