Transgene and BioInvent’s Oncolytic Virus BT-001 Shows Promising Antitumor Activity in Ongoing Phase I/IIa Trial in Solid Tumors that Failed Previous Treatments

Preliminary data presented at ESMO 2024 demonstrate that BT-001 induces tumor regression in patients who failed previous anti-PD(L)-1 treatment

In a patient with a heavily pretreated leiomyosarcoma, BT-001 was able to modulate the tumor microenvironment, turning a “cold” tumor to “hot”, enhancing the potential of T cell infiltration and a shift to PD(L)-1 positivity

Early signs of efficacy with clinical responses observed with BT-001 in combination with KEYTRUDA® (pembrolizumab), in 2 of 6 patients who failed previous treatment

Strasbourg, France, and Lund, Sweden, September 14, 2024, 9:05 a.m. CET – Transgene (Euronext Paris: TNG), a biotech company that designs and develops virus-based immunotherapies for the treatment of cancer, and BioInvent International AB (“BioInvent”) (Nasdaq Stockholm: BINV), a biotech company focused on the discovery and development of novel and first-in-class immune-modulatory antibodies for cancer immunotherapy, today announce new initial data from their ongoing Phase I/IIa study on the multifunctional oncolytic virus BT-001, demonstrating antitumor activity in patients who failed previous treatments.

The data presented today at the 2024 European Society for Medical Oncology (ESMO) Annual Meeting, show that BT-001 induced tumor regression in patients unresponsive to prior anti PD(L)-1 treatment, both as a monotherapy and in combination with MSD’s (Merck & Co., Inc., Rahway, NJ, USA) anti-PD-1 therapy KEYTRUDA® (pembrolizumab).

Preliminary translational data suggest that BT-001 replicates in the tumor where the payloads are expressed with undetectable systemic exposure. BT-001 alone or in combination with pembrolizumab was well tolerated and showed first signs of efficacy with clinical responses in 2 of 6 patients who failed previous treatments, when given in combination with pembrolizumab. BT-001 treatment turned “cold” tumors to “hot” inducing T cell infiltration, a higher M1/M2 ratio, and a shift to PD(L)-1 positivity in the tumor microenvironment.

Dr. Stéphane Champiat, Medical Oncologist, Head of the Inpatient Unit, Drug Development Department (DITEP) at Institut Gustave Roussy, commented: “The immunological data generated by BT-001 suggest that, as hoped, BT-001 is replicating in the tumor and its payload of transgenes is expressed with very limited exposure outside of the tumor thereby limiting systemic toxicity. I look forward to additional results from this ongoing study which will provide further evidence of the safety and clinical activity of BT-001 and its potential role as a new therapy for cancer patients with solid tumors.”

Transgene and BioInvent are co-developing BT-001, an oncolytic virus developed using Transgene’s Invir.IO® platform armed to express GM-CSF and BioInvent’s full-length anti-CTLA-4 monoclonal antibody, to elicit a strong and effective anti-tumoral response in solid tumors.

Dr. Alessandro Riva, Chairman and CEO of Transgene, said: “We are pleased to present the first promising clinical data on BT-001 at ESMO 2024, which confirm its mechanism of action as a single agent injected intratumorally and importantly demonstrate first signs of anti-tumor activity. Added to its good safety profile alone and in combination with pembrolizumab, BT-001 has the potential to shrink lesions and induce stable disease in refractory patients who may have few other treatment options. We will further explore the safety and efficacy of BT-001 in this development program with our partner BioInvent, and report additional data when it becomes available.”

Andres McAllister, MD, PhD, Chief Medical Officer at BioInvent International AB, concluded: “We are encouraged by the early clinical results presented at ESMO for BT-001, which encodes a potent Treg-depleting recombinant human anti-CTLA-4 antibody generated by our proprietary n-CoDeR® and F.I.R.S.T™ platforms. This clinical proof of concept confirms our ability to identify antibodies that bind to a selected target but exhibit a differentiated activity, allowing the development of promising new drug candidates such as BT-001.”    

The abstract and poster titled: “Initial clinical results of BT-001, an oncolytic virus expressing an anti-CTLA4 mAb, administered as single agent and in combination with pembrolizumab in patients with advanced solid tumors.”,  can be accessed on the ESMO and Transgene websites.

KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.