Transgene and BioInvent to Present Updated Data on Armed Oncolytic virus BT-001, at ESMO 2025

Poster presentation of updated data on BT-001

from the Phase I part of the ongoing Phase I/IIa study in solid tumors

Strasbourg, France, and Lund, Sweden, July 28, 2025, 8:30 a.m. CEST – 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, will jointly present a poster on updated data from the Phase I part of the Phase I/IIa study of BT-001 at the European Society for Medical Oncology (ESMO) Annual Meeting. ESMO will take place in Berlin, Germany, from October 17 to 21, 2025.

Poster details

Title: “Updated clinical results of BT-001, an oncolytic virus expressing an anti-CTLA4 mAb, administered in combination with pembrolizumab in patients with advanced solid tumors.”

Abstract number: 2828

Authors: C. Lebbe, R. Bahleda, E. Ezine, B. Baroudjian, M. Sakkal, E. Rowinski, A. Vinceneux, S. Champiat, K. Bidet Huang, N. Stojkowitz, H. Makhloufi, A. Sadoun, A. Ropenga, M. Semmrich, A. McAllister, M. Chisamore, P. Cassier

The abstract will be available on ESMO’s website on October 13, 2025, at 00:05 CEST.

BT-001 is an oncolytic virus generated using Transgene’s Invir.IO® platform and its patented large-capacity VVcopTK-RR- oncolytic virus, which has been engineered to encode both a Treg-depleting recombinant human anti-CTLA-4 antibody generated by BioInvent’s proprietary n-CoDeR®/F.I.R.S.T™ platforms, and the human GM-CSF cytokine. BT-001 is being co-developed as part of a 50/50 collaboration on oncolytic viruses between Transgene and BioInvent. In the Phase I part of this study, as monotherapy and in combination with MSD’s anti-PD-1 therapy KEYTRUDA® (pembrolizumab), BT-001 has been shown to be well tolerated. BT-001 also showed the first signs of efficacy with clinical response in two out of six refractory patients, thirteen patients evaluated in total, when given in combination with pembrolizumab, with shrinkage of injected and non-injected lesions. Treatment with BT-001 converted “cold” tumors into “hot” ones, and induced T-cell infiltration, as well as PD(L)-1 expression in the tumor microenvironment (See press release from September 14, 2024 ).

The ongoing Phase I/IIa study () is a multicenter, open label, dose-escalation study evaluating BT-001 as a single agent and in combination with MSD’s (Merck & Co., Inc., Rahway, NJ, USA) anti-PD-1 therapy KEYTRUDA® (pembrolizumab). The last patient in the Phase I part was enrolled in August 2024.

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

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Contacts

About Transgene

Transgene (Euronext: TNG) is a biotechnology company focused on designing and developing targeted immunotherapies for the treatment of cancer. The Company’s clinical-stage programs consist of a portfolio of viral vector-based immunotherapeutics. TG4050, the first individualized therapeutic vaccine based on the myvac® platform is the Company’s lead asset, with demonstrated proof of principle in patients in the adjuvant treatment of head and neck cancers. The portfolio also includes other viral-vector-based immunotherapies: TG4001 for the treatment of HPV-positive cancers, as well as BT-001 and TG6050, two oncolytic viruses based on the Invir.IO® viral backbone. The Company also conducts innovative discovery and preclinical work, aimed at developing novel viral vector-based modalities.

With Transgene’s myvac® platform, therapeutic vaccination enters the field of precision medicine with a novel immunotherapy that is fully tailored to each individual. The myvac® approach allows the generation of a virus-based immunotherapy that encodes patient-specific mutations identified and selected by Artificial Intelligence capabilities provided by its partner NEC.

With its proprietary platform Invir.IO®, Transgene is building on its viral vector engineering expertise to design a new generation of multifunctional oncolytic viruses.

Additional information about Transgene is available at:

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About BioInvent

BioInvent International AB (Nasdaq Stockholm: BINV) is a clinical-stage biotech company that discovers and develops novel and first-in-class immuno-modulatory antibodies for cancer therapy, with currently five drug candidates in six ongoing clinical programs in Phase 1/2 studies for the treatment of hematological cancer and solid tumors, respectively. The Company’s validated, proprietary F.I.R.S.T.™ technology platform identifies both targets and the antibodies that bind to them, generating many promising new drug candidates to fuel the Company’s own clinical development pipeline and providing licensing and partnering opportunities.

The Company generates revenues from research collaborations and license agreements with multiple top-tier pharmaceutical companies, as well as from producing antibodies for third parties in the Company’s fully integrated manufacturing unit. More information is available at

Disclaimer Transgene

This press release contains forward-looking statements, which are subject to numerous risks and uncertainties, which could cause actual results to differ materially from those anticipated. The occurrence of any of these risks could have a significant negative outcome for the Company’s activities, perspectives, financial situation, results, regulatory authorities’ agreement with development phases, and development. The Company’s ability to commercialize its products depends on but is not limited to the following factors: positive pre-clinical data may not be predictive of human clinical results, the success of clinical studies, the ability to obtain financing and/or partnerships for product manufacturing, development and commercialization, and marketing approval by government regulatory authorities. For a discussion of risks and uncertainties which could cause the Company’s actual results, financial condition, performance or achievements to differ from those contained in the forward-looking statements, please refer to the Risk Factors (“Facteurs de Risque”) section of the Universal Registration Document, available on the AMF website (-france.org) or on Transgene’s website (). Forward-looking statements speak only as of the date on which they are made, and Transgene undertakes no obligation to update these forward-looking statements, even if new information becomes available in the future.

Disclaimer BioInvent

The press release contains statements about the future, consisting of subjective assumptions and forecasts for future scenarios. Predictions for the future only apply as the date they are made and are, by their very nature, in the same way as research and development work in the biotech segment, associated with risk and uncertainty. With this in mind, the actual outcome may deviate significantly from the scenarios described in this press release.

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