Transgene Provides Business and Financial Update for Q1 2026

• Enrolment completed in Phase 2 part of head and neck cancer clinical trial (TG4050) – Topline data expected by the end of Q1 2028 as per plan
• Phase 1 data from TG4050 in head and neck cancer published on medRxiv
• License agreement signed with NEC Bio to advance clinical development of TG4050 in head and neck cancer
• Financial visibility until early 2028

Strasbourg, France, April 29, 2026, 5:45 p.m. CET – Transgene (Euronext Paris: TNG), a biotech company that designs and develops virus-based immunotherapies for the treatment of cancer, today provides a business update on its myvac® platform, and its individualized neoantigen therapeutic vaccine (INTV) TG4050, and upcoming plans, including its financial position as of March 31, 2026.

TG4050, Transgene’s first INTV from its myvac® platform continues to progress according to plan in the adjuvant treatment of head and neck cancer

TG4050 is designed to stimulate a strong and individualized immune response aimed at preventing relapse in HPV-negative head and neck cancer (HNSCC¹) patients following surgery and adjuvant (chemo)radiotherapy. It is currently under evaluation in a randomized multicenter Phase 1/2 clinical trial (NCT04183166).

As a monotherapy, TG4050 met all trial endpoints in the Phase 1 part of the trial and induced long-lasting immune responses to individualized vaccine neoantigens that were sustained for up to two years after treatment initiation. All patients treated were disease-free at 2 years, providing robust clinical proof of principle.

A comprehensive analysis of these positive clinical and translational data from the Phase 1 part of the randomized Phase 1/2 trial of TG4050 was published on the preprint platform medRxiv, in January 2026 (see press release). The data suggest that individualized treatment with TG4050 has the potential to prevent cancer relapses. The article is under review by a peer-reviewed journal. These data have also been presented orally at the World Vaccine Congress (WVC) (see press release).

• 3-year disease-free survival (DFS) follow-up of Phase 1 patients is expected in Q2/Q3 2026.

Transgene announced that the randomization of the Phase 2 part of the Phase 1/2 trial for adjuvant treatment of HNSCC has been completed (see press release).

• The primary endpoint of the trial is 2-year DFS. Transgene expects to communicate these top-line results by the end of Q1 2028.

Early April 2026, Transgene and NEC Bio signed a license agreement to advance the clinical development of TG4050 in head and neck cancer (see press release). Transgene secures access to NEC’s AI-based neoantigen prediction platform, as well as rights to enable TG4050’s further clinical development and to support commercialization and potential partnering of the program. Under this agreement, Transgene has paid a technology access fee of €2.5 million in Transgene shares as well as a first tranche of €0.5 million from a total payment of a total €2.5 million in cash that will be paid out in several instalments through early 2028. Additional development and milestone payments will be paid upon progress of the clinical development of TG4050 in head and neck cancer.

Expanding the value of the myvac® platform

Transgene’s INTV platform, myvac®, has the potential to generate INTVs that could be used to improve treatment across a range of solid tumors where in many cases a significant unmet medical need remains.

• In parallel with the ongoing Phase 1/2 trial in HNSCC, Transgene is progressing with start-up activities for a new Phase 1 trial in a second indication in an early treatment setting, with the aim of initiating later in 2026, as soon as all conditions are met.

To further enhance value and unlock the full potential of the myvac® platform, Transgene continues to invest in the optimization of the manufacturing of its INTV candidates, with the aim of reducing turnaround time, enabling scalability and increasing capacity.

Operating revenue and financial visibility

During the first quarter of 2026, operating revenue amounted to €1.4 million compared to €2.5 million for the same period in 2025. It mostly comprised the research tax credit of €1.1 million compared to €2.3 million for the same period in 2025. In Q1 2025, eligible activities against which research tax credit could be claimed comprised manufacturing for the patients in the Phase 2 part of the TG4050 trial in HNSCC; most of these manufacturing activities were completed in Q1 2026, explaining the decrease of the RTC.

As of March 31, 2026, Transgene had €103.8 million in cash, cash equivalents and other financial assets, compared to €111.9 million as of December 31, 2025.  Over the first quarter of 2026, Transgene’s net cash burn² was €8.1 million compared to €14.8 million for the same period in 2025.

Under current plans, the company has sufficient cash to ensure financial visibility until early 2028.

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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, demonstrated proof of principle in patients in the adjuvant treatment of head and neck cancers (HNSCC – Head and neck squamous cell carcinoma). The Company has other viral vector-based assets, including BT-001, an oncolytic virus based on the Invir.IO® viral backbone, which is in clinical development. The Company also conducts innovative discovery and preclinical work, aimed at developing novel immunotherapies.
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.
Additional information about Transgene is available at: www.transgene.com
Follow us on LinkedIn: @Transgene — Bluesky: @Transgene —  X: @TransgeneSA

About myvac®
myvac® is a viral vector (MVA – Modified Vaccinia Ankara) based, individualized immunotherapy platform that has been developed by Transgene to target solid tumors. myvac®-derived products are designed to stimulate the patient’s immune system to recognize and destroy tumors using their own cancer specific genetic mutations. Transgene has set up an innovative network that combines bioengineering, digital transformation, established vectorization know-how and unique manufacturing capabilities. Transgene has been awarded “Investment for the Future” funding from Bpifrance for the development of its platform myvac®. TG4050 is the first myvac®-derived product being evaluated in clinical trials. Click here to watch a short video on myvac®.

About TG4050
TG4050 is an individualized immunotherapy being developed for solid tumors that is based on Transgene’s myvac® technology and powered by NEC’s longstanding artificial intelligence (AI) and machine learning (ML) expertise. This virus-based Individualized Neoantigen Therapeutic Vaccine (INTV) encodes neoantigens (patient-specific mutations) identified and selected by NEC’s Neoantigen Prediction System. The prediction system is based on more than two decades of expertise in AI and has been trained on proprietary data allowing it to accurately prioritize and select the most immunogenic sequences.
TG4050 is designed to stimulate the immune system of patients to induce a T-cell response that is able to recognize and destroy tumor cells based on their own neoantigens. This individualized immunotherapy is developed and produced for each patient.

About the Phase 1/2 Clinical Trial
TG4050 is being evaluated in a Phase 1/2 clinical trial for patients with HPV-negative head and neck cancers (NCT04183166). An individualized treatment is created for each patient after they complete surgery and while they receive adjuvant therapy. Half of the participants received their vaccine immediately after completing adjuvant treatment. The other half were given TG4050 at the time of recurrence of the disease as an additional treatment to the standard of care (SoC). This randomized study is evaluating the treatment benefits of TG4050 in patients who are at risk of relapse. The first efficacy data (2-year disease-free survival – DFS) will become available at the latest by the end of Q1 2028.

Disclaimer
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 (http://www.amf-france.org) or on Transgene’s website (www.transgene.com). 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.

¹ Head and neck squamous cell carcinoma – HNSCC

² Cash burn corresponds to the sum of net cash flows from operating, investing and financing activities, excluding proceeds from share issuances and excluding current account advance/other financial asset disposals related to the parent company. It does not include the effects of exchange rate fluctuations

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