Transgene’s therapeutic vaccine candidate TG4001 has flunked a phase 2 solid tumor trial. But, while the prospect failed to improve progression-free survival (PFS), the French biotech is continuing to analyze aspects of the data including a “positive efficacy trend” in a prespecified subgroup before deciding on its next steps.
The clinical trial assessed the effect of adding TG4001 to the checkpoint inhibitor Bavencio. TG4001 is a viral-based vaccine that expresses HPV16 E6/E7 proteins and IL-2. The vaccine is designed to teach the immune system to recognize and destroy cells that express E6 and E7 antigens, leading Transgene to test the candidate in recurrent or metastatic HPV16-positive cervical and anogenital cancers.
Adding TG4001 to Bavencio had no statistically significant effect on PFS in the trial, causing the midphase study to miss its primary endpoint. Transgene’s share price fell 13% to just above 1 euro in early trading in Paris on Monday.
Transgene CEO Alessandro Riva, M.D., said the failure was disappointing in a statement to disclose the result but also identified a potential silver lining. The team is “encouraged by the positive efficacy trend in favor of the combination regimen in cervical cancer patients,” Riva said, and will finish a full analysis of the data before deciding on the next steps.
Transgene said the cervical cancer signal requires further confirmation, including by looking at PD-L1 status in the population. PD-L1 status could affect the efficacy of Bavencio. People with cervical cancer accounted for around half of the participants in the trial.
Riva discussed the potential to partner the program on an earnings call in September but Transgene will only decide the next steps once it has completed its analysis of the data. If the biotech identifies a case for further development in cervical cancer, it, and any partner that signs up, will wade into a space that is being reshaped by new treatment options.
In September 2023, Riva told investors that Transgene was “observing a progressive slowdown in patient recruitment in the trial due to the recent availability of new treatments in first-line and second-line cervical cancer.” Seagen, now part of Pfizer, won accelerated FDA approval for Tivdak in cervical cancer in September 2021. That drug now has full approval, while Merck & Co.'s Keytruda won approval in the tumor type in 2021.
Transgene remains focused on its lead asset TG4050, an individualized cancer vaccine that is in a phase 1/2 trial in people with head and neck cancer. The company expects to share 24-month data on phase 1 patients in November.