NEW YORK – Transgene said on Wednesday it is expanding the Phase Ib/II trial of its therapeutic vaccine, TG4001, plus avelumab (Pfizer/Merck KGaA's Bavencio) in patients with advanced human papillomavirus (HPV)16-positive anogenital cancer without liver metastases.
The trial was changed to include a randomized comparison of TG4001 plus the PD-L1-targeting monoclonal antibody avelumab versus avelumab monotherapy. Transgene's amended protocol has been cleared in the US, and the firm has initiated the process to do the same in Europe. Enrollment will begin in Q2 of 2021, and by the final analysis, the study could involve as many as 136 patients with recurrent or metastatic, HPV16-positive anogenital cancer who don't have liver metastases.
The trial's primary endpoint is progression-free survival and secondary endpoints include objective response rate, disease control rate, and overall survival. Transgene expects to report interim data from the study by the end of 2022.
According to Maud Brandely, chief medical officer of France-based Transgene, the company hopes to discuss data from this study with regulators and carve out a registration path for TG4001 — a vaccine designed to help the immune system recognize cancer cells with HPV16 E6 and E7 antigens and charge up the "infection-clearing activity" of the immune system via interleukin 2.
In the initial Phase Ib/II trial of TG4001 plus avelumab, the response rate among HPV16-positive anogenital cancer patients without liver metastases was 34.8 percent and the median progression-free survival was 5.6 months. Among all patients, including those with liver metastases who usually have a poorer prognosis, 23.5 percent responded to the combination.
"The results from the initial Phase Ib/II study demonstrated the potential of the combination of TG4001 with an immune checkpoint inhibitor in this advanced disease setting," Brandely said in a statement. "The observed median progression-free survival shows that this combination can induce a sustained and durable benefit, which may be based on the induction of a specific immune response."