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Transgene's Vaccine for HPV16-Related Cancers Shows Anti-Tumor Activity With Bavencio

NEW YORK – Transgene on Tuesday reported that the combination of its therapeutic vaccine TG4001 and the monoclonal antibody avelumab (EMD Serono/Pfizer's Bavencio) demonstrated activity in patients with previously treated, recurrent or metastatic human papillomavirus-related cancers.

The Phase Ib/II trial enrolled 34 patients with HPV16-positive anal, oropharyngeal, cervical, vulvar, or vaginal cancers, most of whom had received at least one line of previous treatment. All patients received TG4001 and avelumab, and eight experienced tumor shrinkage with the combo, resulting in an overall response rate of 23.5 percent. One patient had a complete response and seven had partial responses. These responses were observed across all primary tumor types and regardless of the number of prior lines of treatment.

Patients with HPV-related cancer whose tumors have metastasized in the liver usually have a poorer prognosis. As such, the trial explored the activity of the combination regimen in patients with and without liver metastases and showed that those in the latter group fared better. In the 23 patients without liver metastases, the response rate was 34.8 percent and median progression free survival was 5.6 months. In comparison, of the 11 patients with liver metastases, none responded to the treatment and the median progression free survival was 1.4 months.

The researchers evaluated 11 patients for T-cell responses after 43 days and found that seven had vaccine-induced reactive T-cells against E6 and E7, the antigens targeted by TG4001. Researchers also found increased immune cell infiltration in tumors, expression of immune-related genes, and higher PD-L1 protein expression across all patients.

Transgene conducted the Phase Ib/II trial in collaboration with Merck KGaA and Pfizer. The Phase II portion of the trial confirmed that TG4001 had a "favorable" safety profile, which had been previously explored in the Phase Ib part of the trial.

"Based on these promising findings, Transgene intends to continue the clinical development of TG4001 in a larger, controlled confirmatory study as we look to provide a better treatment option for this patient population," Maud Brandely, chief medical officer of Transgene, said in a statement.