David O’Malley, MD, director of the Division of Gynecologic Oncology at Ohio State and member of the Translational Therapeutics Program at the OSUCCC – James, presented the preliminary study results last September at the European Society for Medical Oncology (ESMO) Virtual Congress 2020. O’Malley was the lead presenter for both trials, which were sponsored by Agenus Inc.
Each study involved more than 150 patients with recurrent or metastatic cervical cancer from cancer treatment centers across the United States and Europe. All patients had platinum-based chemotherapy as a first-line therapy. The two independent but consecutive phase II trials tested a new immune-based agent called balstilimab given alone or in combination with a second monoclonal antibody drug called zalifrelimab.
Balstilimab is part of a class of drugs called checkpoint inhibitors. These drugs target the PD-1 protein within cancer cells and act as an “on” switch to help the immune system recognize and destroy cancer cells that would otherwise go undetected. Zalifrelimab delivers engineered molecules (monoclonal antibodies) that allow for improved immune response to attack cancer cells.
For the first study, 160 patients were treated with single-agent balstilimab, resulting in a 14% response rate in all treated patients and a 19% response rate in PD-L1-positive patients.
For the second study, 155 patients were treated with balstilimab given in combination with zalifrelimab, resulting in a 22% response rate in all patients and a 27% response rate in PD-L1-positive patients. “These studies represent the largest trials of immunooncology therapies in relapsed cervical cancer to date and show that balstilimab and zalifrelimab may present meaningful new therapies for patients with cervical cancer,” O’Malley says. “Advances in these agents offer hope for patients who have limited treatment options. This is especially important because this disease disproportionately affects younger women.”