Combination Therapy Not Found to Improve Progression-Free Survival in Ovarian Cancer

The addition of atezolizumab (Tecentriq) to a backbone comprised of bevacizumab (Avastin) and chemotherapy failed to significantly improve progression-free survival (PFS) in patients with newly diagnosed stage III/IV ovarian cancer, according to results from the phase 3 IMagyn050/GOG 3015/ENGOT-OV39 trial presented during the virtual 2020 ESMO Congress. Results showed that the PFS in the intent-to-treat population (ITT; n = 1301) was 19.5 months with the atezolizumab combination versus 18.4 months with bevacizumab/chemotherapy (HR, 0.92; 95% CI, 0.79-1.07; P = .2785). In the PD-L1—positive population (n = 784), the median PFS with the atezolizumab regimen was 20.8 months versus 18.5 months with bevacizumab plus chemotherapy (HR, 0.80; 95% CI, 0.65-0.99; P = .0376).

However, results from exploratory PFS analyses demonstrated a trend favoring atezolizumab in a subgroup of patients with PD-L1 immune cells of 5% or greater, which could warrant further evaluation. Here, the median PFS with the atezolizumab regimen was not been reached versus 20.2 months in the bevacizumab/chemotherapy arm (HR, 0.64; 95% CI, 0.43-0.96).

“Despite notable successes with the incorporation of atezolizumab and bevacizumab into the treatment of other solid tumors, IMagyn050, the first such study done in ovarian cancer, did not meet its first primary end point for extending PFS in either the ITT or the fully powered PD-L1—positive population,” said Kathleen Moore, MD, lead author of the study, as well as the director of the Oklahoma TSET Phase I Program and associate professor in the Section of Gynecologic Oncology at Stephenson Cancer Center, said in a presentation during the meeting. “The signal of clinical benefit for atezolizumab in the immune cell PD-L1–high subgroup may warrant further evaluation.”

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