Atezolizumab Added to Bevacizumab Plus Platinum-Based Chemotherapy Did Not Improve PFS Among Patients With Platinum-Sensitive Ovarian Cancer

Primary efficacy and safety results from the ATALANTE/ENGOT-ov29 study demonstrated the addition of atezolizumab to bevacizumab and platinum-based chemotherapy did not statistically improve progression-free survival (PFS) among patients with previously treated, recurrent epithelial ovarian cancer. 

“In this setting, standard therapy includes a platinum-containing doublet (platinum with gemcitabine, paclitaxel, or pegylated liposomal doxorubicin) combined with bevacizumab,” stated Jean-Emmanule Kurtz, MD, PhD, Institut de Cancérologie Strasbourg, France, and coauthors. “As previous results hinted that immunotherapy might be more effective in less resistant recurrent [ovarian cancer], the ATALANTE/ENGOT-ov29 trial evaluated the anti–PD-L1 agent atezolizumab in platinum-sensitive [ovarian cancer].”

In this double-blind, placebo-controlled study, 614 patients with recurrent epithelial ovarian cancer previously treated with 1 to 2 lines of chemotherapy and a platinum-free interval (PFI) of >6 months were randomized on a 2-to-1 basis to receive 1200 mg of atezolizumab once every 3 weeks (n = 410) or placebo (n = 204). In both arms, treatment was followed by bevacizumab plus 6 cycles of chemotherapy doublet. Patients were stratified by PFI, PD-L1 status, and chemotherapy regimen. The coprimary end points were investigator-assessed PFS in both the intention-to-treat (ITT) and PD-L1-positive populations. The secondary end point was overall survival (OS). 

At the data cutoff date of October 15, 2021, the median duration of follow-up was 36.6 months. In the ITT population, median PFS was 13.5 months in the atezolizumab arm and 11.3 months in the placebo arm (hazard ratio [HR], 0.83; 95% CI, 0.69 to 0.99; P = .0410). In the PD-L1-positive population, median PFS was 15.2 months in the atezolizumab arm and 13.1 months in the placebo arm (HR, 0.86; 95% CI, 0.63 to 1.16; P = .30). Neither end point reached the threshold for statistical significance. OS data was immature, with a median OS of 35.5 months in the atezolizumab arm and 30.6 months in the placebo arm with a HR of 0.81. 

Global health quality of life did not differ between the 2 treatment arms; grade ≥3 adverse events occurred in 88% of patients in the atezolizumab arm and 87% of patients in the placebo arm. Grade ≥3 adverse events typical of immunotherapy were more common in patients treated with atezolizumab.

As concluded by Dr Kurtz and coauthors, “ATALANTE/ENGOT-ov29 did not meet its coprimary PFS objectives in the ITT or PD-L1–positive populations [however] OS follow-up continues.”

These results are “in line with multiple negative trials of immune checkpoint inhibition for patients with [ovarian cancer] treated in the front-line setting,” added associate editor of Journal of Clinical Oncology, Gini F. Fleming, MD, University of Chicago Medicine, Illinois. 

Source: 

Kurtz JE, Pujade-Lauraine E, Oaknin A, et al. Atezolizumab combined with bevacizumab and platinum-based therapy for platinum-sensitive ovarian cancer: Placebo-controlled randomized phase III ATALANTE/ENGOT-ov29 trial. J Clin Oncol. Published online: August 29, 2023. doi: 10.1200/JCO.23.00529