The ATALANTE trial evaluating the addition of atezolizumab to platinum-based chemotherapy plus bevacizumab for platinum-sensitive ovarian cancer failed to meet its coprimary progression-free survival (PFS) end points, according to data presented at the 2022 ESMO Congress.

These findings were presented by Prof Jean Emmanuel Kurtz, MD, Institut De Cancérologie, Strasbourg, France, lead author of the study.

“The ATALANTE trial is the first phase 3 trial to evaluate the addition of atezolizumab to standard therapy in patients with recurrent, platinum-sensitive ovarian cancer,” wrote Dr Kurtz and colleagues. Standard therapy for this patient population includes carboplatin plus pegylated liposomal doxorubicin or gemcitabine or paclitaxel with or without bevacizumab.

A total of 614 patients were randomized in a 2:1 ratio to atezolizumab (n = 410) or placebo (n = 204) with investigator’s choice of platinum-based chemotherapy regimen plus bevacizumab between October 2016 and September 2019. Patients were stratified by platinum-free survival, PD-L1 status, and type of chemotherapy.

The coprimary study end points were investigator-assessed PFS in the intent-to-treat (ITT) population and those with PD-L1-positive tumors.

The median follow-up was 36 months. In the ITT population, the median PFS was 13.5 months in the atezolizumab arm vs 11.2 months in the placebo arm (hazard ratio [HR], 0.83; 95% confidence interval [CI], 0.69 to 0.99; P = .041). In the PD-L1-positive population, the median PFS was 15.2 months with atezolizumab vs 13.1 months with placebo (HR, 0.86; 95% CI, 0.63 to 1.16; P = .30).

Median overall survival (OS), assessed at 333 of 491 planned events in the ITT population, was 35.4 months in the atezolizumab arm vs 30.6 months in the placebo arm (HR, 0.81; 95% CI, 0.65 to 1.01).

Grade ≥3 adverse events (AEs) occurred in 88% of patients who received atezolizumab vs 86% of patients who received placebo. Grade ≥3 immune AEs occurred in 13% vs 8% of patients, respectively. A total of 5 treatment-related deaths were reported: 3 in the atezolizumab arm and 2 in the placebo arm.

“The ATALANTE trial evaluating the addition of atezolizumab to standard therapy of [patients with recurrent, platinum-sensitive ovarian cancer] did not meet its PFS coprimary end points in the ITT and PD-L1-positive [populations],” concluded Dr Kurtz and colleagues, adding “Encouraging OS data warrant further analyses with longer follow-up.”

Source:

Kurtz JE, Pujade-Lauraine E, Oaknin A, et al. Phase III ATALANTE/ov29 trial: Atezolizumab (Atz) versus placebo with platinum-based chemotherapy (Cx) plus bevacizumab (bev) in patients (pts) with platinum-sensitive relapse (PSR) of epithelial ovarian cancer (OC). Presented at: ESMO Congress; September 9-13, 2022. Paris, France and virtual. Abstract LBA30.