ATALANTE/ENGOT-ov29: final overall survival analysis

Until now, clinical trials evaluating immunotherapy in the treatment of ovarian cancer have yielded poor results. To improve the efficacy of immunotherapy in this setting, several innovative strategies are being explored. One of these strategies consists of combining immune checkpoint inhibitors (ICIs) with an anti-VEGF agent. Theoretically, anti-angiogenic therapy could remodel the tumour microenvironment making the tumour more sensitive to ICI therapy. One of the studies evaluating this strategy consists of the phase III ATALANTE/ENGOT-ov29 study. In this video, Prof Dr Hannelore Denys (Ghent University Hospital, Ghent, Belgium) discusses the final overall survival (OS) data of this study presented at ESMO 2024.

In ATALANTE, 614 patients with relapsed non-mucinous epithelial ovarian cancer with a platinum-free interval of at least 6 months and who received ≤2 prior chemotherapy lines were randomly assigned (2:1) to receive carboplatin-based chemotherapy plus bevacizumab in combination with either atezolizumab, or placebo. Previous results showed that the trial failed to meet its primary endpoint of a longer PFS for the atezolizumab-containing treatment (15.2 vs. 13.1 months; HR[95%CI]: 0.88[0.65-1.18], p= 0.40). The OS data presented at ESMO revealed a median OS of 35.8 months with atezolizumab as compared to 30.6 months with placebo. At the 5-year landmark, the probability of being alive was reported at 27% with atezolizumab, which was 10% higher than the 17% 5-year OS rate in the control arm.

A further subgroup analysis of the data did not reveal a predictive role for PD-L1 expression. However, this analysis did suggest a more pronounced OS benefit with the atezolizumab-based regimen in patients who received only 1 prior treatment line (HR[95%CI]: 0.68[0.54-0.85]) and in patients with a late relapse (platinum-free interval >12 months).