Multinational phase 3 trial of addition of atezolizumab to first-line bevacizumab and chemotherapy for advanced pleural mesothelioma

The multinational phase 3 BEAT-meso trial evaluated the addition of atezolizumab to first-line bevacizumab plus carboplatin-pemetrexed chemotherapy for advanced pleural mesothelioma. The study randomized patients (65% ECOG performance status 1; 78% epithelioid histology) to atezolizumab plus bevacizumab plus chemotherapy (ABC; n=200) or BC (n=200). The median duration of follow-up was 35 months. The median overall survival was 20.5 months with ABC versus 18.1 months with BC (HR 0.84; p=0.14), whereas the median progression-free survival was 9.2 versus 7.6 months (HR 0.72; p=0.0021). Among patients with non-epithelioid histology the OS was longer with ABC than with BC (HR 0.51; 95% CI 0.32-0.80), which was not seen among patients with epithelioid histology (1.01; 0.77-1.32). Grade ≥ 3 treatment related adverse event were reported in 55% of patients with ABC and 47% of patients with BC; quality of life was maintained with ABC with no clinically meaningul differences from BC. The authors conclude that the significant PFS benefit with ABC over BC did not translate into a significant OS benefit, except among patients with non-epithelioid histology.