Trial results for atezolizumab in combination with bevacizumab and chemotherapy for malignant pleural mesothelioma were posted on ClinicalTrials.gov on 2026-05-14. The Phase 3 BEAT-meso study showed that the atezolizumab combination arm achieved a median overall survival of 20.5 months compared to 18.1 months for the control arm.
Background
The BEAT-meso trial investigated atezolizumab, a monoclonal antibody, in patients diagnosed with malignant pleural mesothelioma. This type of lung cancer is often advanced, and the trial aimed to assess the efficacy, safety, and tolerability of adding atezolizumab to existing treatment regimens.
Trial design
The Phase 3 BEAT-meso study (NCT03762018) enrolled 400 participants with advanced malignant pleural mesothelioma. The trial compared the efficacy and safety of atezolizumab plus bevacizumab in combination with standard chemotherapy (carboplatin and pemetrexed) against bevacizumab plus standard chemotherapy alone. The study was designed with a primary hypothesis to increase median overall survival from 17 months in the control arm to 24 months in the experimental arm, corresponding to a hazard ratio of 0.708.
Key results
Key results from the BEAT-meso trial include:
- Overall Survival (OS): The median OS was 20.5 months for the atezolizumab plus bevacizumab plus chemotherapy group, compared to 18.1 months for the bevacizumab plus chemotherapy group.
- Progression-free Survival (PFS): Median PFS was 9.2 months for the atezolizumab combination arm and 7.6 months for the control arm, according to mRECIST v1.1.
- Objective Response Rate (ORR): 110 participants in the atezolizumab combination arm achieved an objective response, compared to 98 participants in the control arm.
- Disease Control (DC) at 24 Weeks: 134 participants in the atezolizumab combination arm achieved disease control, versus 115 participants in the control arm.
- Time to Treatment Failure (TTF): Median TTF was 6.5 months for both the atezolizumab combination arm and the control arm.
- Duration of Response (DoR): Median DoR was 8.2 months for the atezolizumab combination arm, compared to 5.6 months for the control arm.
A Cox regression analysis for overall survival yielded a Hazard Ratio (HR) of 0.84 (95% Confidence Interval: 0.66 to 1.06) with a p-value of 0.14.
What this means
The BEAT-meso trial results indicate that adding atezolizumab to bevacizumab and standard chemotherapy for malignant pleural mesothelioma led to numerically longer median overall survival and progression-free survival compared to the control arm. Specifically, median OS was 2.4 months longer in the atezolizumab combination group. While these improvements are observed, the hazard ratio of 0.84 for overall survival, with a p-value of 0.14, suggests that the study did not meet its pre-specified statistical significance for the primary hypothesis (HR of 0.708 at a 1-sided significance level of 2.5%). However, the directional findings for OS, PFS, and DoR suggest potential clinical benefit that warrants further consideration.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for the study NCT03762018, titled "BEAT-meso: Bevacizumab and Atezolizumab in Malignant Pleural Mesothelioma", were posted on 2026-05-14 on clinicaltrials.gov.