The Phase 3 BEAT-meso trial, evaluating atezolizumab in combination with bevacizumab and chemotherapy for malignant pleural mesothelioma, reached primary completion on 2023-09-01. Results showed the atezolizumab combination arm achieved a median overall survival of 20.5 months, compared to 18.1 months for the control arm, representing a 2.4-month numerical extension.
Background
The BEAT-meso trial investigated atezolizumab for patients diagnosed with malignant pleural mesothelioma. The study aimed to assess the efficacy, safety, and tolerability of atezolizumab plus bevacizumab in combination with standard chemotherapy.
Trial design
The Phase 3 BEAT-meso study (NCT03762018) enrolled 400 participants with malignant pleural mesothelioma. The trial compared the efficacy and safety of atezolizumab plus bevacizumab and standard chemotherapy (carboplatin and pemetrexed) against bevacizumab and standard chemotherapy alone. The primary objective was to assess Overall Survival (OS).
Key results
Key results from the BEAT-meso trial include:
- Overall Survival (OS): The median OS was 20.5 months in the atezolizumab combination arm compared to 18.1 months in the control arm.
- Progression-free Survival (PFS): Median PFS was 9.2 months for the atezolizumab combination arm versus 7.6 months for the control arm.
- 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 at 24 weeks, versus 115 participants in the control arm.
- Time to Treatment Failure (TTF): Median TTF was 6.5 months in both the atezolizumab combination arm and the control arm.
- Duration of Response (DoR): The median DoR was 8.2 months for the atezolizumab combination arm and 5.6 months for the control arm.
Statistical analysis for Overall Survival showed a Hazard Ratio (HR) of 0.84 (95% Confidence Interval: 0.66 to 1.06) with a p-value of 0.14. The study was designed to achieve 82.1% power at a 1-sided significance level of 2.5% for an HR of 0.708.
What this means
The BEAT-meso trial results indicate that adding atezolizumab to bevacizumab and chemotherapy numerically extended median overall survival by 2.4 months and median progression-free survival by 1.6 months in patients with malignant pleural mesothelioma. While these represent numerical improvements, the statistical analysis for overall survival, with a Hazard Ratio of 0.84 and a p-value of 0.14, did not meet the predefined statistical significance target (HR of 0.708 at a 1-sided significance level of 2.5%). This suggests that while there is a trend towards improved outcomes, the trial did not demonstrate a statistically significant benefit in overall survival under its specific design parameters. Clinicians will consider these results alongside other available treatment options for this challenging cancer.
Source
The information regarding the primary completion and results of the BEAT-meso trial 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 2023-09-01 on clinicaltrials.gov.