ClinicalTrials.gov posted results on 2026-08-17 for NCT03654833, the completed phase II Mesothelioma Stratified Therapy (MiST) trial. The British Lung Foundation-funded, University of Leicester study enrolled 186 participants with relapsed malignant mesothelioma and evaluated several treatment strategies, including atezolizumab plus bevacizumab.
Background
MiST was a multi-arm, stratified therapy trial for patients with relapsed mesothelioma. Its stated goal was to accelerate the evaluation of novel, personalised therapies as a basis for improving survival outcomes. The listed interventions were rucaparib; abemaciclib; pembrolizumab plus bemcentinib; atezolizumab plus bevacizumab; and dostarlimab plus niraparib.
Trial design
This was a phase II study listed as completed, with 186 participants. The condition recorded was malignant mesothelioma. Disease control rate was assessed at 12 and 24 weeks using modified RECIST 1.1. The results record lists five MiST groups, but the supplied measurements do not identify which group corresponds to each named intervention. The posted summary describes a stratified, multi-drug design rather than a single two-arm comparator trial.
Key results
At 12 weeks, the recorded disease-control participant counts were 15 participants in MiST-1, 14 participants in MiST-2, 12 participants in MiST-3, 13 participants in MiST-4, and 17 participants in MiST-5. At 24 weeks, the corresponding counts were 6 participants, 6 participants, 10 participants, 7 participants, and 8 participants.
The record also reported 24-week objective-response counts of 3 participants for MiST-1 and 4 participants for MiST-2. A proportion analysis reported 57.7% with a 95% confidence interval of 36.9% to 76.7%. Four additional proportion analyses reported 53.8% with a 90% confidence interval of 36.2% to 70.8%; 46.2% with a 90% confidence interval of 29.2% to 63.8%; 50.0% with a 90% confidence interval of 32.7% to 67.3%; and 65.4% with a 90% confidence interval of 47.4% to 80.6%. The listed 24-week disease-control analysis reported 23.1% with a 95% confidence interval of 9.0% to 43.7%. No p-values or adverse-event summary were provided.
What this means
The posted data document disease-control and objective-response measurements from a completed multi-arm study in relapsed mesothelioma. Because the supplied record does not link each result to a specific intervention, including atezolizumab plus bevacizumab, it does not establish the efficacy of that combination or provide a direct comparison with pembrolizumab or another treatment.
Source
This article is based on results posted by ClinicalTrials.gov on 2026-08-17 for NCT03654833. The source document is the ClinicalTrials.gov study record, available at clinicaltrials.gov.