Trial results for pembrolizumab (Keytruda) administered after radiation therapy in patients with pleural malignant mesothelioma were posted on ClinicalTrials.gov on 2025-11-13. The Phase 1 study reported 0 participants with safety/toxicity issues in both cohorts and a median overall survival of up to 16.3 months in one cohort.
Background
Pembrolizumab, also known as Keytruda, is an immunotherapy drug. This trial investigated its use after radiation therapy in patients with pleural malignant mesothelioma. The rationale for combining pembrolizumab with radiation therapy is to potentially enhance the immune system's attack on cancer cells and interfere with tumor growth and spread.
Trial design
The study, identified as NCT02959463, was a Phase 1 trial designed to evaluate the side effects and optimal administration of pembrolizumab following radiation therapy. It enrolled 24 participants diagnosed with pleural malignant mesothelioma. The trial investigated the intervention of pembrolizumab, with participants divided into two cohorts.
Key results
The trial reported key measurements for safety, overall survival, and progression-free survival. For the outcome of 'Safety/Toxicity':
- In Cohort 1, 0 participants experienced safety/toxicity issues.
- In Cohort 2, 0 participants experienced safety/toxicity issues.
For 'Overall Survival (OS)':
- The median OS for Cohort 1 was 12.2 months.
- The median OS for Cohort 2 was 16.3 months.
For 'Progression-Free Survival (PFS)':
- The mean PFS for Cohort 1 was 7.7 months.
- The mean PFS for Cohort 2 was 4 months.
What this means
The results from this Phase 1 trial suggest that pembrolizumab administered after radiation therapy for pleural malignant mesothelioma has a favorable safety profile, with no participants reporting safety/toxicity issues in either cohort. The observed median overall survival of up to 16.3 months and mean progression-free survival of up to 7.7 months provide early indications of potential clinical activity, warranting further investigation in larger trials for this challenging cancer.
Source
The information for these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT02959463, titled 'Pembrolizumab After Radiation Therapy in Treating Patients With Pleural Malignant Mesothelioma,' were posted on 2025-11-13 on clinicaltrials.gov.