Trial results for the Phase 1 study investigating pembrolizumab (Keytruda) in combination with multiple antigen specific endogenously derived T cells (MASE-T) for metastatic melanoma were posted on ClinicalTrials.gov on 2025-07-25. The study was TERMINATED, with results indicating tolerability in 6 participants in Part A and 3 participants achieving best overall response in Part A.
Background
Pembrolizumab (Keytruda) is a well-established checkpoint inhibitor. The trial aimed to explore strategies to overcome resistance to existing therapies in malignant melanoma, specifically through adoptive cell therapy (ACT) using multiple antigen specific endogenously derived T cells (MASE-T), given that a subset of patients do not respond to current checkpoint inhibitor therapies.
Trial design
The ImmPACT Expanded Multiple Antigen Specific Endogenously Derived T Cells (MASE-T) to Patients With Metastatic Melanoma study (NCT04904185) was a Phase 1 trial. It was designed to investigate the combination of pembrolizumab with multiple antigen specific endogenously derived T cells, preceded by lymphodepleting chemotherapy with cyclophosphamide and fludarabine phosphate, in patients with Malignant Melanoma. The trial enrolled 8 participants and was ultimately TERMINATED.
Key results
The trial reported several key measurements from the study's Part A and Part B cohorts:
- For "Tolerability of the Treatment," 6 participants in Part A were reported, while 0 participants in Part B were reported.
- The "Number of Patients Excluded Due to Feasibility Issues" in Part A was 1 participant.
- The "Number of Patients Excluded Due to Safety Issues" in Part A was 0 participants.
- The "Best Overall Response (BOR)" in Part A was observed in 3 participants.
What this means
The termination of this Phase 1 trial suggests that the study did not proceed as initially planned. While tolerability was observed in 6 participants in Part A, and 3 participants showed a best overall response, the overall status of 'TERMINATED' indicates that further investigation into this specific combination therapy for metastatic melanoma was halted. This could be due to various factors, including feasibility challenges, safety concerns, or lack of sufficient efficacy signals to warrant continuation, though specific reasons for termination are not detailed in the results.
Source
The information for this article was sourced from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT04904185, titled 'ImmPACT Expanded Multiple Antigen Specific Endogenously Derived T Cells (MASE-T) to Patients With Metastatic Melanoma,' were posted on 2025-07-25 on clinicaltrials.gov.