Trial results for pembrolizumab (Keytruda) in participants with relapsed or refractory primary mediastinal large B-cell lymphoma (rrPMBCL) were posted on ClinicalTrials.gov on 2025-04-06. The Phase 1 study (NCT04317066) reported an objective response rate (ORR) of 42.9% as assessed by independent central review, with no participants discontinuing treatment due to adverse events.
Background
Pembrolizumab is an immunotherapy drug. This study investigated its use in Japanese participants with relapsed or refractory primary mediastinal large B-cell lymphoma (rrPMBCL), a type of B-cell lymphoma.
Trial design
The study, identified as NCT04317066 (MK-3475-A33/KEYNOTE-A33), was a Phase 1 trial. It enrolled 7 Japanese participants with relapsed or refractory primary mediastinal large B-cell lymphoma (rrPMBCL). The study's purpose was to evaluate the objective response, safety, and tolerability of pembrolizumab in this population.
Key results
The trial reported the following key measurements for pembrolizumab in participants with rrPMBCL:
- The Objective Response Rate (ORR) as assessed by Independent Central Review was 42.9% (Percentage of Participants).
- The Objective Response Rate (ORR) as assessed by Investigator was 57.1% (Percentage of Participants).
- The Disease Control Rate (DCR) as assessed by Independent Central Review was 57.1% (Percentage of Participants).
- The Disease Control Rate (DCR) as assessed by Investigator was 71.4% (Percentage of Participants).
- Regarding safety, the number of participants who experienced at least one adverse event (AE) was 7 (Participants).
- The number of participants who discontinued study treatment due to an adverse event (AE) was 0 (Participants).
What this means
The results from this Phase 1 study suggest that pembrolizumab demonstrates an objective response rate in Japanese participants with relapsed or refractory primary mediastinal large B-cell lymphoma. The observed response rates, combined with the finding that no participants discontinued treatment due to adverse events, indicate a potential benefit and acceptable tolerability profile for pembrolizumab in this specific patient population. These findings warrant further investigation in larger studies.
Source
The information for these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT04317066, titled "A Study of Pembrolizumab (MK-3475) in Participants With Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) (MK-3475-A33/KEYNOTE-A33)," were posted on 2025-04-06 on clinicaltrials.gov.