Trial results for the Phase 2 study (NCT03401853) investigating pembrolizumab with rituximab or obinutuzumab in treating relapsed or refractory follicular lymphoma or diffuse large B-cell lymphoma were posted on ClinicalTrials.gov on 2025-04-18. The trial, which was terminated, showed an overall response rate of 29% in the arm combining pembrolizumab with rituximab for follicular lymphoma.
Background
Pembrolizumab is an immunotherapy designed to help the body's immune system attack cancer cells. Rituximab and obinutuzumab are monoclonal antibodies that bind to the CD20 protein, found on B cells and some types of cancer. This trial investigated these combinations in patients with relapsed or refractory follicular lymphoma or diffuse large B-cell lymphoma (DLBCL).
Trial design
The Phase 2 trial (NCT03401853) was designed to evaluate pembrolizumab in combination with other agents. It enrolled 18 participants with recurrent or refractory follicular lymphoma or diffuse large B-cell lymphoma. The study included three arms:
- Arm I: Pembrolizumab with rituximab for follicular lymphoma.
- Arm II: Pembrolizumab with rituximab for diffuse large B-cell lymphoma.
- Arm III: Pembrolizumab with obinutuzumab for follicular lymphoma.
The trial was ultimately terminated.
Key results
The trial evaluated overall response rates, incidence of serious or drug-related adverse events, progression-free survival (PFS), and overall survival (OS) across the study arms:
- Overall Response Rate (ORR):
- Arm I Follicular Lymphoma (Pembrolizumab, Rituximab): 29%.
- Arm II DLBCL (Pembrolizumab, Rituximab): 0%.
- Arm III Follicular Lymphoma (Pembrolizumab, Obinutuzumab): 0%.
- Incidence of Serious or Drug-related Adverse Events:
- Arm I Follicular Lymphoma (Pembrolizumab, Rituximab): 100%.
- Arm II DLBCL (Pembrolizumab, Rituximab): 63%.
- Arm III Follicular Lymphoma (Pembrolizumab, Obinutuzumab): 67%.
- Progression-free Survival (PFS) (median):
- Arm I Follicular Lymphoma (Pembrolizumab, Rituximab): 0.23 years.
- Arm II DLBCL (Pembrolizumab, Obinutuzumab): 0.21 years.
- Arm III Follicular Lymphoma (Pembrolizumab, Obinutuzumab): 0.50 years.
- Overall Survival (OS) (median):
- Arm I Follicular Lymphoma (Pembrolizumab, Rituximab): NA.
- Arm II DLBCL (Pembrolizumab, Obinutuzumab): 1.5 years.
- Arm III Follicular Lymphoma (Pembrolizumab, Obinutuzumab): NA.
What this means
The results from this Phase 2 trial suggest limited efficacy for pembrolizumab in combination with rituximab or obinutuzumab for relapsed or refractory follicular lymphoma and DLBCL. While Arm I showed an overall response rate of 29% in follicular lymphoma, the other arms reported 0% response rates. The high incidence of serious or drug-related adverse events across all arms, particularly 100% in Arm I, along with the trial's termination, indicates significant challenges in the safety and efficacy profile of these combinations in this patient population. The median progression-free survival and overall survival data also suggest modest benefits, with some arms showing "NA" for median OS.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT03401853, titled "Pembrolizumab With Rituximab or Obinutuzumab in Treating Patients With Relapsed or Refractory Follicular Lymphoma or Diffuse Large B Cell Lymphoma," were posted on 2025-04-18 on clinicaltrials.gov.