Trial results for the Phase 2 study (NCT03873818) investigating low-dose ipilimumab in combination with pembrolizumab (Keytruda) for patients with melanoma that has spread to the brain were posted on ClinicalTrials.gov on 2026-01-09. The study reported a Clinical Benefit Rate (CBR) of 68.4% in treatment-naïve patients, indicating a favorable response in this challenging population.
Background
Pembrolizumab (Keytruda) is an immunotherapy drug. This trial investigated its use in combination with low-dose ipilimumab for treating patients with melanoma that has spread to the brain. The study's brief summary indicates that immunotherapy with monoclonal antibodies like ipilimumab and pembrolizumab may help the body's immune system attack the cancer.
Trial design
The Phase 2 trial (NCT03873818), titled "Low Dose Ipilimumab With Pembrolizumab in Treating Patients With Melanoma That Has Spread to the Brain," enrolled 24 participants. The study focused on patients with Clinical Stage IV Cutaneous Melanoma AJCC v8, Metastatic Malignant Neoplasm in the Brain, and Metastatic Melanoma. Participants were divided into two cohorts: Cohort A for treatment-naïve patients and Cohort B for patients who had previously progressed on PD-1 inhibitors. The interventions included ipilimumab and pembrolizumab.
Key results
The trial reported several key measurements for the two cohorts. For Cohort A, consisting of treatment-naïve patients:
- The Clinical Benefit Rate (CBR) in PD-1 naïve patients was 68.4%.
- Median Overall Survival (OS) was 11.8 months.
- Median Progression-free Survival (PFS) was not available (NA).
For Cohort B, which included patients who had previously progressed on PD-1 inhibitors:
- The CBR for these patients was reported as 1 Participant.
- Median Overall Survival (OS) was 11.0 months.
- Median Progression-free Survival (PFS) was 1.4 months.
Regarding brain-specific safety and tolerability:
- In Cohort A, 0 Participants experienced one specific brain-related safety event, while 5 Participants experienced another.
- In Cohort B, 0 Participants experienced either of the assessed brain-related safety events.
What this means
The results suggest that the combination of low-dose ipilimumab with pembrolizumab may offer clinical benefit for patients with melanoma that has spread to the brain, particularly for those who are treatment-naïve, as evidenced by the 68.4% CBR in Cohort A. The observed median overall survival in both cohorts provides additional insight into the potential efficacy of this regimen. The brain-specific safety data indicates that the regimen was generally well-tolerated in the central nervous system for most participants.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT03873818, titled "Low Dose Ipilimumab With Pembrolizumab in Treating Patients With Melanoma That Has Spread to the Brain," were posted on 2026-01-09 on clinicaltrials.gov.