Trial results for the Phase 1/2a study (NCT04260529) investigating CyPep-1 alone and in combination with pembrolizumab for advanced solid tumor malignancy were posted on ClinicalTrials.gov on 2026-01-29. The study reported adverse events across various cohorts and arms, with up to 262 events observed in one arm.
Background
The trial investigated CyPep-1 as a monotherapy and in combination with the anti-programmed cell death protein 1 (anti-PD-1) antibody pembrolizumab. The study focused on patients with advanced solid tumor malignancy.
Trial design
The Phase 1/2a trial (NCT04260529) was designed to assess the safety, tolerability, pharmacokinetics, and pharmacodynamics of CyPep-1 when administered directly into malignant tumors, both as a monotherapy and in combination with pembrolizumab. The study enrolled 60 participants with advanced solid tumor malignancy. Additionally, the trial aimed to monitor anti-tumor effects on both injected lesions and distant non-injected deposits.
Key results
The trial reported the type and number of adverse events (AEs) across different cohorts and arms:
- In Phase I Cohort 1, 24 adverse events were reported.
- In Phase I Cohort 2, 37 adverse events were reported.
- In Phase I Cohort 3, 62 adverse events were reported.
- In Phase IIa Arm A, 143 adverse events were reported.
- In Phase IIa Arm B, 262 adverse events were reported.
- In Phase IIa Arm C Cohort 4, 91 adverse events were reported.
- In Phase IIa Arm C Cohort 5, 91 adverse events were reported.
- In Phase IIa Arm D, 4 adverse events were reported.
Additional adverse event data was also reported for various cohorts:
- In Phase I Cohort 1, 1 adverse event was reported.
- In Phase I Cohort 2, 0 adverse events were reported.
- In Phase I Cohort 3, 0 adverse events were reported.
- In Phase IIa Arm A, 3 adverse events were reported.
What this means
The posted results provide initial safety and tolerability data for CyPep-1, both as a monotherapy and in combination with pembrolizumab, in patients with advanced solid tumor malignancy. The varying numbers of adverse events across the different cohorts and arms will inform further development regarding the safety profile of these interventions. As this was a Phase 1/2a trial, the primary focus was on safety and tolerability, and these results contribute to understanding the initial safety landscape of the investigational treatments.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT04260529, titled "CyPep-1 Injections in Cancer Inducing Lymphocyte Infiltrate Accumulations," were posted on 2026-01-29 on clinicaltrials.gov.