Trial results for a Phase 1/2 study investigating PDS0101 alone or in combination with pembrolizumab for locally advanced human papillomavirus-associated oropharynx cancer were posted on ClinicalTrials.gov on 2026-04-14. The combination arm demonstrated a response rate of 0.2 (20%) in participants.
Background
Pembrolizumab is an immunotherapy agent, a monoclonal antibody designed to help the body's immune system attack cancer cells. PDS0101 is a vaccine composed of specific peptides, intended to stimulate an immune response against tumor cells. This trial focused on locally advanced human papillomavirus-associated oropharynx cancer, a condition where cancer has spread to nearby tissue or lymph nodes.
Trial design
This Phase 1/2 trial (NCT05232851) enrolled 20 participants, investigating treatments for various stages of human papillomavirus-associated oropharyngeal carcinoma, including locally advanced forms. The study evaluated PDS0101 alone (Arm A) and in combination with pembrolizumab (Arm B).
Key results
Key measurements from the trial included:
- For the "Proportion of Pathologic and Human Papillomavirus Cell-free Tumor Deoxyribonucleic Acid (ctHPVDNA) Response":
- Arm A (PDS0101): 0.5 proportion of participants
- Arm B (PDS0101, Pembrolizumab): 0 proportion of participants
- For "Response Rate":
- Arm A (PDS0101): 0 proportion of participants
- Arm B (PDS0101, Pembrolizumab): 0.2 proportion of participants
- For "Incidence of Adverse Events (AEs)":
- Arm A (PDS0101): 1 participant
- Arm B (PDS0101, Pembrolizumab): 2 participants
What this means
The results from this early-phase trial provide initial insights into the activity of PDS0101 alone and in combination with pembrolizumab for locally advanced human papillomavirus-associated oropharynx cancer. While the "Proportion of Pathologic and Human Papillomavirus Cell-free Tumor Deoxyribonucleic Acid (ctHPVDNA) Response" was observed in 0.5 of participants receiving PDS0101 alone, it was 0 in the combination arm. Conversely, the "Response Rate" was 0.2 in the combination arm compared to 0 for PDS0101 alone. The incidence of adverse events was low, with 1 participant in Arm A and 2 participants in Arm B experiencing events. Given the small enrollment of 20 participants and the Phase 1/2 nature of the study, these findings are preliminary and warrant further investigation in larger trials to clarify the efficacy and safety profiles of these treatment strategies.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT05232851, titled "A Vaccine (PDS0101) Alone or in Combination With Pembrolizumab for the Treatment of Locally Advanced Human Papillomavirus-Associated Orophar," were posted on 2026-04-14 on clinicaltrials.gov.