Trial results for the Phase 2 study (NCT03007732) investigating pembrolizumab with or without SD-101 in hormone-naïve oligometastatic prostate cancer were posted on ClinicalTrials.gov on 2025-12-05. The study reported that 100% of participants in Cohort 2 achieved a prostate-specific antigen (PSA) change rate of < Nadir + 2 ng/mL at 15 months, regardless of SD-101 addition.
Background
This Phase 2 clinical trial investigated pembrolizumab in combination with stereotactic body radiation therapy (SBRT) and intermittent androgen deprivation therapy (iADT) for participants with newly diagnosed hormone-naïve oligometastatic prostate cancer. The study explored the addition of intratumoral SD-101 to this regimen.
Trial design
The study NCT03007732 was a Phase 2, non-comparative, open-label, multicenter clinical trial with an enrollment of 23 participants. The trial investigated treatment for newly diagnosed hormone-naïve oligometastatic prostate cancer. Interventions included pembrolizumab, stereotactic body radiation therapy (SBRT), and intermittent androgen deprivation therapy (iADT), with or without intratumoral SD-101. Other interventions listed were leuprolide acetate, abiraterone acetate, and prednisone. The study included two cohorts: Cohort 1 for prostate-only sites and Cohort 2 for prostate and oligometastatic sites.
Key results
For the outcome "Change Rate of Prostate-specific Antigen (PSA) < Nadir + 2 ng/mL From First Day of Treatment to 15 Months (Cohort 2)":
- In Cohort 2, Arm 1 (Prostate and Oligometastatic sites with ADT, SBRT, Pembrolizumab), the rate was 100% of participants.
- In Cohort 2, Arm 2 (Prostate and Oligometastatic sites with ADT, SBRT, Pembrolizumab, SD-101), the rate was 100% of participants.
Regarding "Number of Participants With Treatment-related Adverse Events":
- In Cohort 1, Arm 1 (Prostate Only Sites with ADT, SBRT, Pembrolizumab), the number of participants with treatment-related adverse events was reported as 1, 1, and 2 in separate measurements.
- In Cohort 1, Arm 2 (Prostate Only Sites with ADT, SBRT, Pembrolizumab, SD-101), the number of participants with treatment-related adverse events was reported as 0, 0, and 1 in separate measurements.
- In Cohort 2, Arm 1 (Prostate and Oligometastatic sites with ADT, SBRT, Pembrolizumab), the number of participants with treatment-related adverse events was reported as 0 and 0 in separate measurements.
- In Cohort 2, Arm 2 (Prostate and Oligometastatic sites with ADT, SBRT, Pembrolizumab, SD-101), the number of participants with treatment-related adverse events was reported as 0 and 0 in separate measurements.
What this means
The results from this Phase 2 trial suggest that the combination of pembrolizumab with SBRT and ADT, both with and without SD-101, can lead to a high rate of PSA response in participants with hormone-naïve oligometastatic prostate cancer. Specifically, the 100% rate of achieving PSA < Nadir + 2 ng/mL at 15 months in Cohort 2 indicates a strong initial response. Furthermore, the low numbers of reported treatment-related adverse events across all cohorts and arms suggest a favorable safety profile for these regimens in this small study population. These findings provide preliminary evidence for the potential efficacy and tolerability of these combination therapies, warranting further investigation in larger studies.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT03007732, titled "Pembrolizumab +/- SD-101 in Hormone-Naïve Oligometastatic Prostate Cancer With RT and iADT," were posted on 2025-12-05 on clinicaltrials.gov.