Vaccine Trials Ongoing in Locally Advanced Oligometastatic Prostate Cancer

CancerNetwork® spoke with Ketan K. Badani, MD, vice chairman of Urology and Robotics and director of the Comprehensive Kidney Cancer Center and Reconstructive Urology at Mount Sinai Health System, about the phase 1 poly-ICLC trial (NCT03262103), which tested the safety of sequential intratumoral plus systemic intramuscular injection of poly-ICLC. Safety results were published in Cancer Research and subsequently presented at the International Prostate Symposium and World Congress of Urologic Oncology in December 2024.

Badani expressed that there are multiple ongoing trials assessing personalized vaccine regimens, emphasizing that the vaccines for prostate cancer may serve as a delivery mechanism to prostate cancer cells vis different biomarkers. He the introduced the ploy-ICLC trial, led by his chair, Ash Tewari, MBBS, MCh, FRCS.

He then explained that in the trial, prostate cancer is biopsied, and a vaccine is developed based on the cells. The vaccine is then injected into patients to potentially inhibit metastases to enable localized treatment with curative intent. Badani further expressed that extrapolation to kidney is more complicated, with no way to create a vaccine in that indication similar to prostate cancer. He then stated that there are active trials assessing vaccines for locally advanced oligometastatic prostate cancer.

Treatment with poly-ICLC was well tolerated, with safety data from the open-label dose-escalating phase 1 study revealing that among evaluable patients (n = 12), there were no dose-limiting toxicities (DLTs) or treatment-emergent adverse event (TEAE) withdrawals observed during treatment. Furthermore, 8 of 10 patients (80%) had prostate-specific antigen (PSA) levels of less than 0.1 ng/ml at 1 year of follow-up.

Additionally, 8 of 12 patients (66.7%) had a lower Gleason score following radical prostatectomy, including 70% of patients with biopsy Gleason of 8 to 10. Efficacy analysis revealed that treatment with poly-ICLC increased systemic immune responses, and genes upregulated by the agent were associated with a good prognosis.

Transcript:

For locally advanced metastatic prostate cancer, there are definitely many [ongoing] trials assessing personalized vaccines and personalized treatment regimens. The vaccine concept for prostate cancer is important because you can actually develop a delivery mechanism to prostate cancer cells via different markers, like PSMA. We have a big, funded trial led by my chair, Ash Tewari, MBBS, MCh, FRCS––[the] poly-ICLC trial.

[We] biopsy the prostate cancer, the lab will develop the vaccine based on those cells, and then [we] inject it back into the patient in hopes of reducing and eliminating the metastatic part of the disease. Then, we can locally treat the prostate and cure the patient. This is exciting for prostate cancer. Its extrapolation to kidney is a bit more complicated. We cannot create a vaccine the same way one can for prostate [cancer] right now. It is an exciting point. We have active [vaccine] trials for locally advanced oligometastatic prostate cancer.

Reference

Nair SS, Chakravarty D, Balan S, et al. Abstract CT023: Prostate cancer in situ autovaccination with the intratumoral viral mimic poly-ICLC: making a cold tumor hot. Cancer Res. 2024;84(suppl 7):CT023. doi:10.1158/1538-7445.AM2024-CT023