Before 2018, there was no standard of care for non-metastatic (M0) castration resistant prostate cancer nmCRPC. Androgen receptor antagonists (ARAs) were commonly used sequentially nmCRPC.
This was a multicenter, randomized clinical trial comparing the ARA flutamide+/-PROSTVAC, a pox viral vaccine targeting PSA that includes T-cell co-stimulatory molecules.
Eligible men had negative CT and Tc99 bone scans, and rising PSA on ADT. Previous treatment with ARA was a stratification factor. Patients were also evaluated for antigen-specific immune responses using intracellular cytokine staining.
Thirty-three patients randomized to flutamide and 31 to flutamide+vaccine. The median age was 71.8 and 69.8 years, respectively. The median time to treatment failure after a median potential follow-up of 46.7 months was, 4.5 months (range 2-70) for flutamide alone vs. 6.9 months (2.5-40; P = .38) with flutamide+vaccine. Seven patients in each arm had a >50% PSA response. Antigen-specific responses were similar in both arms (58% of patients in flutamide alone and 56% in flutamide+vaccine). The treatments were well tolerated. The most common side effect > grade 2 was injection site reaction seen in 29/31 vaccine patients which were self-limiting.
The combination of flutamide+PROSTVAC did not improve outcomes in men with nmCRPC compared with flutamide alone. (ClinicalTrials.gov Identifier: NCT00450463).
The oncologist. 2023 May 03 [Epub ahead of print]
Ravi A Madan, Marijo Bilusic, Mark N Stein, Renee N Donahue, Philip M Arlen, Fatima Karzai, Elizabeth Plimack, Yu-Ning Wong, Daniel M Geynisman, Matthew Zibelman, Tina Mayer, Julius Strauss, Gang Chen, Myrna Rauckhorst, Sheri McMahon, Anna Couvillon, Seth Steinberg, William D Figg, William L Dahut, Jeffrey Schlom, James L Gulley
National Cancer Institute, Bethesda, MD, USA., Division of Hematology/Oncology, Columbia University Medical Center, New York, NY, USA., Department of Hematology/Oncology, Fox Chase Cancer Center-Temple University Health System, Philadelphia, PA, USA., Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.