Clinical and immunologic impact of short-course enzalutamide alone and with immunotherapy in non-metastatic castration sensitive prostate cancer

Ravi A. Madan*, Fatima Karzai, Renee N. Donahue, Munjid Al-Harthy, Marijo Bilusic, Inger I. Rosner, Harpreet Singh, Philip M. Arlen, Marc R. Theoret, Jennifer L. Marté, Lisa Cordes, Anna Couvillon, Amy Hankin, Moniquea Williams, Helen Owens, Sarah E. Lochrin, Cindy H. Chau, Seth Steinberg, William Douglas Figg, William DahutJeffrey Schlom, James L. Gulley

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Background The standard treatment for non-metastatic castration sensitive prostate cancer (nmCSPC) is androgen deprivation therapy (ADT) or surveillance. This study evaluated the potential synergy of immunotherapy and enzalutamide (without ADT) in nmCSPC. In addition, the immunologic impact of enzalutamide was also evaluated in men with normal testosterone. Methods Patients with rising prostate-specific antigen (PSA) after definitive therapy, normal testosterone and no radiographic metastasis were randomized to enzalutamide for 3 months with/without PROSTVAC for 6 months. Thereafter, patients could be retreated with another 3 month course of enzalutamide when PSA returned to baseline. Immune profiles were evaluated in these patients. Results Thirty-eight patients were randomized with a median PSA=4.38 ng/dL and PSA doubling time=4.1 months. No difference was observed between the two groups for PSA growth kinetics, but PSA responses to enzalutamide were noteworthy regardless of PROSTVAC. The median PSA decline after short-course enzalutamide without ADT/testosterone lowering therapy was 99% in both courses. The median time to PSA recovery to baseline after each 84-day course of enzalutamide was also noteworthy because of the duration of response after enzalutamide was discontinued. After the first and second 3 month cycle of enzalutamide, PSA recovery to baseline took a median 224 (range 84-1246) and 189 days (78-400), respectively. The most common adverse events related to the enzalutamide were grade 1 fatigue (71%) and grade 1 breast pain/nipple tenderness (81%). The only grade 3 toxicity was aspartate aminotransferase (AST)/alanine aminotransferase (ALT) elevation in two patients. Enzalutamide was independently associated with immune changes, increasing natural killer cells, naïve-T cells, and decreasing myeloid-derived suppressor cells. Conclusions Three months of enzalutamide without ADT induced substantial PSA control beyond the treatment period and was repeatable, perhaps representing an alternative to intermittent ADT in nmCSPC. In addition, enzalutamide was associated with immune changes that could be relevant as future immune combinations are developed. Trail registration number (NCT01875250).

Original languageEnglish
Article number2020001556
JournalJournal for immunotherapy of cancer
Issue number3
StatePublished - 4 Mar 2021
Externally publishedYes


  • immunotherapy
  • killer cells
  • myeloid-derived suppressor cells
  • natural
  • prostatic neoplasms


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