Intense androgen deprivation therapy (ADT) for high-risk localized prostate cancer (PCa) prior to radical prostatectomy results in favorable pathologic responses in a subset of patients, investigators reported at the American Society of Clinical Oncology 2020 Virtual Scientific Program.

In the first part of a 2-part study that enrolled 119 men, intense neoadjuvant hormone therapy resulted in a 21% rate of pathologic complete response (pCR, no tumor) or minimum residual disease (MRD, tumor size 5 mm or less), Rana R. McKay, MD, of the University of California San Diego, and colleagues reported.

Study participants had a median age of 61 years. Of the 119 men, 111 (94%) had high-risk disease based on National Comprehensive Cancer Network criteria, including 73 patients (62%) with T3 disease, 84 (71%) with Gleason 8 to 10 tumors, and 28 (24%) with PSA levels above 20 ng/mL.

The study randomly assigned patients to receive a regimen that included abiraterone plus prednisone in addition to apalutamide and leuprolide (APAL) or abiraterone plus prednisone plus leuprolide (APL) for 6 cycles (28 days per cycle). A total of 114 patients (97%) completed 6 therapy cycles followed by radical prostatectomy. All radical prostatectomy specimens underwent central pathologic review. The combined pCR or MRD rates did not differ between study arms.


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“Our hypothesis was that more intense hormone therapy would result in improved pathologic responses,” Dr McKay told Renal & Urology News. “While we did not observe differences between the study arms, we demonstrate that a subset of patients with intense ADT have improved pathologic responses.” 
The second part of the study will examine the effect of an additional 12 months of APAL post-RP on biochemical recurrence.

The new findings raise the question of whether therapy intensification or de-escalation can be implemented if improvements in upfront molecular profiling, advanced imaging, and repeat tissue sampling can reliably show tumor eradication. “Our study was not designed to answer this question,” Dr McKay said, “but rationally designed biomarker- and imaging-driven trials need to validate the safety and efficacy of this approach.”

Reference

McKay RR, Xie W, Fennessy FM, et al. Results of a phase II trial of intensive androgen deprivation therapy prior to radical prostatectomy (RP) in men with high-risk localized prostate cancer (PC). Presented at the American Society of Clinical Oncology 2020 Virtual Scientific Program held May 29 to 31. Abstract 5503.

https://meetinglibrary.asco.org/record/187058/abstract