Neoadjuvant androgen deprivation therapy with enzalutamide active in high-risk localized prostate cancer
CHICAGO — Six months of neoadjuvant androgen deprivation therapy with enzalutamide demonstrated activity among men with high-risk localized prostate cancer, according to study results presented at ASCO Annual Meeting.
A small number of patients achieved exceptional responses, according to researchers.
Up to 10% of patients with localized disease who undergo neoadjuvant androgen deprivation therapy with abiraterone acetate (Zytiga, Janssen) and prednisone achieve pathological complete response.
David James VanderWeele, MD, PhD, assistant clinical investigator in Laboratory of Genitourinary Cancer Pathogenesis at NIH, and colleagues conducted a single-institution trial to evaluate the efficacy of neoadjuvant androgen deprivation therapy with goserelin plus 160 mg daily enzalutamide (Xtandi; Astellas, Pfizer) for patients with high-risk localized disease.
All patients underwent MRI/transrectal ultrasound-guided fusion biopsy at screening, as well as repeat multiparametric MRI followed by radical prostatectomy after 6 months of therapy.
Investigators also assessed the ability of posttreatment multiparametric MRI to measure response.
At the time of analysis, 22 women had completed therapy and undergone radical prostatectomy.
Baseline characteristics appeared typical of those with high-risk disease, according to researchers. Median PSA was 10.3 ng/mL (range, 2.1-985.9) and clinical stage by multiparametric MRI was cT2 to cT4.
After 6 months of therapy but prior to radical prostatectomy, median PSA was 0.02 ng/mL (range, < .02-0.35).
On final pathology, no patients were upstaged and five patients (23%) were unchanged.
Fifteen patients (77%) were downstaged, including four (18%) who achieved partial complete response or near-partial complete response (residual cancer burden < 0.001 cc). Of the four who achieved partial complete response or near-partial complete response, one was cT0 on posttreatment multiparametric MRI, one was cT2, and two were cT3. Another patient who achieved radiographic complete response was pT3a on pathological review.
Five of nine patients who had bulky nodes at baseline were downstaged to pN0. Six of the nine patients who had p%3 disease at time of prostatectomy were cT3 on posttreatment multiparametric MRI.
“Standard analysis of multiparametric MRI identifies most patients with persistent T3 disease but does not reliably identify exceptional responses,” VanderWeele and colleagues wrote. “Evaluation of molecular characteristics that predict exceptional response or intrinsic resistance is ongoing.” – by Mark Leiser
For more information:
VanderWeele DJ, et al. Abstract 5082. Presented at: ASCO Annual Meeting; June 1-5, 2018; Chicago.
Disclosures: VanderWeele reports no relevant financial disclosures. Please see the abstract for all other authors’ relevant financial disclosures.