Bipolar Androgen Therapy in Metastatic Castration-Resistant Prostate Cancer
Posted: Tuesday, July 7, 2020
For patients with asymptomatic metastatic castration-resistant prostate cancer, bipolar androgen therapy yielded comparable progression-free survival as did enzalutamide in those whose disease was refractory to abiraterone, according to findings from the phase II TRANSFORMER trial presented during the ASCO20 Virtual Scientific Program (Abstract 5517). Samuel R. Denmeade, MD, of the Sidney Kimmel Comprehensive Cancer Center at John Hopkins University, Baltimore, and colleagues noted that patients who received bipolar androgen therapy and then crossed over to enzalutamide had better outcomes than those who received enzalutamide and then bipolar androgen therapy.
“These results support the hypothesis that treatment with [bipolar androgen therapy] is safe, has efficacy, and can restore sensitivity to antiandrogens,” the authors concluded.
In this trial, 94 patients received 400 mg of testosterone cypionate, and 101 patients received 160 mg of enzalutamide. The primary endpoint was clinical or radiographic progression-free survival, and crossover was permitted at disease progression.
Despite being “diametrically opposed therapies,” the authors found that progression-free survival and prostate-specific antigen (PSA) response did not differ significantly between patients treated with bipolar androgen therapy versus enzalutamide. Overall response and overall survival were better with bipolar androgen therapy; for those patients who received that therapy and then crossed over to enzalutamide, the PSA response of at least 50% was 77.8% and the time to PSA disease progression was 10.9 months. Those who received enzalutamide immediately after abiraterone demonstrated a PSA response of 25.3% and the time to PSA disease progression was 3.8 months.
For men who crossed over from bipolar androgen therapy to enzalutamide, the time to PSA disease progression from randomization through crossover was 28.2 months, compared with 19.6 months for those who started with enzalutamide before crossing over. Additionally, for men who crossed over from bipolar androgen therapy to enzalutamide, overall survival was 37.3 months, versus 28.6 months for those who received enzalutamide but did not cross over.
Disclosure: For full discourses of the study authors, visit coi.asco.org.
