The Phase II BATMAN trial (Bipolar Androgen Therapy for Men with Androgen-ablation Nave Prostate Cancer) were previously published. For a study, researchers sought to assess the safety and effectiveness of a treatment plan that involved a lead-in period of androgen deprivation therapy (ADT) lasting 6 months, followed by intervals of bipolar androgen therapy (BAT) and ADT alone lasting three months each. They provide data from more than 5-year follow-ups on the length of further ADT, response to first-line androgen receptor inhibitors, safety, and survival in men treated in the BATMAN trial for castration-sensitive prostate cancer.
To compare overall survival between Responders who attained a PSA level of less than 4 ng/ml after BAT/ADT and Non-Responders who attained a PSA level of more or around 4 ng/ml, univariate Cox regression was used. In addition, the assessment of progression-free (PFS) and overall survival (OS) on BAT, following abiraterone or enzalutamide, and the relationship between PSA peak during BAT and each time to event outcome was done using the Kaplan-Meier method and Cox regression.
The median PFS on ADT for the total group was 47.8 over the median follow-up of 95 months. No one had attained median OS (NR). In contrast to NR (not achieved) for respondents, the median OS for non-responders is 43 months (hazard ratio [HR]: 0.176, P=0.002). The median PFS after BAT was 20.6 months, and the PSA50 and PSA90 responses to abiraterone or enzalutamide were 94.4% and 66.7%, respectively. Patients with a peak PSA level of more or around 9 ng/ml following BAT had a median PFS of 20.6 months as opposed to NR for those with PSA less than 9 ng/ml (HR: 0.122, P<0.001). Patients with a PSA peak of more or around 9 ng/ml had a median OS of 79.6 months compared to NR for patients with a PSA peak of less than 9 ng/ml (HR: 0.409, P=0.135).
In patients with prostate cancer, the use of BAT as a first-line hormone treatment method had no substantial long-term adverse sequelae and had no unfavorable effects on long-term survival. Cycling BAT may lengthen the time that an ADT response lasted and improved the responsiveness to later androgen ablative treatments. Further research was needed to determine whether the PSA increase caused by BAT can predict how long an ADT response would last.