TRANSFORMER: A Randomized Phase II Study Comparing Bipolar Androgen Therapy Versus Enzalutamide in Asymptomatic Men With Castration-Resistant Metastatic Prostate Cancer

Samuel R. Denmeade, Hao Wang, Neeraj Agarwal, David C. Smith, Michael T. Schweizer, Mark N. Stein, Vasileios Assikis, Przemyslaw W. Twardowski, Thomas W. Flaig, Russell Z. Szmulewitz, Jeffrey M. Holzbeierlein, Ralph J. Hauke, Guru Sonpavde, Jorge A. Garcia, Arif Hussain, Oliver Sartor, Shifeng Mao, Harry Cao, Wei Fu, Ting WangRehab Abdallah, Su Jin Lim, Vanessa Bolejack, Channing J. Paller, Michael A. Carducci, Mark C. Markowski, Mario A. Eisenberger, Emmanuel S. Antonarakis

Research output: Contribution to journalArticlepeer-review


PURPOSE Prostate cancer (PCa) becomes resistant to androgen ablation through adaptive upregulation of the androgen receptor in response to the low-testosterone microenvironment. Bipolar androgen therapy (BAT), defined as rapid cycling between high and low serum testosterone, disrupts this adaptive regulation in castration-resistant PCa (CRPC). METHODS The TRANSFORMER (Testosterone Revival Abolishes Negative Symptoms, Fosters Objective Response and Modulates Enzalutamide Resistance) study is a randomized study comparing monthly BAT (n 5 94) with enzalutamide (n 5 101). The primary end point was clinical or radiographic progression-free survival (PFS); crossover was permitted at progression. Secondary end points included overall survival (OS), prostate-specific antigen (PSA) and objective response rates, PFS from randomization through crossover (PFS2), safety, and quality of life (QoL). RESULTS The PFS was 5.7 months for both arms (hazard ratio [HR], 1.14; 95% CI, 0.83 to 1.55; P 5 .42). For BAT, 50% decline in PSA (PSA50) was 28.2% of patients versus 25.3% for enzalutamide. At crossover, PSA50 response occurred in 77.8% of patients crossing to enzalutamide and 23.4% to BAT. The PSA-PFS for enzalutamide increased from 3.8 months after abiraterone to 10.9 months after BAT. The PFS2 for BAT→enzalutamide was 28.2 versus 19.6 months for enzalutamide→BAT (HR, 0.44; 95% CI, 0.22 to 0.88; P 5 .02). OS was 32.9 months for BAT versus 29.0 months for enzalutamide (HR, 0.95; 95% CI, 0.66 to 1.39; P 5 .80). OS was 37.1 months for patients crossing from BAT to enzalutamide versus 30.2 months for the opposite sequence (HR, 0.68; 95% CI, 0.36 to 1.28; P 5 .225). BAT adverse events were primarily grade 1-2. Patient-reported QoL consistently favored BAT. CONCLUSION This randomized trial establishes meaningful clinical activity and safety of BAT and supports additional study to determine its optimal clinical integration. BAT can sensitize CRPC to subsequent antiandrogen therapy. Further study is required to confirm whether sequential therapy with BAT and enzalutamide can improve survival in men with CRPC.

Original languageEnglish (US)
Pages (from-to)1371-1382
Number of pages12
JournalJournal of Clinical Oncology
Issue number12
StatePublished - Apr 20 2021

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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