{"entity":{"id":"idea-prostate-bipolar-androgen-therapy-phase-3-on-pfs2","kind":"idea","name":"Take high-dose testosterone to phase 3, with progression-free survival through the second line as the primary endpoint","aka":["bipolar androgen therapy phase 3","supraphysiological testosterone prostate phase 3","BAT resensitisation trial"],"tldr":"Giving men with castration-resistant prostate cancer large doses of the hormone the treatment has spent years removing makes a third of them respond, and makes half of them respond again to the drug that had stopped working. It has never been taken to a definitive trial, partly because the endpoint that shows the benefit is not the one trials usually use.","summary":"RESTORE gave monthly testosterone cipionate 400 mg to 30 men who had progressed on enzalutamide: 9 of 30 (30 percent) had a 50 percent prostate-specific antigen fall, and 15 of 21 (52 percent) responded when re-challenged with enzalutamide afterwards. TRANSFORMER randomised the approach against enzalutamide in 195 men and found progression-free survival of 5.7 months in both arms, but progression-free survival through crossover of 28.2 against 19.6 months in favour of testosterone first (hazard ratio 0.44, P equals 0.02), prostate-specific antigen progression-free survival on enzalutamide of 10.9 months after testosterone against 3.8 months after abiraterone, and quality of life consistently favouring testosterone.\n\nThe drug is an old generic. There is no commercial sponsor with a reason to run the trial, and the primary endpoint that regulators are used to, progression-free survival on the assigned treatment, is precisely the one on which the approach is flat, because the benefit is resensitisation rather than direct cytotoxicity. That combination is why a treatment with a randomised signal and a quality-of-life advantage has sat at phase 2 since 2021. The proposal is a publicly funded phase 3 in asymptomatic men with low-volume castration-resistant disease, powered on progression-free survival through the second line, with overall survival and patient-reported outcomes as key secondaries.\n\nUK and NHS specifics (the National Screening Committee position, NICE technology appraisals and their recommendation numbers, Cancer Drugs Fund status, magnetic resonance imaging and radiotherapy capacity, National Prostate Cancer Audit indicators and trial access) belong on the UK and NHS page for prostate cancer and are not restated here.","asOf":"2026-09-25","links":[],"tags":["prostate-evidence"],"related":["idea-bio1-alternating-schedules","idea-tr1-adaptive-therapy-randomised-phase-2","idea-moon-generics-for-cancer-fund","prostate-roadmap"],"cancers":["prostate","prostate-mcrpc"],"sections":["hormonal"],"technologies":[],"targets":["androgen-receptor"],"drugs":["enzalutamide","abiraterone"],"companies":[],"institutions":["johns-hopkins"],"pathways":[],"terms":["castration-resistance","psa","quality-of-life","bipolar-androgen-therapy","intermittent-androgen-deprivation"],"trials":[],"people":[],"bottlenecks":["b-generic-repurposing","b-incentive-misalignment","b-resistance","b-trial-design","b-toxicity-qol"],"keyPapers":["paper-teply-restore-bipolar-androgen-therapy-lancet-oncol-2018","paper-denmeade-transformer-bipolar-androgen-therapy-jco-2021","paper-chen-androgen-receptor-overexpression-antiandrogen-resistance-nat-med-2004","paper-visakorpi-androgen-receptor-amplification-nat-genet-1995","paper-antonarakis-ar-v7-resistance-nejm-2014"],"journals":[],"dependsOn":[],"notes":[],"hypothesis":"In asymptomatic men with metastatic castration-resistant prostate cancer and no high-risk sites for tumour flare, a strategy of bipolar androgen therapy followed at progression by an androgen receptor pathway inhibitor improves progression-free survival through the second line and patient-reported quality of life against the reverse strategy, without a detriment in overall survival.","rationale":"The mechanism follows directly from the biology of resistance in this disease: castration-resistant cells adapt by amplifying and overexpressing the androgen receptor, which Visakorpi and Chen established, and a cell adapted to a low-ligand environment is vulnerable to a high-ligand one. The clinical signal is randomised, not anecdotal, and it is a sequence effect of 8.6 months in PFS2 with a hazard ratio of 0.44. The quality-of-life direction is unusual: almost every intensification in this disease costs the patient something, and this one does not. The barrier is commercial rather than scientific, which makes it exactly the kind of question a public funder should pick up, and the endpoint problem is soluble by naming PFS2 in the protocol rather than discovering it in the secondary analysis.","test":"A publicly funded randomised phase 3 in asymptomatic men with metastatic castration-resistant prostate cancer, excluding those with more than five visceral sites or bone lesions at risk of fracture, randomised to bipolar androgen therapy followed by an androgen receptor pathway inhibitor at progression, or to an androgen receptor pathway inhibitor followed by bipolar androgen therapy. Primary endpoint progression-free survival through the second line; key secondary endpoints overall survival, patient-reported quality of life and sexual function, and cardiovascular and thromboembolic events. Stratify on prior androgen receptor pathway inhibitor exposure and on AR-V7 status. Roughly 500 men and five years.","maturity":"early-clinical","actor":"research","cost":"medium","horizonYears":6},"route":"/ideas/idea-prostate-bipolar-androgen-therapy-phase-3-on-pfs2/","neighbours":{"idea":[{"id":"idea-moon-generics-for-cancer-fund","kind":"idea","name":"A public fund and label pathway to trial generic drugs against cancer","route":"/ideas/idea-moon-generics-for-cancer-fund/"},{"id":"idea-tr1-adaptive-therapy-randomised-phase-2","kind":"idea","name":"Evolution-guided 'adaptive therapy' dosing tested in randomised phase 2 trials","route":"/ideas/idea-tr1-adaptive-therapy-randomised-phase-2/"},{"id":"idea-bio1-alternating-schedules","kind":"idea","name":"Rotate between drugs on a fixed schedule instead of waiting for failure","route":"/ideas/idea-bio1-alternating-schedules/"}],"roadmap":[{"id":"prostate-roadmap","kind":"roadmap","name":"Prostate cancer roadmap: from Huggins and the discovery that a cancer can depend on a hormone, through the PSA epidemic and what it cost, the androgen receptor drugs, the DNA repair subset and PSMA, to a 2032 registry watch","route":"/roadmaps/prostate-roadmap/"}],"cancer":[{"id":"prostate-mcrpc","kind":"cancer","name":"Metastatic castration-resistant prostate cancer","route":"/cancers/prostate-mcrpc/"},{"id":"prostate","kind":"cancer","name":"Prostate cancer","route":"/cancers/prostate/"}],"section":[{"id":"hormonal","kind":"section","name":"Hormonal Therapy","route":"/fronts/hormonal/"}],"target":[{"id":"androgen-receptor","kind":"target","name":"Androgen receptor","route":"/targets/androgen-receptor/"}],"drug":[{"id":"abiraterone","kind":"drug","name":"Abiraterone acetate","route":"/drugs/abiraterone/"},{"id":"enzalutamide","kind":"drug","name":"Enzalutamide","route":"/drugs/enzalutamide/"}],"institution":[{"id":"johns-hopkins","kind":"institution","name":"Johns Hopkins Hospital / Sidney Kimmel Comprehensive Cancer Center","route":"/institutions/johns-hopkins/"}],"term":[{"id":"bipolar-androgen-therapy","kind":"term","name":"Bipolar androgen therapy (BAT)","route":"/terms/bipolar-androgen-therapy/"},{"id":"castration-resistance","kind":"term","name":"Castration-resistant prostate cancer (CRPC)","route":"/terms/castration-resistance/"},{"id":"intermittent-androgen-deprivation","kind":"term","name":"Intermittent androgen deprivation (IAD)","route":"/terms/intermittent-androgen-deprivation/"},{"id":"psa","kind":"term","name":"PSA (prostate-specific antigen)","route":"/terms/psa/"},{"id":"quality-of-life","kind":"term","name":"Quality of life","route":"/terms/quality-of-life/"}],"bottleneck":[{"id":"b-resistance","kind":"bottleneck","name":"Acquired resistance to every therapy","route":"/bottlenecks/b-resistance/"},{"id":"b-incentive-misalignment","kind":"bottleneck","name":"Incentives reward me-too drugs and marginal gains","route":"/bottlenecks/b-incentive-misalignment/"},{"id":"b-generic-repurposing","kind":"bottleneck","name":"No incentive to repurpose cheap drugs","route":"/bottlenecks/b-generic-repurposing/"},{"id":"b-toxicity-qol","kind":"bottleneck","name":"Toxicity and quality of life are undervalued","route":"/bottlenecks/b-toxicity-qol/"},{"id":"b-trial-design","kind":"bottleneck","name":"Trial design, endpoints and cost","route":"/bottlenecks/b-trial-design/"}],"paper":[{"id":"paper-antonarakis-ar-v7-resistance-nejm-2014","kind":"paper","name":"AR-V7 and resistance to enzalutamide and abiraterone in prostate cancer","route":"/key-papers/paper-antonarakis-ar-v7-resistance-nejm-2014/"},{"id":"paper-visakorpi-androgen-receptor-amplification-nat-genet-1995","kind":"paper","name":"In vivo amplification of the androgen receptor gene and progression of human prostate cancer","route":"/key-papers/paper-visakorpi-androgen-receptor-amplification-nat-genet-1995/"},{"id":"paper-chen-androgen-receptor-overexpression-antiandrogen-resistance-nat-med-2004","kind":"paper","name":"Molecular determinants of resistance to antiandrogen therapy","route":"/key-papers/paper-chen-androgen-receptor-overexpression-antiandrogen-resistance-nat-med-2004/"},{"id":"paper-teply-restore-bipolar-androgen-therapy-lancet-oncol-2018","kind":"paper","name":"RESTORE: bipolar androgen therapy after progression on enzalutamide in metastatic castration-resistant prostate cancer","route":"/key-papers/paper-teply-restore-bipolar-androgen-therapy-lancet-oncol-2018/"},{"id":"paper-denmeade-transformer-bipolar-androgen-therapy-jco-2021","kind":"paper","name":"TRANSFORMER: bipolar androgen therapy versus enzalutamide in asymptomatic metastatic castration-resistant prostate cancer","route":"/key-papers/paper-denmeade-transformer-bipolar-androgen-therapy-jco-2021/"}]}}