{"entity":{"id":"cou-aa-301","kind":"trial","name":"COU-AA-301","aka":["COU-AA-301","abiraterone after docetaxel"],"tldr":"Proved that prostate cancer which has stopped responding to standard hormone therapy is still driven by androgens, by blocking the enzyme that makes them and adding about four months of life.","summary":"The premise of castration-resistant prostate cancer used to be that the disease had escaped hormonal control. COU-AA-301 tested the opposite hypothesis, that androgens made outside the testes, in the adrenal glands and the tumour itself, keep driving it, and that blocking CYP17 would work.\n\nIt randomised 1,195 men who had already received docetaxel 2:1 to abiraterone acetate 1000 mg daily with prednisone (797) or placebo with prednisone (398). At a median 12.8 months, overall survival was 14.8 against 10.9 months, hazard ratio 0.65 (95 percent confidence interval 0.54 to 0.77, p<0.001). The data were unblinded at the interim analysis because the result exceeded the preplanned stopping criteria. Time to PSA progression was 10.2 against 6.6 months (p<0.001), radiographic progression-free survival 5.6 against 3.6 months (p<0.001) and PSA response 29 against 6 percent (p<0.001).\n\nThe side effects follow from the mechanism: blocking CYP17 raises mineralocorticoids, so fluid retention, hypertension and hypokalaemia were more common with abiraterone, which is why it is given with a steroid.\n\nIn England NICE TA259 recommends abiraterone with prednisone or prednisolone after one docetaxel-containing regimen, subject to the commercial access arrangement.","status":"positive","asOf":"2026-09-25","links":[{"label":"ClinicalTrials.gov NCT00638690","url":"https://clinicaltrials.gov/study/NCT00638690"},{"label":"COU-AA-301 (New England Journal of Medicine 2011)","url":"https://doi.org/10.1056/NEJMoa1014618"},{"label":"NICE TA259: abiraterone for castration-resistant metastatic prostate cancer previously treated with a docetaxel-containing regimen","url":"https://www.nice.org.uk/guidance/ta259"}],"tags":[],"related":[],"cancers":["prostate","prostate-mcrpc"],"sections":[],"technologies":["androgen-deprivation"],"targets":["androgen-receptor"],"drugs":["abiraterone","prednisone"],"companies":["johnson-johnson"],"institutions":[],"pathways":[],"terms":["arpi","castration-resistance","psa50"],"trials":["cou-aa-302","affirm","tax-327"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"nct":"NCT00638690","phase":"3","setting":"Metastatic castration-resistant prostate cancer after docetaxel: prednisone 5 mg twice daily for everyone, with abiraterone acetate 1000 mg daily or placebo, randomised 2:1, with overall survival as the primary endpoint","sponsor":"Cougar Biotechnology, later Janssen","result":"Median overall survival 14.8 against 10.9 months (hazard ratio 0.65, 95 percent confidence interval 0.54 to 0.77) with abiraterone after docetaxel; PSA response 29 against 6 percent.","yearReported":2011,"enrolled":1195,"enrolledBasis":"registry","outcomes":[{"endpoint":"Overall survival (median)","primary":true,"unit":"months","arms":[{"name":"Abiraterone acetate with prednisone","n":797,"value":14.8},{"name":"Placebo with prednisone","n":398,"value":10.9}],"hr":0.65,"ci":[0.54,0.77],"p":"<0.001","source":"https://doi.org/10.1056/NEJMoa1014618"},{"endpoint":"Radiographic progression-free survival (median)","unit":"months","arms":[{"name":"Abiraterone acetate with prednisone","n":797,"value":5.6},{"name":"Placebo with prednisone","n":398,"value":3.6}],"p":"<0.001","source":"https://doi.org/10.1056/NEJMoa1014618"}],"replication":"AFFIRM found the same in the same setting with enzalutamide (18.4 against 13.6 months); COU-AA-302 moved abiraterone before chemotherapy."},"route":"/trials/cou-aa-301/","neighbours":{"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/"}],"technology":[{"id":"androgen-deprivation","kind":"technology","name":"Androgen deprivation & AR pathway inhibitors","route":"/technologies/androgen-deprivation/"}],"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":"prednisone","kind":"drug","name":"Prednisone","route":"/drugs/prednisone/"}],"company":[{"id":"johnson-johnson","kind":"company","name":"Johnson & Johnson","route":"/companies/johnson-johnson/"}],"term":[{"id":"arpi","kind":"term","name":"Androgen receptor pathway inhibitor (ARPI)","route":"/terms/arpi/"},{"id":"castration-resistance","kind":"term","name":"Castration-resistant prostate cancer (CRPC)","route":"/terms/castration-resistance/"},{"id":"psa50","kind":"term","name":"PSA50 / PSA90 response","route":"/terms/psa50/"},{"id":"prostate-crpc-sequencing","kind":"term","name":"What follows what in castration-resistant prostate cancer","route":"/terms/prostate-crpc-sequencing/"}],"trial":[{"id":"affirm","kind":"trial","name":"AFFIRM","route":"/trials/affirm/"},{"id":"cou-aa-302","kind":"trial","name":"COU-AA-302","route":"/trials/cou-aa-302/"},{"id":"tax-327","kind":"trial","name":"TAX 327","route":"/trials/tax-327/"}]}}