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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.
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.
It 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).
The 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.
In England NICE TA259 recommends abiraterone with prednisone or prednisolone after one docetaxel-containing regimen, subject to the commercial access arrangement.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.
1,195 enrolled.
| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Overall survival (median)primary | Abiraterone acetate with prednisone | 797 | 14.8 months | 0.65 (0.54 to 0.77) | <0.001 | link |
| Placebo with prednisone | 398 | 10.9 months | ||||
| Radiographic progression-free survival (median) | Abiraterone acetate with prednisone | 797 | 5.6 months | - | <0.001 | link |
| Placebo with prednisone | 398 | 3.6 months |
Shares COU-AA-302, AFFIRM, PSA50 / PSA90 response, Androgen receptor pathway inhibitor (ARPI).
Shares AFFIRM, Androgen receptor pathway inhibitor (ARPI), What follows what in castration-resistant prostate cancer, Abiraterone acetate.
Shares AFFIRM, PSA50 / PSA90 response, Androgen receptor pathway inhibitor (ARPI), Castration-resistant prostate cancer (CRPC).
Shares COU-AA-302, Androgen receptor pathway inhibitor (ARPI), Prednisone, Castration-resistant prostate cancer (CRPC).
Shares PSA50 / PSA90 response, TAX 327, Prednisone, Castration-resistant prostate cancer (CRPC).
Shares Abiraterone acetate, Prednisone, Androgen deprivation & AR pathway inhibitors, Metastatic castration-resistant prostate cancer.
Shares Abiraterone acetate, Prednisone, Androgen deprivation & AR pathway inhibitors, Johnson & Johnson.
Shares PSA50 / PSA90 response, What follows what in castration-resistant prostate cancer, Prednisone, Castration-resistant prostate cancer (CRPC).