Some men with advanced prostate cancer have been given the antifungal treatment Ketoconazole (Keto) as a second line hormone treatment. Like Keto, this newer hormone treatment that is now available, Abiraterone acetate (AA) (Zytiga) works by inhibiting CYP17, the rate-limiting enzyme in androgen biosynthesis.

The question being asked, if Keto has failed ,given its similar mode of action, can Zytiga still be an active agent? In the clinical trials for Zytiga men with prior keto treatment were excluded, so the utility of Zytiga after Keto is not well understood.

In a prospective study the researchers evaluated the efficacy of Zytiga in men who had received prior Keto. The trial consisted of men with progressive castration-resistant prostate cancer (mCRPC) who had prior Keto therapy for 28 days or more and who were treated with Zytiga at 1,000 mg and prednisone 5 mg daily.

Serum androgen levels, including dehydroepiandrosterone (DHEA), were measured at baseline and during treatment for exploratory analyses. Radiographic progression-free survival (rPFS) was defined as freedom from: death, radiographic progression, or unequivocal clinical progression.

The trial enrolled forty two men. Me