At the ASCO Annual meeting in Orlando Florida, Cougar Biotechnology, Inc. announced perliminary results from their ongoing Phase II clinical trials of their much discussed investigational drug abiraterone acetate (CB7630). The company released some preliminary encouraging data in three separate poster presentations.

First, I want to tell you what abiraterone acetate is.

In scientific jargon it is an orally active acetate salt of the steroidal compound abiraterone with antiandrogen activity. Abiraterone inhibits the enzymatic activity of steroid 17alpha-monooxygenase (17alpha-hydrolase/C17,20 lyase complex), a member of the cytochrome p450 family that catalyzes the 17alpha-hydroxylation of steroid intermediates involved in testosterone synthesis.

In plain English, it is an antiandrogen like leuprolide (Lupron, Viadur, or Eligard), goserelin (Zoladex), triptorelin (Trelstar Depot), and abarelix (Plenaxis). However, it seems to operate using a different biological pathway so it can work even when these other drugs have stopped functioning. Administration of abiraterone acetate suppresses testosterone production by both the testes and the adrenals.


Poster I

Preliminary results of a phase II multicenter study of chemotherapy-naïve castration-resistant prostate cancer (CRPC) patients not exposed to ketoconazole, treated with abiraterone acetate plus prednisone (COU-AA-002)

This Phase II clinical