Simultaneous administration of pure antiandrogens, a combination necessary for the use of luteinizing hormone-releasing hormone agonists in the treatment of prostate cancer.

Although castration levels of serum androgens are consistently achieved after 2-3 weeks of treatment with luteinizing hormone-releasing hormone (LHRH) agonists, the administration of these peptides alone in adult men is always accompanied by a transient increase in plasma testosterone and dihydrotestosterone levels, which lasts for 5-15 days at the beginning of treatment and is accompanied by disease flare-up in some cases, thus seriously limiting the acceptability of this otherwise efficient and well-tolerated treatment. The present data show that the simultaneous administration of a pure antiandrogen neutralizes the influence of the transient increase in serum androgens on prostate cancer, as indicated by the 60% decrease in serum prostatic acid phosphatase observed within 5 days of combined treatment with an LHRH agonist and a pure antiandrogen. The addition of a pure antiandrogen thus makes fully acceptable the use of LHRH agonists as an advantageous substitute for surgical castration and estrogens in the treatment of prostate cancer.