A review of the Hammersmith Hospital, St. Bartholomew's Hospital, and Institute of Urology studies of buserelin in advanced prostatic cancer.

This article reviews studies by our group on the role of LHRH agonists in prostatic cancer. Early work showed these agents to be an effective treatment of prostatic cancer, establishing an intranasal dosage regimen that suppressed serum testosterone into the castrate range. Although treatment was without cardiovascular toxicity, other side effects of agonist therapy were noted. An initial exacerbation of disease resulted from the stimulatory effects of these compounds. As a result, combination therapies with antiandrogens in the early phase of treatment is recommended. A long-term follow-up of patients who had received intranasal buserelin demonstrated a failure of suppression of the pituitary-gonadal axis. This was thought to represent difficulty in complying with intranasal treatment or true escape of the axis from agonist control. Against this background, depot preparations of buserelin have been investigated. Two series of implants were studied. The PHB series, although difficult to administer, have provided pharmacological and endocrine data that have allowed for the introduction of the injectable P series implants. These preparations, which are designed to be administered once every 2 months, provide effective suppression of testosterone over this period. Such formulations provide an obvious advantage over conventional treatment regimens.