US APPROVAL FOR MERCK'S PROSTATE DRUG

Merck has received approval in the USA to market its 5-alpha reductase inhibitor, Proscar (finasteride), for the treatment of benign prostatic hyperplasia. The development comes four months after an advisory panel to the Food and Drug Administra-tion recommended its approval. Merck has forecast the launch of the drug for July, and the speed of the introduction prompted active trading in the company's shares.

The news has received mixed responses from pharmaceutical industry analysts, however. Several believe that the drug may achieve blockbuster status, bringing in between $1 billion and $2 billion in annual revenues within five years. But others are less convinced, considering that the high claims being put forward for the drug both by the company and the financial community may be hard to live up to.

Drug May Disappoint The reservations appear to center on the observation that in clinical trials only 31% of men reported significant symptomatic relief, although 57% reported some benefit. Moreover, the drug takes some time to have an effect, so symptomatic relief will not be apparent until Proscar has been given for at least six months. It is unclear what effect this delay could have on patient compliance, or whether it may encourage men to opt instead for the "quick fix" of surgical treatment. According to company estimates, over ten million men suffer from benign prostatic hyperplasia in the USA.