An experimental drug developed by Merck & Co. shrinksenlarged prostate glands and shows promise of halting theprogression of benign prostate enlargement, which affects themajority of men over age 50.

Finasteride, trade named Proscar, reduced prostate gland sizeby at least 20 percent in more than half of treated patients,said Dr. Elizabeth Stoner, a senior director of clinical researchat the Rahway, N.J., company.

Proscar works by blocking an enzyme, 5-alpha reductase, thattriggers production of dihydrotestosterone (DHT), the keysubstance that promotes prostate enlargement," she said.

A once-daily oral dose reduced DHT levels by 70 percent overthe 12-month controlled study, and the improvement wasmaintained for up to two years. "At these low levels of DHT,the potential for prostate growth is dramatically reduced, andour clinical data suggest that Proscar can halt the progressionof the disease, Stoner said.

Proscar also relieved urinary symptoms associated with thedisease, known as benign prostatic hyperplasia. The resultswere reported Sunday at the annual meeting of the AmericanUrological Association.

In April, Merck filed a new drug application with the Food andDrug Administration and has begun filing marketingapplications abroad.

Finasteride will be marketed both by Merck and by Du PontPharma in Germany, France, Italy, Spain and the UnitedKingdom. Du Pont Pharma, the European subsidiary of the DuPont Merck Pharmaceutical Co., will use its own brand namefor the drug.

Merck common stock (NYSE:MRK) closed at $116.13, down$2.13, on Monday.

(c) 1997 American Health Consultants. All rights reserved.