GATT Provision on Generics Causes Uproar : Drugs: At issue is whether patents should last 20 years, as trade agreement says, or 17 years, as U.S. law says.

A senator asserted Thursday that Americans could wind up paying $6 billion more for their medicines than they otherwise might because of a provision in the new world trade agreement that extends the patents of brand-name drugs.

Pharmaceutical giants are battling consumer groups and generic competitors before the Food and Drug Administration to determine whether they’ll be able to pocket the difference.

At issue is whether the General Agreement on Tariffs and Trade will keep lower-priced generic drugs from competing with more than 100 brand-name versions as quickly as generic companies and consumers had hoped.

“What’s going to happen is we’re seeing American consumers paying . . . higher drug prices for a much longer period of time,” said Sen. David Pryor (D-Ark.), who, with five other senators, urged the FDA on Thursday to side with the generic industry.

When GATT goes into effect in June, all new patents will last 20 years. Current U.S. law says patents last just 17 years. GATT also allows the life of some current patents to be extended to 20 years.

For medicines, that means 109 brand-name drugs could each get up to three more years of sales before they face competition from generic versions. For example, the patent on the ulcer medication Zantac, the world’s best-selling drug, was to expire in December, but manufacturer Glaxo Inc. says that with GATT, Zantac will be protected until July, 1997.

A University of Minnesota study says Americans could pay $6 billion more for those drugs during the next 20 years.