Prozac Maker Files Patent Suit

Eli Lilly & Co. is fighting to protect Prozac from a generic drug manufacturer that wants to market a cheaper version of the top-selling antidepressant.

Lilly filed a patent infringement lawsuit in U.S. District Court in Indianapolis against Barr Laboratories of Pomona, N.Y.

Barr, a leading maker of low-cost generic drugs, contends the patents protecting Prozac from copies are invalid.

It asked the Food and Drug Administration in December for permission to sell generic Prozac, called fluoxetine.

Prozac has become a best-selling drug since its introduction in 1988. It usually costs more than $70 for a month’s supply, bringing Lilly more than $2 billion in worldwide sales last year.

Lilly’s 20-year U.S. patent on fluoxetine is not due to expire until Feb. 2, 2001, and a second patent for the way the drug acts inside the body is valid until Dec. 2, 2003, said company spokesman Ed West.

The legal battle over whether Barr will be able to market its version of the drug is likely to take two to three years, but still could give the company a head start on other generic manufacturers.

Drug companies say breakthrough drugs such as Prozac need long-lasting patent protection to recoup the estimated $500-million cost of bringing a new drug to market.