Eli Lilly in Prozac patents fight

Barr Pharmaceuticals has announced it is being sued by Eli Lilly over the patent for Prozac weekly capsules. Barr says the move will mark the start of Barr’s patent challenge for the anti-depressant, which made billions of dollars for Lilly during the 1990s.

Fluxotine hydrochloride, the active ingredient in Prozac, is already made by generic manufacturers following an earlier patent judgment between Barr and Lilly in 2001, although the patent for the Prozac weekly patent is still retained by Lilly. The weekly capsule form of the drug is administered to prevent depressive relapse in patients whose symptoms have stabilised.

Barr says the purpose of Lilly’s lawsuit is to prevent the generic manufacturer from commercialising Prozac. The company, which already produces generic Prozac tablets and capsules in various strengths, also produces many other generic products, including acne and contraceptive drugs. Under the name Duramed, the company also has a range of proprietary products.

Last week a jury ruled against Lilly for patent infringements caused by their drugs Evista and Xigris. The suit, filed by Ariad Pharmaceuticals, was described by Robert A. Armitage, Lilly’s senior vice-president and counsel, as akin to forcing hydroelectric plants to pay patent royalties for their use of gravity.

He said: “In my more than thirty years of experience in patent law, which includes involvement in dozens of patent lawsuits, I’ve never seen a jury verdict with which I so strongly disagree: the finding of infringement stands at odds with the most basic premise of the patent system.”

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