Pfizer, Inc. v. Ranbaxy Laboratories, Ltd. atorvastatin calcium

Case History In an attempt to protect Lipitor from generic competition, Pfizer sued Ranbaxy in district court asserting, in part, that Ranbaxy infringed upon dependent Claim 6 of U.S. Patent No. 5,273,995 ( 995). 

Pfizer won at the district court level, but lost on appeal at the Federal Circuit, in part because Claim 6 was not written in proper form [11]. This case presents an excellent example of the reach through effect how small actions early on in the patent process can have large consequences in litigation. 

Analysis The active ingredient in Lipitor is atorvastatin calcium. Pfizer lost because of a deficiency in the way dependent Claim 6 related to Claims 1 and 2. The following chart is presented to help understand how this happened  

Suggested Best Practices for Chemists 1. Claims in a patent application tend to begin broadly and then narrow down to important individual compounds. Scrutinize application claims to make sure the most important compounds (e.g., clinical candidates and backups) are individually claimed. One important compound = one claim. 

To avoid legal glitches when claiming compounds, claim important compounds individually in independent claims. It costs more up front, but helps avoid expensive and potentially catastrophic patent defeating legal glitches later. If you do use dependent claims, make them all dependent on a broad, independent Claim 1. 

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