Procter & Gamble Co. v. Teva Pharmaceuticals USA, Inc.
United States Court of Appeals for the Federal Circuit
566 F.3d 989 (2009)
P&G (plaintiff) held a patent on risedronate, the active ingredient in its osteoporosis drug Actonel, discovered only after unsuccessful testing of hundreds of related bisphosphonate compounds including structurally similar 2-pyr EHDP and 4-pyr EHDP, both of which failed despite their structural similarity; Teva (defendant), seeking to market a generic, argued the patent was obvious in light of P&G's own earlier patent listing 2-pyr EHDP, and the district court, crediting P&G's expert testimony on the field's unpredictability, upheld the patent's validity.
Whether, in the context of chemical inventions, unpredictability of the compounds at issue may preclude a successful obviousness challenge, even where the claimed compound is structurally similar to prior art.