Intellectual Property Law

When compounds in a class have divergent properties, positional isomer not obvious

By McKee, Voorhees & Sease, P.L.C.

In a decision Wednesday, the Federal Circuit affirmed a district court's determination that the asserted claims in a pharmaceutical patent were not proven obvious.  As is common in pharmaceutical cases, the defendant filed an ANDA asserting the patent covering the compound and its use was invalid, and in the ensuing infringement suit admitted its proposed generic drug met the claim limitations.  The district court specifically held the prior art did not suggest the closes prior art compound as a potential "lead compound," as the various members of the class of compounds had unpredictable properties rendering the claimed compound's beneficial properties unexpected, and secondary considerations of commercial success and long-felt need confirmed the defendant's failure to prove the claims obvious.  The district court also rejected a separate argument of obviousness-type double patenting based on an expired patent also owned by the patentee.

The Federal Circuit affirmed.  Under Takeda, the court observed obviousness for structurally similar chemical compounds depends on one of ordinary skill in the art selecting the asserted prior art compound as the "lead compound," or the starting point for further experimentation.   Here, the court did not reach the question, as it determined that even if the closest prior art compound was selected, the defendant has not shown obviousness.  There was simply no reason shown why one of ordinary skill in the art would modify even the closest compound to produce the claimed compound (a positional isomer) given the inherent unpredictability of the physical-chemical, biological, and therapeutic characteristics of the individual compounds in the class.  The court also cited its recent Kubin decision, observing there was "no credible evidence that the structural modification was routine."  Further, there was evidence of both commercial success ($2.7 billion in sales) and long-felt need.  As a result, the court affirmed the district court's determination that the claims had not been proven obvious.

Similarly, the court affirmed the finding of no obviousness-type double patenting.  Here, the prior art patent claimed intermittent dosing of compounds in the same class as the claimed compound (to compensate for side effects), whereas the asserted claims are directed to the compound itself (both isolated and in a pharmaceutical composition) and using the compound to treat osteoporosis.  There was no clear and convincing evidence of overlap between the patents, so there was no double patenting.

More detail of Procter & Gamble Co. v. Teva Pharms. USA, Inc. after the jump.

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Full post as published by FileWrapper on May 18, 2009 (boomark / email).