Methylnaltrexone - USA

On May 01, 2018, New Jersey district court granted a motion for partial summary judgment of validity of a formulation patent for RELISTOR® (methylnaltrexone bromide) Injection.

This is a Hatch-Waxman case involving a patent dispute regarding Defendants Mylan Inc., Mylan Laboratories Ltd., Mylan Pharmaceuticals, Inc., and Actavis LLC (collectively, “Defendants”) seek to make and sell a generic version of Plaintiff’s Relistor® (methylnaltrexone bromide) pharmaceutical product prior to the expiration of the relevant patents. Plaintiffs’ motion concerns claim 8 of US Patent No. 8,552,025 (the “’025 patent”). Plaintiffs, Progenics Pharmaceuticals, Inc., Salix Pharmaceuticals, Inc., Valeant Pharmaceuticals International, Inc., and Wyeth LLC (collectively, “Plaintiffs.”) moved for partial summary judgment on Defendants’ affirmative defense to infringement of invalidity due to obviousness. Plaintiffs contended that, as to claim 8, Defendants cannot prove invalidity due to obviousness.

Claim 8 relates to stable pharmaceutical preparation comprising a solution of methylnaltrexone comprises a pH between about 3.0 and about 4.0 & wherein the preparation is stable to storage for 24 months at about room temperature.

In moving for summary judgment, Plaintiffs made three arguments: 1) Defendants have failed to identify any motivation to modify the prior art methylnaltrexone products; 2) Defendants cannot establish that the “stable to storage for 24 months” element was known in the prior art; and 3) Defendants cannot prove their “obvious to try” theory. Court said that based on the record, the prior art did not teach how to formulate an injectable pharmaceutical solution that is stable for 24 months. Defendants have offered no evidence to the contrary. Thus, while the idea of an injectable pharmaceutical solution stable for 24 months seems unlikely to have been unknown, there is no evidence before this Court that the art taught how to make one. The evidence of record showed that the prior art taught a variety of techniques for improving the stability of such solutions, but there is no evidence that anyone had ever achieved an injectable pharmaceutical solution stable for 24 months. Court further said that, for the principle of overlapping ranges to apply, the difference between the claimed invention and the prior art must be the range or value of a particular variable. The differences between claim 8 and each of the prior art references (Bahal ’154, Oshlack ’111, and Fawcett 1997) is greater than the value of the pH variable. Thus Court was not persuaded, as a matter of law, that any of the cited prior art references which teach the use of naloxone and naltrexone presents an overlapping pH range sufficient to make out a prima facie case of obviousness. Defendants have not persuaded the Court that any of the prior art references dealing with naloxone and naltrexone – that is, Bahal ’154, Oshlack ’111, and Fawcett 1997 – taught something that would have made claim 8 a predictable result.

The motion for partial summary judgment of validity of claim 8 thus granted.