Affirming a Patent Trial and Appeal Board (PTAB) decision finding claims directed to an epilepsy drug patentable, the US Court of Appeals for the Federal Circuit found that a skilled artisan would not have been motivated to modify a prior art compound when the modification would improve some characteristics of the compound but worsen others. Mylan Pharm. Inc. et al. v. Research Corp. Techs., Inc., Case Nos. 17-2088, -2089, -2091 (Fed. Cir. Feb. 1, 2019) (Lourie, J).

Research Corporation Technologies (RCT) owns a patent that discloses and claims enantiomeric compounds and pharmaceutical compositions useful in the treatment of epilepsy and other central nervous system disorders. Argentum Pharmaceuticals petitioned for inter partes review (IPR) of RCT’s patent based on a combination of references. Mylan Pharmaceuticals, Breckenridge Pharmaceutical and Alembic Pharmaceuticals subsequently filed their own petitions and moved to join the IPR proceedings filed by Argentum, which the PTAB allowed.

During the PTAB proceeding, the petitioners argued that there was a motivation to modify the lead compound in one of the references to improve the compound’s stability. The petitioners acknowledged, however, that the modified compound would have slightly degraded potency compared to the unmodified compound. RCT responded by stating that there was no evidence that the unmodified compound was unstable, and that a person of ordinary skill would consider all of a compound’s characteristics—such as an acceptable level of stability of the unmodified compound and degraded potency of the modified compound—together before making any modification. The PTAB agreed with RCT, finding the claims patentable because the petitioners failed to establish that a person of ordinary skill in the art would have been motivated to modify a lead compound based on the teaching of a second prior art reference. The joined petitioners appealed.

RCT argued that Mylan, Breckenridge and Alembic did not have standing to appeal since Argentum, the party that filed and argued the IPR, was not appealing, and because the joined parties were limited to an “understudy” role during the IPR proceedings. Specifically, RCT argued that the joined parties were limited to an understudy role because they were joined more than one year after an infringement action was brought against them. RCT argued that allowing the joined parties to appeal the IPR decision would be an end run around the one-year statutory time limit of 35 USC § 315 for filing an IPR.

The Federal Circuit disagreed, finding that Mylan, Breckenridge and Alembic were properly joined as “parties” in the IPR under § 315 and therefore were qualified to appeal the IPR decision as “any party” under § 319. To find otherwise, the Court stated, would require reading the word “party” differently between §§ 315 and 319.

Turning to the non-obviousness finding, the Federal Circuit concluded that the PTAB’s decision was supported by substantial evidence, and found that there was no evidence that the unmodified lead compound had an unacceptable level of stability. The Court further found that even if a person of ordinary skill would have been motivated to modify the lead compound to improve stability, the degraded potency of the modified compound would have reasoned against any such modification. The Court therefore found that a person of ordinary skill would not have been motivated to modify a compound to improve a characteristic that was not a problem in a manner that would also degrade another characteristic of the compound.