26Nov 2019

In a recent case, Idenix Pharmaceutical LLC v. Gilead Sciences Inc. (Fed. Cir. 2019), the Federal Circuit affirmed a decision from the District Court invalidating a patent for lack of written description and enablement.   

The patent claims were directed to a method of treating hepatitis C with a purine or pyrimidine beta-D-2-methyl-ribofuranosyl nucleoside.

According to the District Court, and subsequently the Federal Circuit, the specification did not provide guidance for the many thousands of compounds failing within the scope of the claims.

The Federal Circuit held that the patent lacked an adequate written description because it did not adequately describe which nucleosides were effective in the treatment of Hepatitis C and that the specification only provided a starting point for additional research.

Moreover, since there was no specific description of a species or of a number of species defining the genus claimed, or sufficient disclosure on the structure/function relationship of the species, the Federal Circuit held that the specification failed to satisfy the written description requirement. That is, there was no evidence that the patents’ inventors were in possession of the claimed subject matter.

Judge Pauline Newman dissented that it was incorrect to invalidate the claims on the basis of unclaimed chemical variants which were not described, synthesized, or tested for anti-viral activity. Thus, it was her opinion that the claims should have been interpreted to be limited to the small number of species disclosed in the specification, which then were enabled and adequately described. According to Judge Newman, the majority’s enablement theory requires description of “unclaimed and unsupported subject matter.”  

According to the dissenting Judge, the claims were limited by what is exemplified in the specification, wherein interpreting claim scope necessarily restricted the scope of that disclosure.

Please contact me at silvia@salvadorilaw.com with questions or comments.

Silvia Salvadori, PhD

Silvia Salvadori, PhD