Nonobviousness of pharmaceutical inventions: implications for patent prosecution and litigation.

Nonobviousness is the most critical patentability criterion. Patents covering new molecular entities and second-generation molecules in the pharmaceutical industry are often challenged for obviousness during prosecution and/or litigation. In such situations, the patentee has to either reject or rebut the same by clear and convincing evidence or demonstrate unexpected results, to establish nonobviousness. This paper tries to show how the lead compound requirement is consistent with 35 U.S.C. § 103; the obviousness challenge can be overcome; the two-prong approach is consistent with the Supreme Court's KSR v. Teleflex, 2007 (KSR) decision. The showing is illustrated with the analysis of new molecular entities in the proton-pump inhibitor family.