Prima facie obviousness of pharmaceutical patents implications for enantiomers

Innovator pharmaceutical companies file primary patents to protect new molecular entities (NME) and secondary patents to protect NMEs in various forms. “Non-obviousness” is the most critical criterion for patentability of both. A showing of “prima facie obviousness” shifts the onus to the patentee to prove that the claimed invention is non-obvious. This paper presents a framework to analyze the non-obviousness of the claims. More particularly it explains why the enantiomers are always prima facie obvious and how to overcome the same. The utility of the framework is demonstrated by analyzing the non-obviousness of Levofloxacin and other enantiomers.