Is conclusive proof of efficacy required to show a reasonable expectation of success?
No, conclusive proof of efficacy is not required to show a reasonable expectation of success in patent law. The MPEP 2143.02 cites several court decisions that support this principle:
“Conclusive proof of efficacy is not required to show a reasonable expectation of success. OSI Pharm., LLC v. Apotex Inc., 939 F.3d 1375, 1385, 2019 USPQ2d 379681 (Fed. Cir. 2019) (‘To be clear, we do not hold today that efficacy data is always required for a reasonable expectation of success. Nor are we requiring ‘absolute predictability of success.’)”
The Federal Circuit has consistently rejected the requirement of conclusive proof of efficacy for obviousness. In Acorda Therapeutics, Inc. v. Roxane Lab., Inc., the court stated:
“This court has long rejected a requirement of ‘[c]onclusive proof of efficacy’ for obviousness.”
Instead, what is required is a reasonable expectation of success based on the knowledge available at the relevant time. This allows for some level of uncertainty or unpredictability, as long as there is a reasonable basis to expect that the claimed invention would work as described.
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