## Facts

- Inventors sought patent claims for methods and hybrid vectors to express a predetermined protein in bacteria by fusing a heterologous gene to a substantial portion of an indigenous bacterial gene.
- The claims described deleting the indigenous gene’s normal termination signal and linking the heterologous gene in proper orientation and the same reading frame to permit translational readthrough and expression of a fused protein intended to stabilize the target protein.
- A narrower claim focused on an *E. coli* plasmid using regulatory elements and a substantial portion of the *E. coli* beta-galactosidase gene lacking its termination signal, fused in-frame to a heterologous gene.
- The PTO rejected the claims as obvious under 35 U.S.C. § 103 based on (1) a scientific paper authored by two coinventors published more than one year before the application filing date and (2) the Bahl, Marians & Wu publication.
- Applicants argued the earlier paper did not make the invention obvious because the specific claimed vector and method had not actually been carried out or reduced to practice at the time of that publication.
- The Board of Patent Appeals and Interferences affirmed the examiner’s § 103 rejection, and applicants appealed.

## Issues

1. Whether the PTO properly found the claimed genetic engineering method and vectors obvious under 35 U.S.C. § 103 over the combination of the coinventors’ earlier publication and the Bahl reference.
2. How “obvious to try” and “reasonable expectation of success” apply in an experimental and sometimes unpredictable field such as biotechnology.

## Decision

- The Federal Circuit affirmed the Board’s decision sustaining the § 103 rejection.
- The court held the PTO established a prima facie case of obviousness and applicants failed to rebut it.
- The court concluded the prior art taught the key elements of the claimed gene-fusion approach and provided sufficient guidance that a skilled artisan would reasonably expect success through routine experimentation.
- The court rejected the argument that prior art must have actually reduced the claimed invention to practice to support an obviousness finding.

## Legal Principles

- An obviousness determination under § 103 requires both a reason to combine or modify the prior art and a reasonable expectation of success in achieving the claimed invention.
- “Obvious to try” is not a categorical basis for unpatentability; it depends on whether the prior art provides more than general research direction and instead points toward the claimed solution with a reasonable expectation of success.
- Prior art need not demonstrate actual performance or reduction to practice of the claimed invention; it is sufficient if it teaches the approach such that the remaining steps would be routine for a person of ordinary skill.
- Even in fields with uncertainty, obviousness may be found where the prior art provides concrete technical direction toward the claimed method and the required experimentation does not amount to inventive ingenuity.

## Conclusion

The Federal Circuit sustained the PTO’s § 103 rejection because the cited references, taken together, supplied motivation and enough technical teaching that a skilled artisan would reasonably expect to achieve the claimed gene-fusion vectors and protein-expression method through routine work, without requiring proof that the prior art had already performed the invention.


In re O’Farrell, 853 F.2d 894 (Fed. Cir. 1988)