## Facts

- Patent applicants sought claims to isolated polynucleotides encoding a human natural killer cell receptor protein known as NAIL, including genus claims covering sequences encoding proteins that bind CD48 and meet specified sequence-identity criteria.
- The application disclosed amino acid and nucleotide sequences for NAIL regions and a full-length gene sequence, along with variants with similar binding properties.
- Prior art disclosed a natural killer cell receptor protein known as p38 and a monoclonal antibody specific to p38, and taught that p38’s DNA/protein sequences could be obtained using conventional methods.
- The prior art also provided a detailed, multi-step cloning protocol to isolate the receptor, though it did not provide the receptor’s nucleotide or amino acid sequence.
- A standard laboratory manual described routine molecular cloning techniques, including antibody-based cloning approaches.
- The Patent Office Board rejected the claims for (1) obviousness under 35 U.S.C. § 103(a) and (2) lack of written description under 35 U.S.C. § 112 ¶ 1.
- On appeal, the Federal Circuit accepted the Board’s factual finding that p38 and NAIL referred to the same protein.

## Issues

1. Whether claims to isolated DNA encoding a known protein were obvious under 35 U.S.C. § 103(a) where the prior art identified the protein, supplied a specific antibody and a cloning protocol, and taught routine methods for obtaining the gene.
2. Whether the application satisfied the written description requirement under 35 U.S.C. § 112 ¶ 1 (addressed only if necessary after resolving obviousness).

## Decision

- The Federal Circuit affirmed the Board’s rejection of all appealed claims as unpatentably obvious under § 103(a).
- The court applied a post-KSR obviousness analysis and approved an “obvious to try” rationale where the art provides a conventional path with a reasonable expectation of success.
- The court held it unnecessary to reach the Board’s written description rejection because obviousness was dispositive.

## Legal Principles

- A claim is obvious when the prior art would lead a person of ordinary skill to pursue the claimed invention with a reasonable expectation that conventional methodologies will succeed.
- In biotechnology, the fact that an exact DNA sequence is not known in advance does not preclude obviousness if the prior art teaches how to obtain the sequence using routine techniques and provides a concrete research path.
- “Obvious to try” supports a § 103 rejection when the prior art identifies a finite, predictable set of approaches and supplies tools and guidance that make success reasonably expected.
- Genus claims to closely related DNA variants do not become nonobvious merely because they require routine experimentation (e.g., conservative substitutions) once obtaining the underlying gene is itself obvious.

## Conclusion

The court upheld an obviousness rejection for DNA claims where prior art identified the target protein, provided an antibody and a cloning roadmap, and routine molecular biology methods supplied a reasonable expectation of successfully isolating the corresponding gene; written description was not reviewed because it did not affect the outcome.


In re Kubin, 561 F.3d 1351 (Fed. Cir. 2009)