## Facts

- Hybritech owned U.S. Patent No. 4,376,110, claiming methods and diagnostic kits for two-site “sandwich” immunometric assays using monoclonal antibodies to detect antigens in biological fluids.
- The patented format used a solid-phase monoclonal antibody to capture antigen and a second labeled monoclonal antibody to bind a different epitope, creating a detectable “sandwich.”
- The application for the patent was filed on August 4, 1980.
- Monoclonal Antibodies, Inc. was accused of infringing all 29 claims of the patent.
- After a bench trial, the district court held all claims invalid for anticipation under 35 U.S.C. § 102(g), obviousness under § 103, and multiple defects under § 112 (enablement, best mode, and indefiniteness), relying heavily on asserted earlier work by other researchers.
- Hybritech appealed the invalidity judgment to the Federal Circuit.

## Issues

1. Whether asserted third-party work constituted prior invention that anticipated the claims under 35 U.S.C. § 102(g), including requirements of conception, diligence, and corroboration.
2. Whether the claimed monoclonal-antibody sandwich immunoassays and kits were obvious under 35 U.S.C. § 103 when the invention is assessed as a whole, including consideration of objective indicia of nonobviousness.
3. Whether the claims and specification failed § 112 due to lack of enablement, failure to disclose best mode, or indefiniteness (including terminology addressing antibody “affinity”).

## Decision

- The Federal Circuit reversed the district court’s judgment of invalidity and remanded.
- The court held the § 102(g) anticipation finding was clearly erroneous because the evidence did not establish qualifying prior invention defeating Hybritech’s priority.
- The court held Monoclonal did not carry its burden to prove obviousness by clear and convincing evidence, particularly given errors in the trial court’s approach and its treatment of objective evidence.
- The court held the patent satisfied § 112: the disclosure enabled the claimed assays without undue experimentation, no best mode violation was shown, and the claims were sufficiently definite to inform skilled artisans of their scope.

## Legal Principles

- Under § 102(g), prior invention requires a definite and permanent conception of the complete operative invention plus appropriate diligence toward reduction to practice; inventor testimony on these points generally requires corroboration.
- Laboratory notebooks and related records can corroborate inventive activity, including when witnessing occurs after the fact, depending on the evidentiary showing.
- Obviousness under § 103 must assess the claimed invention as a whole; analysis that dissects elements and then recombines them with hindsight is legally erroneous.
- Objective indicia of nonobviousness (e.g., commercial success, long-felt need, failure of others, unexpected results) are part of the obviousness analysis and must be weighed before reaching an obviousness conclusion.
- Invalidity defenses must overcome the presumption of validity with clear and convincing evidence.
- For enablement, a specification need not teach what is already well known to skilled artisans; the question is whether the disclosure enables practice of the claimed invention without undue experimentation.
- Best mode focuses on the inventor’s subjectively preferred mode at the filing date and requires proof of concealment or omission of that mode.
- Definiteness is satisfied when claim language reasonably informs skilled artisans of claim scope, even if measurements (such as affinity) may vary in practice.

## Conclusion

The Federal Circuit restored the patent’s presumptive validity by rejecting the district court’s § 102(g), § 103, and § 112 invalidity holdings, emphasizing whole-claim obviousness analysis with mandatory consideration of objective indicia, and clarifying that patents need not restate well-known techniques to satisfy enablement.


Hybritech Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367 (Fed. Cir. 1986)