## Facts

- Par owned two patents claiming stable flocculated suspensions of megestrol acetate and methods of making them.
- Roxane, a generic manufacturer, was accused of infringing by marketing a megestrol acetate suspension product.
- After claim construction, the district court construed “stable flocculated suspension” to require an open-network aggregate producing a loosely packed, scaffold-like sediment rather than a solid cake.
- Par drafted claims broad enough to cover hundreds of surfactants and combinations, based on its view that stable flocculated suspensions could be made using many surfactants and wetting agents.
- The patents disclosed only three working examples demonstrating successful formulations using seven surfactants, with limited disclosure beyond a previously known formulation.
- The specifications stated that surfactants must be chosen carefully and used within a “critical concentration range,” warning that minor changes could affect formulation properties.
- Evidence (including inventor testimony) indicated that whether a given surfactant and concentration would produce a stable flocculated suspension could not be predicted in advance and required experimentation.
- The district court granted summary judgment that the asserted claims were invalid for lack of enablement under 35 U.S.C. § 112, ¶ 1.

## Issues

1. Whether the patents enabled the full scope of the asserted broad claims—covering hundreds of surfactants and concentration ranges—without undue experimentation under 35 U.S.C. § 112, ¶ 1.
2. Whether summary judgment of invalidity for lack of enablement was proper on this record.

## Decision

- The Federal Circuit affirmed summary judgment that the asserted claims were invalid for lack of enablement.
- Applying the undue-experimentation framework (including the In re Wands factors), the court found a stark mismatch between the claims’ breadth and the limited guidance and examples in the specifications.
- The court treated the patents’ own statements about “critical” concentration ranges and sensitivity to minor changes as evidence of unpredictability inconsistent with enabling a broad genus.
- Inventor testimony that successful formulations required “actual experimentation” supported the conclusion that practicing the full claim scope would require extensive trial and error.
- Par’s proof that it had made stable suspensions using seven surfactants was deemed insufficient to create a genuine dispute of material fact as to enablement across the full claimed range.

## Legal Principles

- Enablement requires that the specification teach a person of ordinary skill to make and use the full scope of the claimed invention without undue experimentation.
- In assessing undue experimentation, courts consider factors such as claim breadth, predictability of the art, the amount of guidance and working examples, and the quantity of experimentation needed.
- Broad claims in an unpredictable chemical/formulation field may be invalid where the disclosure provides only limited exemplification and does not supply sufficient guidance to practice the full genus.
- Summary judgment on enablement is appropriate when, viewing intrinsic and extrinsic evidence, no reasonable fact-finder could conclude the full claim scope is enabled.

## Conclusion

The Federal Circuit upheld invalidity for lack of enablement because the patents claimed an exceptionally broad range of surfactant-based megestrol acetate suspensions while providing minimal examples and acknowledging sensitivity to small compositional changes, making undue experimentation necessary to practice the full scope.


Pharmaceutical Resources, Inc. v. Roxane Laboratories, Inc., 253 F. App’x 26 (Fed. Cir. 2007)