## Facts

- Two Barcelona-based pharmaceutical-ingredient manufacturers held separate U.S. patents claiming processes related to preparing loratadine, the active ingredient in an antihistamine drug.
- Medichem owned U.S. Patent No. 6,084,100, which claimed a loratadine preparation process requiring reaction in an organic solvent in the presence of a tertiary amine with a low-valent titanium species generated by reducing titanium tetrachloride with zinc dust.
- Rolabo owned U.S. Patent No. 6,093,827, which claimed a process for preparing certain compounds (including relevant aza derivatives) by reacting a dibenzosuberone (or aza derivative) with an aliphatic ketone in the presence of low-valent titanium generated by zinc, using the transitional phrase “comprising.”
- Medichem sued under 35 U.S.C. § 291, alleging the patents interfered in fact because the claimed inventions were not patentably distinct.
- After a bench trial, the district court held there was no interference-in-fact, reasoning that Medichem’s tertiary-amine requirement made its claims nonobvious over Rolabo’s process and treating Rolabo’s claims as excluding tertiary amines.
- The district court also denied Rolabo’s request for attorney’s fees under 35 U.S.C. § 285, finding the case not exceptional.
- While the appeal was pending, the Board of Patent Appeals and Interferences declared an interference-in-fact between the same patents.

## Issues

1. Whether the district court misapplied the § 291 “two-way” interference-in-fact test by failing to determine, in both directions, whether each patent’s claims would anticipate or render obvious the other if treated as prior art.
2. Whether the district court erred by construing Rolabo’s “comprising” claims as excluding processes that use a tertiary amine.
3. Whether it was proper to deny attorney’s fees under § 285 while the interference and priority dispute remained unresolved.

## Decision

- The Federal Circuit vacated the judgment of no interference-in-fact.
- The court reversed the district court’s conclusion that Rolabo’s ’827 patent claims were neither anticipated nor obvious in light of Medichem’s ’100 patent claims.
- The case was remanded for further proceedings, including a proper two-way interference-in-fact analysis.
- The court held that any decision on Rolabo’s § 285 attorney’s fees request was premature given the remand and lack of a final prevailing party.

## Legal Principles

- In a § 291 action between issued patents, an interference-in-fact exists only if each party’s claims, treated as prior art, would anticipate or render obvious the other party’s claims (a two-way test that must be applied in both directions).
- The transitional term “comprising” is open-ended; a claim using “comprising” permits additional unrecited elements or steps and does not exclude them merely because they are not listed.
- A broader “comprising” claim can be anticipated by a narrower claim if the narrower claim’s embodiments fall within the scope of the broader claim.
- Attorney’s fees determinations under § 285 are generally premature where merits issues remain open and no party has finally prevailed.

## Conclusion

The Federal Circuit required a full, symmetrical two-way interference-in-fact analysis and rejected construing open-ended “comprising” claims as excluding unrecited components; it vacated the no-interference ruling, reversed related anticipation/obviousness conclusions, and remanded while deferring any § 285 fee decision.


Medichem, S.A. v. Rolabo, S.L., 353 F.3d 928 (Fed. Cir. 2003)