Opinions — Wednesday, July 1, 2026

The Federal Circuit affirmed the Trademark Trial and Appeal Board's refusal to register appellant Marini y Compañía, S.A.'s four MON AMI marks for edible pet treats in International Class 31 on likelihood-of-confusion grounds under § 2(d) of the Lanham Act. The Board had refused registration because the MON AMI marks were likely to be confused with a previously registered mark, AMÌ, also covering foodstuffs for animals in Class 31. Applying the DuPont multifactor test, the Board found that all but the sixth factor (number and nature of similar marks in use on similar goods, which was neutral) weighed in favor of likelihood of confusion. On appeal, Marini challenged the Board's factual findings under DuPont factor one—similarity of the marks in appearance, sound, connotation, and commercial impression—arguing that the Board improperly disregarded the grave accent mark over the "I" in AMÌ (which the registrant had stated had no Italian-to-English translation) and failed to give proper weight to the word "MON" in Marini's marks. The Federal Circuit held that substantial evidence supported the Board's factual findings and affirmed.

The case matters for its application of established principles governing how courts assess mark similarity when diacritical marks and foreign-language translations are at issue. The court reaffirmed that consumers may pronounce marks differently than the brand owner intends, citing In re Viterra Inc., and that accent marks do not necessarily prevent a finding of similarity where the underlying letters and sounds remain substantially alike. The Board declined to treat "AMI" as merely one component of the larger phrase "MON AMI," instead finding that "MON" reinforced rather than altered the meaning of "AMI" (friend), since the translation statement indicated "MON AMI" means "my friend" in French. The court further held that the Board permissibly assigned different weight to the "MON" element for rational reasons, citing QuikTrip West, Inc. v. Weigel Stores, Inc., and that where goods are identical, the degree of mark similarity required to support likelihood of confusion declines. The decision underscores the deference afforded to Board determinations on the relative dominance of mark elements and the limited utility of foreign-language translation arguments where the commercial impression remains similar.

The Federal Circuit affirmed the District of Delaware's grant of a preliminary injunction against Hetero Labs Limited for likely infringement of U.S. Patent No. 7,659,282, owned by Otsuka America Pharmaceutical and Avanir Pharmaceuticals, but vacated the district court's waiver of the bond requirement under Federal Rule of Civil Procedure 65(c). The case concerned the '282 patent's method claims for treating pseudobulbar affect using dextromethorphan and quinidine, specifically the construction of those terms in claim 1's weight-to-weight ratio limitation requiring "1:0.5 or less." Hetero argued that the ratio must be calculated using only the weight of the active moiety components (i.e., free base forms) even when the compounds are administered as salts, which would place both Hetero's generic and Otsuka's Nuedexta product outside the claim scope. The majority held that "dextromethorphan" and "quinidine" as used in the patent encompass both free base and salt forms, with the ratio calculated based on the weight of the compounds as administered. The court relied on claim differentiation (dependent claims 7 and 8 expressly recite salt forms), the specification's consistent use of abbreviated terms "DM" and "Q" to denote salt dosages in clinical studies, and the examiner's prosecution history statements treating the terms as including salts. Judge Dyk dissented in part on claim construction.

The decision clarifies that claim terms for chemical compounds are not automatically limited to free base forms when the specification and dependent claims explicitly contemplate salt formulations, and that dosage calculations track the form administered rather than requiring conversion to active moieties. This construction method protects patent holders from inadvertently excluding their own commercial products through overly narrow readings that privilege chemical nomenclature formalism over functional usage throughout the intrinsic record. The decision also reinforces that Third Circuit precedent strictly interprets Rule 65(c)'s bond requirement with limited exceptions, vacating the district court's equitable waiver despite Otsuka's likely success on infringement. Judge Dyk's partial dissent argued that the specification's chemical structure diagrams depicting free base forms and the need for conversion factors in clinical study tables indicated that the patentees distinguished between salt and free base weights, making Hetero's construction more consistent with how a person of ordinary skill would understand the weight-ratio limitation.