Opinions — Monday, February 23, 2026

In Prime Time Toys LLC v. Spin Master, Inc., the Federal Circuit dismissed consolidated appeals in Nos. 2026-1236, 2026-1238, and 2026-1239 from three Patent Trial and Appeal Board inter partes review proceedings under Fed. R. App. P. 42(b) based on the parties' agreement, with each side to bear its own costs.

The Federal Circuit affirmed the district court's judgment following a bench trial that Sandoz Inc. infringed U.S. Patent No. 9,867,919, assigned to Duke University and licensed to Allergan Sales, LLC, which claims bimatoprost formulations for treating glaucoma and ocular hypertension. The court held that Sandoz's proposed generic product literally infringed the asserted claims and that those claims were not invalid for obviousness. The central legal questions concerned claim construction of concentration ranges and particle size limitations, and whether substantial evidence supported the district court's factual findings on infringement and obviousness. The court applied the clear error standard to the district court's findings that Sandoz's formulation fell within the claimed parameters, resolving a dispute between competing expert testimony regarding particle size measurements where Sandoz's expert testified to a mean of 4,230 nanometers and Allergan's expert testified to 1,620 nanometers.

The decision reinforces deference to district court credibility determinations in bench trials involving conflicting expert testimony on pharmaceutical formulation parameters, particularly where measurement methodologies differ. The affirmance signals that generics seeking to design around patented concentration and particle size ranges face a demanding burden when district courts credit patentee expert evidence on formulation characteristics, even where the parties' experts reach substantially different quantitative conclusions using different analytical techniques. The opinion provides practitioners with guidance on presenting and challenging expert testimony regarding bimatoprost formulations specifically, and more broadly illustrates how Federal Circuit review of bench trial findings operates in Hatch-Waxman cases where physical and chemical properties must be proven through dueling expert methodologies rather than direct documentary evidence.

The Federal Circuit reversed-in-part the Patent Trial and Appeal Board's decision in an inter partes review brought by Apple Inc. against Smart Mobile Technologies LLC concerning the '936 and '739 patents. The court held that claim 1 of the '936 patent was unpatentable based on issue preclusion, reversing the Board's contrary determination, and remanded for consideration of dependent claims that relied on claim 1's validity.

The court's application of issue preclusion turned on whether Smart Mobile Technologies had a full and fair opportunity to litigate claim construction and obviousness arguments in the prior IPR proceeding. The court found all elements satisfied, emphasizing that the patent owner had addressed the relevant claim limitations and prior art combinations in its earlier Patent Owner Response, including proposed constructions for "dynamic" as used in multiple claim limitations and arguments addressing the same references Apple relied upon. The Board's error in declining to apply issue preclusion required reversal as to the independent claim and remand for reconsideration of claims whose patentability depended entirely on that flawed determination.

The Federal Circuit reversed the district court's judgment of invalidity but affirmed dismissal of breach-of-contract claims in NimbeLink Corp. v. Digi International Inc. NimbeLink owns patents covering embedded cellular modems and sued Digi for infringement and breach of two non-disclosure agreements executed during acquisition discussions. The district court held the preamble term "space-efficient cellular modem device" was a limiting but indefinite claim term under 35 U.S.C. § 112(b), rendering all asserted claims invalid.

The Federal Circuit applied Catalina Marketing and related precedent to hold the preamble term "space-efficient" non-limiting, concluding it merely extolled benefits of structural features already recited in the claim body rather than adding essential structure. The court distinguished cases where preambles supply necessary antecedent basis, finding that while "cellular modem device" provided such basis for dependent claims, "space-efficient" did not, and that the structural completeness of the claim body meant deleting the modifier would not affect the claimed invention. The court also found no prosecution history disclaimer, as the examiner's allowance rationale referenced "specific circuit structure" and "arrangement" without clearly relying on the preamble's "space-efficient" language to distinguish prior art.