Pfizer Inc., FoldRx Pharmaceuticals, LLC, PF PRISM IMB B.V., and Wyeth LLC filed Pfizer Inc. et al. v. Zenara Pharma Private Limited, No. 1:26-cv-01402 (D. Del.), on October 29, 2026. The complaint says Zenara notified Pfizer by letter dated September 14, 2026 that it had submitted ANDA No. 221864 to the FDA seeking approval of generic tafamidis 61 mg before U.S. Patent 9,770,441 expires. According to the complaint, the notice letter reported a Paragraph IV certification asserting that the '441 patent is invalid, unenforceable, and/or will not be infringed by Zenara's ANDA product, and the suit was filed within forty-five days of receipt of that letter. The ANDA supplemental information entry on the docket lists September 15, 2026 as the date the patentees received notice and March 15, 2029 as the thirty month stay deadline.
The patent and the product
The complaint asserts one patent, U.S. Patent 9,770,441, titled "Crystalline solid forms of 6-carboxy-2-(3,5-dichlorophenyl)-benzoxazole," issued September 26, 2017, with 16 claims. The patent names Pfizer Inc. as applicant and assignee and lists Kevin Paul Girard, Andrew J. Jensen, and Kris Nicole Jones as inventors. The complaint says plaintiffs together own all substantial rights. It alleges that Vyndamax and its use are covered by one or more of claims 1-16 and that the patent is listed in the Orange Book for Vyndamax. FoldRx holds NDA No. 212161 for Vyndamax, which the complaint describes as approved for cardiomyopathy of wild-type or hereditary transthyretin-mediated amyloidosis in adults, with tafamidis as the active ingredient. The complaint describes NDA No. 212161 as covering tafamidis 61 mg capsules, while it describes Zenara's ANDA product as tafamidis 61 mg tablets.
The complaint quotes three claims. Claim 1 covers a crystalline form of 6-carboxy-2-(3,5-dichlorophenyl)-benzoxazole, the compound the complaint identifies as tafamidis, having an analytical parameter selected from a solid state NMR spectrum with 13C chemical shifts at 120.8 and 127.7 ppm (each plus or minus 0.2), a powder X-ray diffraction peak at 28.6 degrees 2-theta (plus or minus 0.2), or a Raman shift peak at 1292 cm-1 (plus or minus 2). Claim 15 covers a pharmaceutical composition containing the claim 1 crystalline form with at least one excipient. Claim 16 covers treating transthyretin amyloid disease in a mammal by administering a therapeutically effective amount of the claim 1 crystalline form.
The claims for relief
Count I alleges that submitting the ANDA was an act of infringement of the '441 patent under 35 U.S.C. § 271(e)(2)(A), and alleges, on information and belief, that Zenara will induce and contribute to infringement on approval. The complaint alleges, on information and belief, that Zenara's ANDA product contains a crystalline form of tafamidis meeting the claim 1 parameters. It says Zenara's notice letter purported to include an offer of confidential access subject to conditions the complaint calls unreasonably restrictive, that the parties did not agree on terms under which Pfizer could review, among other things, the Drug Master File referenced in the ANDA or relevant characterization data, and that Zenara refused to produce samples. Count II seeks a declaratory judgment of infringement. The prayer asks for a judgment of infringement under § 271(e)(2); an order that the effective date of any FDA approval of Zenara's ANDA product be no earlier than the patent's expiration, inclusive of any extensions and additional periods of exclusivity; a preliminary and permanent injunction; a declaratory judgment of infringement; a declaration that the case is exceptional, with attorneys' fees under 35 U.S.C. § 285; and costs. Zenara has not yet answered, and these are allegations the court has not decided.
Where the case stands
The docket shows the complaint, a Rule 7.1 disclosure statement identifying Pfizer Inc. as the corporate parent of the other plaintiffs, the patent report to the USPTO, and a summons issued to Zenara on October 30, 2026. A November 4, 2026 entry records a case assignment. For personal jurisdiction, the complaint alleges that Zenara regularly engages in patent litigation over FDA-approved branded drug products in this district and does not contest personal jurisdiction there, citing, among other cases, two District of Delaware cases in which Zenara is a defendant, Nos. 26-1154 and 26-857.
What to watch next
Watch for service on Zenara, its answer or a Rule 12 motion, and the assignment of a judge. Any case can end at any time, including by settlement or voluntary dismissal.