The Uncertain Landscape of Obviousness-Type Double Patenting
Life sciences companies have long relied on evergreening strategies to strengthen patent exclusivity around innovative therapies. Obviousness-type double patenting (ODP), which prevents patentees from effectively extending patent life through a second patent on a patentably indistinct invention, has always been a consideration in this calculus, but practitioners have generally operated with a clear understanding of its boundaries. That understanding is in flux and recent developments have only deepened the uncertainty.
In Ex parte Baurin (Appeal No. 2024-002920), the USPTO Director convened an Appeals Review Panel (ARP) to rehear the Board’s earlier reversal of the Examiner’s ODP rejections. The ARP reversed the Board and sustained the rejections but its reasoning raises as many questions as it answers. As an initial matter, the ARP concluded that the exception recognized in Allergan USA, Inc. v. MSN Laboratories Private Ltd. did not apply to the facts of Baurin, finding that none of Allergan’s three conditions was met. The ARP then relied on the anti-harassment rationale (the risk that separate owners of patents covering obvious variants could bring independent infringement suits) as an independent basis sufficient to sustain an ODP rejection, even where no term-extension concern was present. While this represents the Office’s current position, the ARP itself acknowledged that its analysis was compelled by existing Federal Circuit precedent and expressly invited the court to clarify whether ODP rejections can rest on the anti-harassment rationale alone.
It remains to be seen whether this interim position will hold. Ex parte Baumeister (Appeal No. 2026-000193), in which a different PTAB panel reached the opposite conclusion from the Board’s original Baurin decision and the same conclusion as the ARP, is now on appeal to the Federal Circuit as In re: Ablynx N.V. (Appeal No. 26-1333). The Federal Circuit’s resolution of Baumeister could yield binding precedent that either validates or rejects the anti-harassment rationale as a standalone basis for ODP and may fundamentally reshape how patent families are structured and prosecuted. Until that guidance arrives, the ARP has proposed a framework under which examiners would focus on comparing patent-term filing dates across families and actual filing dates within families, but has instructed USPTO personnel to continue following pre-Allergan practice under MPEP § 804 in the interim. Definitive guidance is not yet available, and practitioners should treat the current landscape as unsettled. Companies with large patent portfolios built through continuation strategies should evaluate their exposure and prepare for a range of outcomes as the resolution of these proceedings may alter the boundaries of patent family management.
Enablement and Written Description Requirements are Narrowing the Path Forward
The ODP uncertainty arrives alongside an increasingly demanding, but increasingly nuanced, standard for patent claims under 35 U.S.C. § 112. In the wake of the Supreme Court's decision in Amgen Inc. v. Sanofi, 598 U.S. 594 (2023), the Federal Circuit has applied rigorous scrutiny to whether broad genus claims in the life sciences are truly enabled across their full scope. Written description requirements have similarly tightened. For pharmaceutical and biotechnology companies, this means that broad claims covering antibodies, nucleic acid constructs, and chemical genera will likely face a narrower path to allowance than they did even a few years ago. Two recent decisions illustrate the boundaries the court is drawing.
In Teva Pharmaceuticals International GmbH v. Eli Lilly & Co., 172 F.4th 1367 (Fed. Cir. Apr. 16, 2026), the court reversed a judgment as a matter of laws (JMOL) of invalidity, holding that method-of-treatment claims directed to treating headaches using humanized anti-CGRP antagonist antibodies were both enabled and adequately described. The court distinguished Amgen on the grounds that the claims were directed to the therapeutic use of a well-known genus and not to the antibodies themselves. Because anti-CGRP antagonist antibodies were well known in the prior art, humanization was a routine procedure, and the specification disclosed that all humanized versions would treat headache, the court held that the relevant “research assignment” (i.e., whether the antibodies treat headache) was already completed in the specification, making any additional effort to identify and make every possible antibody “more akin to extra credit than a necessary research assignment.” Written description requirements have similarly tightened, though Teva again shows that the representativeness inquiry varies with the nature of the invention: where a well-known genus is used as part of a different invention, fewer disclosed species may suffice to satisfy the written description requirement.
By contrast, in Wyeth LLC v. AstraZeneca Pharmaceuticals LP, 2026 U.S. App. LEXIS 20004 (Fed. Cir. July 9, 2026), the court affirmed a JMOL of invalidity for lack of enablement of method-of-treatment claims directed to treating gefitinib/erlotinib-resistant non-small cell lung cancer using irreversible EGFR inhibitors. The specification disclosed only three compounds with in vitro data, provided no working examples of dosing in human patients, and offered only broad “general” and “projected” dosage ranges. Critically, unrebutted trial evidence showed that two of the three disclosed compounds exceeded maximum tolerated doses in humans across all disclosed ranges, and the specification left determination of a therapeutically effective unit dosage entirely to the skilled artisan’s judgment. The court held that a specification cannot rely solely on the knowledge of a skilled artisan to supply the novel aspects of an invention, and that in vitro data alone are insufficient to enable claims that contemplate daily administration to a patient.
The convergence of these trends creates a strategic squeeze. If an applicant pursues broad claims up front it risks invalidation under § 112 in the post-Amgen environment, where courts increasingly find that a limited number of working examples cannot enable a vast genus. As Teva and Wyeth illustrate, this risk is not confined to composition-of-matter claims‒method-of-treatment claims face the same scrutiny, and the outcome turns on the adequacy of the specification’s guidance across the full claimed scope rather than on claim type alone. But if an applicant instead pursues narrower, species-by-species claims across multiple applications, it risks triggering ODP rejections across its patent families. The result is a narrowing window within which to build layered patent protection. Life sciences companies should consider investing in more robust initial disclosures and, where possible, diversifying claim strategies across patent families.
The Supreme Court Clarifies Skinny-Label Protections for Generic Entry
On June 4, 2026, the U.S. Supreme Court issued a landmark decision in Hikma Pharmaceuticals USA Inc. v. Amarin Pharma, Inc. (No. 24-889) that significantly strengthens the practical value of the Hatch-Waxman Act's Section viii “carve-out” pathway for generic manufacturers. Under this framework, a generic company can avoid patent lawsuits if it “carves out” or excludes patented uses from its label—a so-called “skinny label.” The Federal Circuit previously allowed Amarin's induced-infringement claims to proceed based largely on Hikma's press releases, AB-rating references, and statements describing its product as a “generic version” of Vascepa®, despite Hikma having fully carved out Amarin's patented cardiovascular-risk-reduction indication. The Supreme Court reversed, holding that induced infringement requires affirmative, targeted conduct that actively encourages infringement. Ordinary distribution, lawful statements about generic equivalence, and FDA-required or industry-standard communications, without more, are not sufficient.
For branded life sciences companies, the decision raises the bar for enforcing method-of-use patents against skinny-label generic manufacturers. Complaints must now identify concrete statements or actions by the generic company that specifically point to the patented use such as sales scripts, physician-facing materials, payer presentations, or promotional content connecting the generic product to the protected indication. Brand name companies should reassess their patent prosecution strategies, use-code descriptions, and Orange Book listings to ensure patent claims map tightly to unavoidable portions of a generic label. For generic manufacturers, Hikma provides increased confidence in skinny-label launches but demands disciplined consistency: all communications—from FDA labels to investor materials to sales training—must align with the approved carve-out. The decision does not create a categorical safe harbor, but it meaningfully reduces the risk of litigation that previously made the Section viii pathway unreliable in practice.
This article is a part of the 2026 Life Sciences Industry Report. Click here to read the full newsletter.
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