Addressing the validity of patents involved in a Hatch-Waxman litigation, the US Court of Appeals for the Federal Circuit held that claims were invalid for lack of an adequate written description because the specification failed to explain the efficacy of the claimed drug. Nuvo Pharmaceuticals v. Dr. Reddy’s Laboratories Inc. et al., Case Nos. 17-2473, -2481, -2484, -2486, -2489, -2491, -2492, -2493 (Fed. Cir. May 15, 2019) (Clevenger, J).

Nuvo owns two patents that claim an uncoated proton pump inhibitor (PPI) effective to raise the gastric pH to at least 3.5. Nuvo filed a patent infringement complaint against Dr. Reddy’s, Mylan and Lupin, alleging that the generic drug manufacturers infringed the two patents based on the filing of an abbreviated new drug application. The generic drug manufactures defended, arguing that the patents were invalid. The district court rejected the invalidity arguments, finding that ordinarily skilled artisans would not have expected uncoated PPIs to be effective. The generic drug manufacturers appealed.

On appeal, the generic drug manufacturers argued that the district court clearly erred when it concluded that the claimed effectiveness of un-coated PPI in the asserted patents was supported by written description, because ordinarily skilled artisans would not have expected it to work and the specification provided no experimental data or analytical reasoning showing that the inventor possessed an effective uncoated PPI.

Agreeing with the generic drug manufacturers, the Federal Circuit reversed the district court, finding that the specification lacked “information regarding the efficacy of uncoated PPIs,” even though it provided dosage amounts of un-coated PPI and disclosed the use of uncoated PPI in a drug formulation. Acknowledging that the law requires neither experimental data demonstrating effectiveness nor a theory or explanation of how or why a claimed composition will be effective, the Court nevertheless found that the patents “never discuss[] or explain[] its efficacy” and a person of ordinary skill in the art would not have known or understood that uncoated PPI was effective. In making this finding, the Court expressly rejected the notion that the appearance of mere indistinct words in a specification or a claim, even an original claim, necessarily satisfies written description, because it may not put others on notice of the scope of the claimed invention or demonstrate possession of that invention. The Court also recognized that the enablement requirement, which requires the specification to teach those skilled in the art how to make and use the claimed invention without undue experimentation, is separate and distinct from the written description requirement, and that even if an invention is enabled (as was the case here), that does not mean it is adequately described, and vice versa.

Practice Note: As noted by the Federal Circuit, the purpose of the written description requirement is broader than to merely explain how to “make and use” the invention. The focus of the written description requirement is instead on whether the specification notifies the public about the boundaries and scope of the claimed invention and shows that the inventor possessed all the aspects of the claimed invention. Successful defendants can strategically maneuver a §102/§112 squeeze forcing the patentee to make admissions about the unpredictability of the invention, ultimately using those same admissions to demonstrate a lack of a written description. While not legally required, patentees may consider mitigating this threat during prosecution by including experimental data, or some reason, theory or explanation that is more than a mere recitation of the claim language, as to how and why the claimed invention is possessed by the inventor.