Routine High-Throughput Screening is Undue Experimentation, Federal Circuit Holds

Patent Pharmaceuticals Disclosure
Wyeth v. Abbott Labs By Kathleen McGuinness – Edited by Alex Shank [caption id="attachment_3442" align="alignleft" width="150"] Photo By: School of Natural Resources - CC BY 2.0[/caption] Wyeth v. Abbott Labs., Nos. 2012-1223, -1224, (Fed. Cir. June 26, 2013) Opinion On June 26, the U.S. Court of Appeals for the Federal Circuit upheld a lower court’s summary judgment of invalidity for nonenablement of certain patents relating to the use of rapamycin to treat restenosis, the renarrowing of an artery after the use of a balloon catheter. The court held that even “routine experimentation” to discover the working species of compounds within a claimed genus could constitute “undue experimentation,” given that chemical screening may require routine testing tens of thousands of compounds without any guidance from the patent. Patently-O briefly explains the court’s decision. Patent Docs provides a detailed critique of the holding. Bloomberg summarizes the history of the litigation. In 1992, Wyeth filed patents claiming a method of preventing restenosis through the administration of an “antirestenosis effective amount of rapamycin” as an immunosuppressant and antirestenotic agent. Wyeth at 3. Rapamycin refers to a class of compounds containing potentially millions of compounds, with tens of thousands having properties likely to make them candidates for pharmaceutical effectiveness. See id. at 6. However, Wyeth’s patent specification only disclosed a single rapamycin species, and only four other similar rapamycin compounds were known at the time of filing. Id. at 3–4. In a lawsuit between Wyeth and various medical stent companies, including Abbot Laboratories, the lower court held that Wyeth’s method claims were invalid for lack of enablement. The court concluded that it would require excessive and undue experimentation to determine which structural analogs of the disclosed rapamycin showed immunosuppressive and antirestenotic effects. Id. at 5–6. The Federal Circuit affirmed. While acknowledging that the necessary experiments would require only routine knowledge and assays, the court held that the process of assaying tens of thousands of possible compounds would reach the level of undue experimentation. Id. at 8. The court also noted the breadth of the claims and the fact that the specification was “silent” about which chemical modifications might produce viable alternatives to the disclosed rapamycin species. Id. Although the court reiterated its commitment to allowing “a considerable amount of experimentation . . .… as long as it is merely routine or the specification provides a reasonable amount of guidance,” it concluded that the scope of the necessary research to identify viable rapamycin species did not fall within the bounds of “merely routine.” Id. at 9 (internal quotations omitted) (quoting Johns Hopkins Univ. v. CellPro, Inc., 152 F.3d 1342, 1360–61). Wyeth conceded that “it would take technicians weeks to complete each of the[] assays” in the process of drug discovery. Id. at 10. Given the unpredictability of the art, the lack of guidance, and the time-intensive research that would be required,the court was unwilling to find that the necessary research constituted permissible “routine experimentation.” Id. The court did not comment on other equitable motivations for its holding, but Patent Docs suggests that it may have been influenced by the fact that Wyeth’s broad claim construction appeared designed to target competitors’ products that used rapamycin analogs not disclosed in the patent specification. Patently-O also notes the current push from policymakers to make enablement requirements more stringent. The holding in Wyeth may show, as both commenters suggest, a new Federal Circuit interest in tightening the requirements for patent disclosure and in requiring inventors to more unambiguously possess the inventions claimed.