In Echo of SCC’s Sildenafil Decision, the US CAFC Upholds Invalidation of Claims to a Family of Compounds for Non-enablement

In Echo of SCC’s Sildenafil Decision, the US CAFC Upholds Invalidation of Claims to a Family of Compounds for Non-enablement

Wyeth v. Abbot Labs (Fed. Cir. 2013)

Wyeth appealed from the U.S. District Court for the District of New Jersey’s grant of summary judgment that claims 1 and 2 of U.S. Patent No. 5,516,781 (’781 patent) and claim 1 of U.S. Patent No. 5,563,146 (’146 patent) are invalid for non-enablement.

The patents-in-suit relate to the use of the rapamycin family of compounds for the treatment and prevention of restenosis, which is the renarrowing of an artery. The claims recite a method of treating or preventing restenosis in a mammal, which comprises administering an antirestenosis effective amount of rapamycin to said mammal. While the patents use the term “rapamycin,” the parties agreed that the specification discloses only one rapamycin species called sirolimus.

The trial decision is affirmed. There is no genuine issue of material fact that the specification does not enable one of ordinary skill to practice the asserted claims without undue experimentation.

The Court agreed with Abbot and the trial court that practicing the full scope of the claims, measured at the time of filing, would require excessive experimentation. The scope of the claims at issue is broad. Under the trial court’s unchallenged construction of “rapamycin,” the invention is a new method of use of a known compound (sirolimus) and any other compounds that meet the construction’s structural and functional requirements. The Court agreed that the “specification’s guidance is limited to disclosures of the immunosuppressive and antirestenotic properties of sirolimus and assays to screen for those properties.” [7]

Practicing the full scope of the claims would require more than routine experimentation for two reasons: first, there are at least tens of thousands of potential rapamycin candidates. “The specification is silent about how to structurally modify sirolimus, let alone in a way that would preserve the recited utility.” [8] Second, “practicing the full scope of the claims would require synthesizing and screening each of at least tens of thousands of compounds,” which the Court held constitutes undue experimentation. [8]

Commentary

The CAFC’s decision echoes the Supreme Court’s sildenafil decision, and reemphasizes the importance of the patent bargain: in order for Wyeth to claim a monopoly over a large class of compounds, it had to provide sufficient disclosure to enable the skilled person to determine which compounds had utility and thereby to practice the full scope of the claims. The Court rejected Wyeth’s broad claims as enabling disclosure was lacking, and it was not possible for the skilled person to assess the utility of the compounds claimed without extensive and undue experimentation.