Addressing infringement under the doctrine of equivalents and obviousness issues, the US Court of Appeals for the Federal Circuit affirmed the district court’s ruling barring approval of a generic version of Finacea^® gel until November 2018. Intendis GmbH, et al. v. Glenmark Pharms. Inc., USA, et al., Case No. 15-1902 (Fed. Cir., May 16, 2016) (Moore, J).

Intendis is the assignee of a patent directed to compositions containing azelaic acid, which is listed in the Orange Book as covering Finacea^® gel, a treatment for rosacea. Glenmark developed a generic version of Finacea^® gel and filed an Abbreviated New Drug Application (ANDA) with the US Food and Drug Administration (FDA), asserting that the Intendis patent was invalid and that Glenmark’s generic version did not infringe. Following a trial, the district court found that Glenmark’s ANDA product infringed Intendis’s patent under the doctrine of equivalents, and that the asserted claims were not obvious because there was no motivation to combine the proposed prior art references and no reasonable expectation of success in making such a combination, and because the unexpected results and commercial success weighed in favor of non-obviousness. Glenmark appealed both rulings to the Federal Circuit.

With respect to infringement under the doctrine of equivalents, the Federal Circuit found that the only question in dispute was whether Glenmark’s isopropyl myristate had the same function as the combination of triglyceride and lecithin in the patent, and, in this case, there was sufficient evidence for the district court to conclude that it did. The panel noted that Glenmark had repeatedly asserted to the FDA both that isopropyl myristate acted as a penetration enhancer in its ANDA product, and that lecithin and triglyceride served the same purpose in Finacea^® gel. The panel also rejected Glenmark’s argument that the doctrine of equivalents could not apply because the specification did not explicitly call out this function, stating that “[w]e have never held that a patent must spell out an element’s function, way and result in order for the doctrine of equivalents to apply to that element.” The court further rejected the argument that a finding of equivalence would encompass the prior art, finding that Glenmark’s proposed hypothetical claim covering all penetration enhancers was too broad and that prosecution history estoppel did not prevent Intendis from asserting equivalence with respect to a lecithin-free composition.

Finally, the Federal Circuit affirmed the non-obviousness finding, ruling that although one of skill in the art would have been motivated to pursue an azelaic acid compound based on the prior art, one would not have been motivated to use the combination of triglyceride and lecithin claimed in the patent as excipients.