“Substantially Equivalent” Method of Obtaining Dissolution Profile Meets Written Description Requirement

In Nalpropion Pharmaceuticals v. Actavis Laboratories FL, Inc., No. 2018-1221 (Fed. Cir. Aug. 15, 2019), the Court addressed whether a particular claimed dissolution profile had the requisite written description support when the specification described dissolution data obtained using the USP Apparatus 1 Basket Method, whereas the specifically claimed dissolution profile was obtained using the USP Apparatus Paddle 2 Method.

In this Hatch-Waxman litigation, the proposed generic manufacturer argued that a particular asserted claim from one of the Orange Book listed patents lacked written description support because (i) the claim recited a specific dissolution profile that was collected using the USP Apparatus 2 Paddle Method, but (ii) the specification disclosed several tables of dissolution profile data collected using the USP Apparatus 1 Basket Method. The district court found credible the plaintiff’s expert’s statement that the claimed dissolution profile and the dissolution profile data in the specification in this particular case were “substantially equivalent." And in light of that substantial equivalence, the district court held the specification provided adequate written support.

The Federal Circuit affirmed the district court’s determination. It found no error to overturn the court’s reliance on the plaintiff’s expert testimony. Moreover, the Court stated that because the written description question in this particular case related to resultant dissolution parameters rather than an operative claim step, using substantial equivalence to show possession was acceptable.

Chief Judge Prost dissented, believing that the claim’s reliance on the USP Apparatus 2 Paddle Method was limiting; the Court’s precedent in Judge Prost’s view did not suggest “substantially equivalent” disclosure could provide written description support; and the district court erred in finding the specification included disclosure “substantially equivalent” to the specific claimed dissolution profile.