Allergan USA, Inc. v. MSN Labs. Priv. Ltd
Authored by: Jeremy J. Gustrowsky
In a significant decision for pharmaceutical patent holders, the Federal Circuit reversed a district court’s ruling that had invalidated several Allergan patents related to the drug eluxadoline, marketed as Viberzi®. The case centered on two main issues: whether Allergan’s earliest patent on eluxadoline (U.S. Patent No. 7,741,356) was invalid due to “obviousness-type double patenting” (ODP), and whether later formulation patents failed the “written description” requirement because they did not expressly require a glidant, an ingredient commonly used in tablet manufacturing.
On the double patenting issue, the Federal Circuit clarified that a first-filed, first-issued patent cannot be invalidated by a later-filed, later-issued, but earlier-expiring patent, even if the first patent received extra term due to Patent Term Adjustment (PTA). The court emphasized that the core purpose of ODP is to prevent unjust extensions of exclusivity for the same invention, not to penalize patentees for delays in prosecution that Congress specifically intended to remedy with PTA. In this case, because the ‘356 patent was the first to be filed and issued, it set the maximum exclusivity period for eluxadoline, and its extended term did not improperly prolong Allergan’s monopoly.
Regarding the written description requirement, the district court had found that Allergan’s later patents (U.S. Patent Nos. 11,007,179; 11,090,291; 11,160,792; and 11,311,516) were invalid because their claims did not require a glidant, yet all the detailed examples in the patents included one. The claims in Allergan’s patents covered pharmaceutical tablets with certain ingredients and amounts, but did not always require a glidant to be present—they sometimes described it as “optional” or omitted it entirely. However, the district court noted that every detailed example or embodiment in the patent’s written description actually included a glidant. Based on this, the court concluded that claims covering tablets without one were not adequately supported by the written description.
On appeal, the Federal Circuit disagreed with the district court’s interpretation. The appellate court pointed out that the patents’ specifications did, in fact, describe formulations where a glidant was “optional,” and that the original claims and language in the patents supported the idea that the inventors possessed both types of formulations—with and without a glidant. The court emphasized that the written description requirement does not demand that every possible variation be explicitly exemplified; it is enough if the specification reasonably conveys to a person skilled in the art that the inventors had possession of the claimed invention, including optional ingredients.
This decision is important because it clarifies that first-filed, first-issued patents with PTA are not at risk of “obviousness type” double patenting rejections for later-filed family members, and that written description can be satisfied even if some ingredients are not expressly required in every example. The ruling also serves as a reminder that patent disclosures should be read as a whole and from the perspective of a skilled artisan, not just by tallying up specific examples or the lack thereof.