On August 13, 2024, the Federal Circuit issued its decision in Allergan USA, Inc. v. MSN Laboratories Private Ltd., No. 24-1061,[1] which limits the scope of obviousness-type double patenting for patents in the same family. The Federal Circuit held that a first-filed, first-issued, later-expiring patent claim cannot be invalidated for obvious-type double patenting based on a later-filed, later-issued, earlier-expiring child patent when the patents share a common priority date.
Obviousness-type double patenting (ODP) is a judicially-created legal doctrine designed to prevent the improper extension of patent rights by prohibiting a patent applicant from obtaining multiple patents for inventions that are not patentably distinct from one other. Even after a patent is granted, a court can find that a patent is invalid for obviousness-type double patenting if it claims an invention that is obvious in view of an invention claimed in another patent with a common owner or inventor.
Sun Pharmaceutical Industries (Sun), working with MSN, submitted an Abbreviated New Drug Application (ANDA) in 2019 seeking FDA approval to market and sell a generic version of Viberzi®[2] (eluxadoline tablets). Allergan then sued Sun, alleging that Sun’s ANDA filing directly infringed U.S. Patent 7,741,356. The ’356 patent had over 1000 days of patent term adjustment (PTA), an extension of patent term due to patent office delay. Allergan also filed and was issued continuations (child patents) of the asserted patent. These child patents did not receive any PTA and thus had earlier expiration dates than the ’356 patent.
Sun argued that the later-expiring parent ’356 patent was invalid for obviousness-type double patenting over the child patents because its claims were not patentably distinct from the child patents and because it expires after the child patents. Based on its interpretation of Cellect,[3] another Federal Circuit case involving ODP from August 2023, the district court found the parent ’356 patent invalid for obviousness-type double patenting (ODP), concluding that the later expiration date from the patent term adjustment led to an unjust extension of patent term.
The Federal Circuit reversed, holding that a first-filed, first-issued, later-expiring claim cannot be invalidated by a later-filed, later-issued, earlier-expiring reference claim having a common priority date.
The Federal Circuit viewed this case and Cellect as dealing with different questions related to ODP. In this case, the parent ’356 patent was the first to be filed and issued, and defined the initial scope of exclusivity for the invention. The Federal Circuit noted the “crucial purpose” of ODP was to prevent an applicant from obtaining a second, later-expiring patent for a non-distinct invention, not to block a first patent simply because it had PTA. Here, the child patents derived from the same original application, but were filed later and were thus “second,” while the asserted ’356 patent was “first.” Thus, the child patents could not be used as ODP references invalidate the first filed ’356 patent.
The Federal Circuit concluded that the parent patent cannot be invalidated by the child patents merely because the parent patent had a longer term due to patent term adjustment. Invalidating earlier-filed patents in this scenario would undermine the purpose of patent term adjustment, which is to compensate for delays in patent prosecution, and would create an unjust scenario where a patent owner would lose the benefit of a duly awarded extension.
This decision provides relief to many patent owners who had viewed the In re Cellect decision as creating potential patent invalidation problems due to ODP when there was patent term adjustment.
Editor: Brenden S. Gingrich, Ph.D.
