On Nov. 16, 2021, Federal Circuit affirmed District court’s decision of invalidity and infringement.
Plaintiffs (Horizon) owns NDA for DUEXIS® (ibuprofen and famotidine) tablets, 800 mg / 26.6 mg. It is indicated for the relief of signs and symptoms of rheumatoid arthritis and osteoarthritis and to decrease the risk of developing upper gastrointestinal ulcers in patients who are taking ibuprofen for those indications. Defendant (Alkem) submitted ANDA on March 31, 2018 seeking USFDA approval to market generic version. Horizon sued Alkem in Delaware court for infringement of US 8,067,033 and US 8,067,451 patents. After a bench trial, the district court found that claims 1, 8, 11, and 14 of the ’033 patent were invalid for obviousness and not infringed, and that claims 1–3 and 8–10 of the ’451 patent were not infringed. You can read the detailed summary “here“.
During appeal, Horizon argued that district court committed legal error because the ’096 publication is not prior art to the ’033 patent. But, Federal Circuit found no error in the district court’s finding. The ’096 publication published on February 22, 2007, listing both Golombik and Tidmarsh as inventors. The ’033 patent has a priority date of November 30, 2007, listing Tidmarsh but not Golombik as an inventor. Horizon sought to correct the inventorship of the ’033 patent by adding Golombik as an inventor but District court denied. Federal Circuit said that the case laws are clear that inventing something in an earlier patent or patent application does not automatically make one an inventor of patents that incorporate the earlier invention. Court further said that there is also no corroborated collaboration with respect to the invention of the ’033 patent. Indeed, Golombik minimized his own involvement in its conception and admitted that Tidmarsh came up with the idea of separating the ibuprofen and famotidine into two portions.
With respect to the issue of obviousness, Horizon argued that the district court committed legal error in finding
that a person of ordinary skill in the art would have had a reasonable expectation of success to achieve the claimed
degree of stability in the ’033 patent. Federal Circuit, however, found no error and said that district court correctly found that a prior art reference (“the ’671 publication”) disclosed tablet-in-tablet separation methods, like those recited in the ’033 patent. The district court’s analysis is also supported by testimony from Alkem’s expert witness.
Horizon also appealed the district court’s noninfringement finding with respect to the ’033 patent. But Federal Circuit found the issue moot as asserted claims of the ’033 patent are invalid for obviousness.
Horizon also argued that the district court erred in construing “comprising” in the “barrier layer” term in the ’451 patent to mean “consisting essentially of,” and that the construction and subsequent finding of noninfringement
should be vacated. However, Horizon made no effort to show how the alleged error in interpreting “comprising” was prejudicial. Therefore, Horizon failed to establish harmful error warranting reversal. Moreover, the prosecution history of the ’451 patent supports the district court’s construction that Horizon unambiguously narrowed its claim scope to a specific barrier layer.