Diabetes Drug Faces Patent Showdown at the Court of Appeals for the Federal Circuit
By: Katie Rubino
On February 16, 2021, the Court of Appeals for the Federal Circuit (CAFC) affirmed an appeal from the United States District Court for the District of New Jersey in Takeda Pharmaceutical Company LTD., Takeda Pharmaceuticals U.S.A., Inc., Takeda Pharmaceuticals America Inc., Takeda Ireland Limited, (“Takeda”) versus Torrent Pharmaceuticals LTD., Torrent Pharma Inc., (“Torrent”) and Indoco Remedies Ltd., (“Indoco”).
The case arose from an abbreviated new drug application (ANDA) dispute when Takeda alleged that defendants Torrent and Indoco would infringe on the claims of Takeda’s U.S. Patent 7,807,689 (’689 patent) entitled “Dipeptidyl Peptidase Inhibitors.” The ’689 patent is directed to the drug compound alogliptin, a uracil containing dipeptidyl peptidase inhibitor (DDP-4) sold under the brand names Nesina™, Kazano™, Incresync™, and Oseni™ for the treatment of Type II Diabetes Mellitus. DDP-4 inhibitors aid in lowering blood glucose levels by slowing down the inactivation and degradation of glucagon-like peptide 1 (GLP-1) in the intestines. DDP-4 inhibitors are widely prescribed by medical professionals because of their ability to reduce both fasting and postprandial blood glucose levels without causing weight gain.
During the bench trial at the district court, defendants Torrent and Indoco challenged the validity of the ’689 under both statutory obviousness as well as obvious-type double patenting. But the district court found against Torrent and Indoco, explaining that the defendants had failed to prove that the claims of the’689 patent were invalid for statutory obviousness or non-statutory obviousness-type double patenting. Torrent and Indoco then appealed to the CAFC, challenging several factual findings made by the district court.
As appellants, Torrent and Indoco first argued that the ’689 patent was invalid for obviousness type double patenting based on other references that mentioned that the administration of uracil lowers blood glucose in an animal model. However, the CAFC did not side with this argument, holding that the references did not demonstrate that uracil was known to specifically contain DPP-IV inhibitory activity as of the relevant priority date. Ultimately, the CAFC concluded that the district court did not err in finding that someone skilled in the art would be motivated to replace a pyrimidinone scaffold with a uracil scaffold and anticipate a reasonable expectation of success.
Torrent and Indoco subsequently argued that a person skilled in the art would have been motivated to replace a fluoro-olefin unit known in a pyrimidinone scaffold with an amide unit with a reasonable chance of success. But the CAFC also found this unpersuasive as Torrent and Indoco did not identify any prior art that would have taught this modification. Further, at trial, Torrent’s expert witness testified that he was unaware of any prior art demonstrating this modification.
Lastly, Torrent and Indoco argued that the district court had erred with respect to the level of ordinary skill in the art. Specifically, the appellants argued that the district court had ignored the parties’ dispute over whether an expert witness must specifically have experience developing DPP-IV inhibitors and/or Type II diabetes drugs, something Takeda’s expert did not have. However, the CAFC highlighted the fact that the district court had considered prior art having both perspectives, that of a person skilled in the art with and without DPP-IV inhibitor and/or Type II diabetes drugs experience.
In the end, the CAFC concluded that the district court did not err in upholding the validity of the ’689 patent. This case highlights that in the biochemical and pharmaceutical space, small changes and tweaks to a molecule can have significant changes on molecular properties, and thus significantly impact patent rights. Crafting a patent strategy that considers subsequent modifications can be helpful in warding off future patent challenges.