Merck's JANUVIA Crystalline Monohydrate DHP Salt Patent Found Valid

In a patent infringement action brought under subsection 6(1) of the Patented Medicines (Notice of Compliance) Regulations, in relation to sitagliptin phosphate monohydrate (Merck's JANUVIA), Justice Furlanetto of the Federal Court found Canadian Patent No. 2,529,400 (the 400 Patent) to be valid and granted a declaration of infringement: Merck Sharp & Dohme Corp v Pharmascience Inc, 2022 FC 417.

The 400 Patent

The 400 Patent is directed to the dihydrogen phosphate (DHP) salt of sitagliptin and its crystalline monohydrate form, a process for its preparation, its formulation as a pharmaceutical composition, and its use to treat diseases affected by the inhibition of dipeptidyl peptidase-4 (DPP-4; an enzyme that degrades one of the peptides that stimulates the secretion of insulin), such as type 2 diabetes. The 400 Patent asserts that the crystalline DHP salt of sitagliptin has pharmaceutical advantages over the sitagliptin free base and hydrochloride salt