Apotex's Ruxolitinib Formulation Change
Apotex developed an Abbreviated New Drug Application (ANDA) for a generic version of Incyte's Jakafi (ruxolitinib phosphate), but altered the drug product by switching from a tablet containing povidone (polyvinylpyrrolidone, PVP) as the binder to one using copovidone (a copolymer of 1-vinyl-2-pyrrolidinone and vinyl acetate). This change addressed stability issues with povidone in the original formulation, as copovidone provides better compatibility with ruxolitinib's phosphate salt.[1][2]
Why the Change Triggered Patent Litigation
Incyte holds U.S. Patent No. 10,696,641 covering pharmaceutical compositions of ruxolitinib with copovidone as the binder, specifically excluding formulations with only povidone. Apotex's substitution was deemed an infringement because it directly adopted this patented excipient combination. The Delaware District Court ruled in favor of Incyte in 2023, finding the patent valid and infringed; Apotex's appeal is pending at the Federal Circuit.[1][3]
Impact on Generic Entry Timeline
The patent, listed in the FDA's Orange Book for Jakafi, expires in 2036 (with pediatric exclusivity to 2037). Apotex's Paragraph IV challenge under Hatch-Waxman delayed FDA approval pending litigation. No generics are approved yet; other challengers like MSN and Sandoz face similar suits.[2][4]
Chemical and Stability Rationale
Ruxolitinib (formula C17H18N6, as phosphate salt) is prone to degradation in acidic environments. Povidone can exacerbate this via interactions forming degradants like ruxolitinib dimer. Copovidone's vinyl acetate component reduces such reactivity, improving shelf-life without altering the active ingredient's structure. Apotex's bioequivalence data confirmed comparable pharmacokinetics.[1][5]
Sources:
[1] DrugPatentWatch.com - Jakafi Patents
[2] Incyte Corp. v. Apotex Inc., Del. 2023
[3] Finnegan IP Blog - Incyte v. Apotex
[4] FDA Orange Book - Jakafi Entries
[5] EMA Jakavi Assessment (formulation notes)