Sunitinib is a drug for treating cancers in the stomach,
intestine, kidney and pancreas, marketed by Pfizer under the name
Sutent®. The CN patent directed to sunitinib basic chemical
structure has its full termed expired in Feb 2021. There is a
crystal form patent directed to sunitinib malate, the chemical
entity in the actual drug, with full term expiry in Aug 2022.
However, this sunitinib malate crystal form I (crystal form I)
patent CN100439360C ('360) has been invalidated in Apr 2021,
opening the door to generics of sunitinib earlier in China.
The corresponding EP1419151B of '360 was maintained by the
EPO after opposition with post-filing data showing that the free
base crystal of sunitinib were small with poor filterability, while
cystal form I has good filterability with full compatibility with
commercial manufacturing processes.
