In December 2008, the Delhi Patent Office rejected OSI Pharmaceuticals patent application no. IN/PCT/2002/507/DEL for polymorph B form of erlotinib hydrochloride in a pre-grant opposition proceeding filed by Cipla. Cipla challenged the application on the grounds of (1) prior publication, (2) publicly known and used in India, (3) obvious and lack in inventiveness, (4) not an invention/not patentable, and (5) failure to disclose information under section 8. In its [decision], the Patent Office found application lacking comparative data with respect to known substance to prove improvement in therapeutic and subsequently rejected claims for polymorph B of erlotinib hydrochloride under section 3(d) of the Patents Act, 1970. The decision was decided on December 15, 2008. Rejected application has corresponding patent in the United States listed with Orange Book. It is considered that Roche marketed Tarceva tablets contains polymorph B form of erlotinib hydrochloride.