International Nonproprietary Name
In the early 1990s a number of derivatives of "N"-phenyl-2-pyrimidineamine were synthesized by scientists at Ciba-Geigy (now part of Novartis), one compound of which was CGP 57148 in free base form (later given the International Nonproprietary Name ‘imatinib’ by the World Health Organization (WHO)). A Swiss patent application was filed on 3 April 1992, which was then filed in the EU, the US, and other countries in March and April 1993 and in 1996 United States and European patent offices granted a patent to Novartis claiming imatinib and its derivatives, including salts thereof (but not mentioning mesylate). The patent does not specify any crystal forms of the compounds or discuss their relative advantages and disadvantages.