Osimertinib mesylate is a methanesulfonate (mesylate) salt prepared from equimolar amounts of osimertinib and methanesulfonic acid. Osimertinib is indicated as a first line treatment of metastatic non-small-cell lung cancer with specific mutations. It demonstrated impressive results in phase IV clinical studies. Here at Teva api, the way we produce the osimertinib API is entirely green, as our ecofriendly and efficient process involves minimal isolation of intermediates. Another huge plus is that we have good control of impurities, especially genotoxic ones.