The initial process development focused on addressing the most critical issues to enable the production of 1 kg of MRTX0902 fumarate salt to satisfy the initial program demand. A more indepth development work and de novo synthesis will be presented later in this manuscript. The drug discovery approach was used to manufacture 6 kilograms of 1,7-dichloro-4methylpyrido pyridazine 6 while the final steps were modified and improved using the knowledge acquired during the initial steps of process development, see Scheme 2.