Process Developmenttoward the Continuous Manufacturingof Baloxavir Marboxil

We report the initial studies toward the continuous processing of Baloxavir Marboxil, the active pharmaceutical ingredient (API) of Roche’s commercial product Xofluza. The motivation behind this effort is to transition to integrated continuous manufacturing (ICM) as a platform to create an agile and on-demand supply chain capability for a drug that has highly variable market demand. The work described herein includes an improved late-stage synthetic route to Baloxavir Marboxil that (1) reduced a four-step synthesis down to two steps, (2) identified key diastereomeric crystallization conditions to reach required material specifications, and (3) removed the use of <i>N,N</i>-dimethylacetamide in exchange for a more environmentally benign solvent mixture of acetonitrile and water. After a full revision of the two-step synthetic route in batch mode, key unit operations were translated to continuous mode to evaluate their performance. Collectively, this work eliminated 16 unit operations, significantly simplified the process, and is projected to reduce the lead time from 12 months to several days using ICM.