From Cabozantinib to Zanzalintinib: Obvious Chemical Modifications as a New Frontier in Product Hopping

Exelixis’ development of zanzalintinib, a chemically modified successor to its blockbuster drug cabozantinib (Cabometyx, Cometriq), illustrates how obvious covalent changes to an active ingredient can secure a new composition-of-matter patent and extend market exclusivity ahead of a patent cliff. Lead compound analysis indicates zanzalintinib was legally obvious over cabozantinib, pointing to a need for stronger USPTO-FDA coordination in patent examination to better capture this novel form of product hopping.