Leerink analyst Paul Matteis notes that Alnylam has announced that it has suspended Fitusiran dosing due to a fatal thrombotic event in a patient with hemophilia A without inhibitors. The analyst notes that blood clot risk was always highlighted as a theoretical concern in discussions with investors who were more skeptical on the program. The company aims to resume dosing as soon as possible upon agreement with global regulatory authorities and with appropriate protocol amendments in place for enhanced safety monitoring, he adds. However, Matteis believes that the commercial opportunity may now be limited given the risk-averse nature of the hemophilia patient population. He reiterates a Market Perform on the shares.