The US Food and Drug Administration has issued a green light for Astellas’ application to market Cresemba (isavuconazonium sulfate) for two rare but life-threatening fungal infections, triggering a 30 million Swiss Francs milestone payment to development partner Basilea.

Aspergillosis is a fungal infection caused by Aspergillus species, and mucormycosis is caused by the Mucorales fungi. Both infections mostly occur in people with weakened immune systems.

Approval of once-daily treatment, either in intravenous or pill form, came on the back of three Phase III clinical trials including the 516-patient Secure study pitting Cresemba against another antifungal agent called voriconazole in treating invasive aspergillosis or other filamentous fungi.

This showed that the agent was non-inferior to voriconazole in efficacy. On the safety side, the FDA noted that data show treatment may cause serious side effects such as liver problems, infusion reactions and severe allergic and skin reactions.

Cresemba is the sixth approved antibacterial or antifungal drug product designated as a Qualified Infectious Disease Product, under which it was given a priority review and an additional five years of marketing exclusivity. It also carries orphan drug designations for both type of infections.