Learning the limits of limited use
How FDA’s LPAD pathway tipped the scales for Insmed’s Arikayce amikacin
While it’s too soon to tell if FDA’s limited-use pathway for anti-infectives will boost development in the underserved field, the pathway’s first approval has helped clarify the amount of uncertainty the agency is willing to accept.
On Sept. 28, FDA granted accelerated approval to Insmed Inc.’s Arikayce amikacin, an inhaled liposome suspension, to treat lung infections caused by Mycobacterium avium complex (MAC). The approval is restricted to adults who do not respond to standard of care and therefore have few or no treatment options.
FDA’s Limited Population Pathway for Antibacterial and Antifungal Drugs (LPAD) was created in 2016 under the 21st Century Cures Act to streamline such reviews. It allows the agency to base decisions on relatively small data sets when the targeted subpopulation has serious or life-threatening disease.
Before Arikayce, no products were approved to treat nontuberculous mycobacterial (NTM) infections such as those caused by MAC, which can lead to progressive irreversible lung damage and death. First-line therapy is typically a triple combination of a macrolide antibiotic, a rifamycin antibiotic and ethambutol, and is estimated to cure no more than 65% of the infections.
FDA would have had the