Insmed Incorporated announced that the US Food and Drug Administration (FDA) has accepted its Supplemental New Drug Application (sNDA) for review of Arikayce (amikacin liposome inhalation suspension) for the treatment of Mycobacterium Avium Complex (MAC) lung disease as part of a combination antibacterial drug regimen.

The FDA has granted Priority Review to the application and set a target action date of January 28, 2027, under the Prescription Drug User Fee Act (PDUFA). Priority Review is granted to applications for medicines that, if approved, have the potential to provide significant improvements in the safety or effectiveness of treatments for serious conditions.

The sNDA seeks full approval for Arikayce based on results from the Phase 3b ENCORE study, which was conducted to fulfil the post-marketing requirement associated with the product’s accelerated approval. The study met its primary endpoint and multiplicity-controlled secondary culture conversion endpoints, with Arikayce plus multidrug therapy demonstrating statistically significant improvements in respiratory symptoms and culture conversion compared with multidrug therapy alone.

“MAC lung disease is progressive — the longer the infection persists, the greater the damage to lung tissue and the harder it becomes to treat,” said Martina Flammer, Chief Medical Officer, Insmed. She added that, if approved, Arikayce could potentially reach patients earlier in their disease course, including those newly diagnosed or experiencing recurrent infections.

Arikayce received accelerated approval from the FDA in 2018 for refractory MAC lung disease. It was the first product approved under the Limited Population Pathway for Antibacterial and Antifungal Drugs (LPAD), established under the 21st Century Cures Act to support the development of antibacterial therapies for serious or life-threatening infections affecting patients with unmet medical needs.

The ENCORE study was a randomised, double-blind, placebo-controlled Phase 3b trial evaluating the efficacy and safety of Arikayce plus multidrug therapy in patients with a new occurrence of MAC lung infection who had not previously received antibiotics. The study enrolled 425 patients across 177 sites globally, including patients experiencing their first MAC infection (82.4 percent) and those experiencing their second or third infection (17.6 percent).

Patients were randomised 1:1 to receive either once-daily Arikayce plus multidrug therapy consisting of azithromycin 250 mg and ethambutol 15 mg/kg, or placebo plus the same multidrug therapy. The treatment period lasted 12 months, followed by three months off treatment to assess the durability of culture conversion.

The primary endpoint was the change from baseline in Respiratory Symptom Score at Month 13. ENCORE met this endpoint as well as its multiplicity-controlled secondary culture conversion endpoints. Patients receiving Arikayce achieved earlier, greater and more durable culture conversion compared with those receiving comparator therapy. The safety profile was consistent with the known safety profile of Arikayce, with no new safety signals identified.

Insmed also plans to discuss the ENCORE data with Japan’s Pharmaceuticals and Medical Devices Agency (PMDA) in the fourth quarter of 2026 to support potential label expansion in Japan.

Arikayce is approved in the US as Arikayce (amikacin liposome inhalation suspension), in Europe as Arikayce Liposomal 590 mg Nebuliser Dispersion and in Japan as Arikayce inhalation 590 mg. It is a once-daily inhaled formulation of amikacin delivered directly to the lungs using Insmed’s proprietary Pulmovance liposomal technology.