The FDA has granted Priority Review to Insmed's supplemental new drug application (sNDA) for amikacin liposome inhalation suspension (ARIKAYCE) seeking full approval for newly diagnosed and recurrently infected Mycobacterium avium complex (MAC) lung disease, the company announced September 21, 2026, with a PDUFA target action date of January 28, 2027.¹
Amikacin liposome inhalation suspension is currently approved only under the Limited Population Pathway for Antibacterial and Antifungal Drugs (LPAD) for refractory MAC lung disease in patients who have failed at least 6 months of multidrug therapy without achieving negative sputum culture conversion.¹ The sNDA, if approved, would expand the label to frontline use as part of combination antibacterial therapy, moving amikacin liposome inhalation suspension from a refractory-disease option to a treatment-naive one.¹ Amikacin liposome inhalation suspension was the first product approved under the LPAD pathway, established by the 21st Century Cures Act, with its 2018 accelerated approval conditioned on a postmarketing confirmatory trial.¹
“MAC lung disease is progressive. The longer the infection persists, the greater the damage to lung tissue,” said Martina Flammer, MD, MBA, chief medical officer, Insmed.¹
What was ENCORE trial design and primary results in MAC lung disease?
The Priority Review is supported by data from ENCORE, a phase 3b, randomized, double-blind, placebo-controlled trial evaluating amikacin liposome inhalation suspension in treatment-naive MAC lung disease.² The trial enrolled 425 patients across 177 global sites, of whom 82.4% had a first MAC infection and 17.6% had a second or third infection.¹ Patients were randomized 1:1 to daily amikacin liposome inhalation suspension plus azithromycin 250 mg and ethambutol 15 mg/kg (n = 213) or placebo plus the same background multidrug regimen (n = 212), for 12 months of treatment followed by 3 months off treatment.¹
The primary endpoint, change in Respiratory Symptom Score from baseline at month 13, was met, according to Insmed.¹ Secondary endpoints, including multiplicity-controlled culture conversion measures, were also met with statistical significance.¹ Insmed did not disclose exact p-values or numerical score changes for the primary or secondary endpoints in its announcement.¹
Patients receiving amikacin liposome inhalation suspension achieved earlier, greater, and more durable culture conversion compared with the placebo-plus-multidrug-therapy arm, according to Insmed.¹ The company did not report specific culture conversion rates or time-to-conversion data in its topline release.¹
Key Facts
What is the FDA reviewing for ARIKAYCE?
The FDA granted Priority Review to Insmed's sNDA seeking full approval of ARIKAYCE for newly diagnosed and recurrently infected MAC lung disease, expanding beyond its current limited-population approval for refractory disease, with a PDUFA date of January 28, 2027.¹
What did the ENCORE trial show?
In the phase 3b ENCORE trial, ARIKAYCE plus background multidrug therapy met its primary endpoint of Respiratory Symptom Score change at month 13 and multiplicity-controlled secondary culture conversion endpoints versus placebo plus background therapy in 425 treatment-naive patients with MAC lung disease.¹
What is ARIKAYCE currently approved for?
ARIKAYCE is approved under the Limited Population Pathway for Antibacterial and Antifungal Drugs for refractory MAC lung disease in patients who have failed at least 6 months of multidrug therapy without negative sputum culture conversion.¹
What was ARIKAYCE safety profile and regulatory pathway in MAC lung disease?
No new safety signals were observed in ENCORE compared with ARIKAYCE's existing safety profile, according to Insmed.¹ In prior clinical experience, the most common adverse events (AEs) occurring in at least 5% of amikacin liposome inhalation suspension-treated patients and at a higher incidence than background regimen alone included dysphonia (47% vs 1%), cough (39% vs 17%), bronchospasm (29% vs 11%), hemoptysis (18% vs 13%), and ototoxicity (17% vs 10%).³ Amikacin liposome inhalation suspension carries a boxed warning for hypersensitivity pneumonitis, bronchospasm, and hemoptysis.³
Insmed did not report nephrotoxicity rates exceeding those of the background multidrug regimen alone.³ The company did not disclose ENCORE-specific adverse event frequencies by treatment arm for most reactions in its announcement.¹
Priority Review status indicates the FDA has determined ARIKAYCE, if approved for this expanded indication, would represent a significant improvement in safety or effectiveness for a serious condition compared with standard applications.¹ Insmed said it will continue to work with the FDA through the review process ahead of the January 28, 2027, PDUFA date.¹
References
Insmed. FDA grants Priority Review to Insmed's sNDA for ARIKAYCE (amikacin liposome inhalation suspension) for treatment of MAC lung disease, with PDUFA target action date set for January 28, 2027. Published September 21, 2026. Accessed September 21, 2026. https://investor.insmed.com/2026-09-21-FDA-Grants-Priority-Review-to-Insmeds-sNDA-for-ARIKAYCE-R-amikacin-liposome-inhalation-suspension-for-Treatment-of-MAC-Lung-Disease-With-PDUFA-Target-Action-Date-Set-for-January-28,-2027
ClinicalTrials.gov. Amikacin liposome inhalation suspension for newly diagnosed Mycobacterium avium complex lung disease (ENCORE). Identifier: NCT04677543. Accessed September 21, 2026. https://clinicaltrials.gov/study/NCT04677543
DailyMed. ARIKAYCE- amikacin suspension [package insert]. National Library of Medicine. Accessed September 21, 2026. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=499ab990-2b21-474f-aaba-d86388965f40
