—First-in-Disease and First-in-Class Therapy Approved in Japan for Patients With Non-Cystic Fibrosis Bronchiectasis (NCFB), a Progressive Disease That Can Lead to Permanent Lung Damage—

BRIDGEWATER, N.J., Aug. 24, 2026 /PRNewswire/ -- Insmed Incorporated (NASDAQ:INSM), a people-first global biopharmaceutical company striving to deliver first- and best-in-class therapies to transform the lives of patients facing serious diseases, today announced that Japan's Ministry of Health, Labour and Welfare (MHLW) has approved BRINSUPRI^® (brensocatib 25-mg tablet), an oral, once-daily treatment for non-cystic fibrosis bronchiectasis (NCFB) in adults and pediatric patients 12 years and older. BRINSUPRI, the first and only MHLW-approved treatment for NCFB, finally gives patients with NCFB and clinicians who treat the disease an option to manage this chronic and progressive disease that can lead to permanent lung damage and lung function decline. With this approval, BRINSUPRI is now approved for use in the U.S., Europe, and Japan.

"Today's approval of BRINSUPRI represents a profound milestone for people living with bronchiectasis in Japan," said Martina Flammer, M.D., MBA, Chief Medical Officer of Insmed. "Patients have long faced a relentless cycle of exacerbations and declining lung function, with available care largely limited to symptom management. This approval reflects the contributions of patients and researchers who made this clinical evidence possible, as well as Insmed's enduring commitment to developing therapies that address significant unmet needs in respiratory diseases, including bronchiectasis care."

The approval of BRINSUPRI by the MHLW for the treatment of patients living with NCFB is based on results from the Phase 3 ASPEN study, which demonstrated that brensocatib significantly reduced pulmonary exacerbations compared with placebo over the 52-week treatment period and met multiple key secondary endpoints, including significantly prolonging the time to first exacerbation and significantly increasing the proportion of patients remaining exacerbation-free over the treatment period. Patients treated with brensocatib 25 mg also demonstrated significantly lower lung function decline at week 52, as measured by post bronchodilator forced expiratory volume in 1 second (FEV1), a standard measure of lung function. Brensocatib was generally well tolerated in the study. The most common treatment-emergent adverse events (TEAEs) occurring in at least 5.0% of patients were COVID-19, nasopharyngitis, cough, and headache.

"In patients living with bronchiectasis, recurrent exacerbations represent a substantial disease burden, making daily life harder to manage and affecting long-term clinical outcomes," said Makoto Nakamura, Senior Vice President, General Manager, Japan for Insmed. "By targeting key drivers of chronic airway inflammation, BRINSUPRI offers a new treatment option for appropriate patients in Japan. We are proud of this important milestone and look forward to continuing to support the bronchiectasis community as we advance innovation in this disease area."

About Bronchiectasis

Non-cystic fibrosis bronchiectasis (NCFB) is a chronic, progressive, and inflammatory lung disease that causes the airways to become permanently widened due to a cycle of infection, inflammation, lung tissue damage, and mucociliary dysfunction. Patients with NCFB often experience repeated exacerbations, requiring antibiotic therapy and/or hospitalizations. Symptoms include chronic cough, excessive sputum production, shortness of breath, fatigue, and repeated respiratory infections, which can worsen the underlying disease.

About BRINSUPRI

BRINSUPRI^® (brensocatib) is a small molecule, once-daily, oral, reversible inhibitor of dipeptidyl peptidase 1 (DPP1), designed to inhibit the activation of enzymes (neutrophil serine proteases) in neutrophils that are key drivers of chronic airway inflammation in NCFB. The therapy is approved in the United States as BRINSUPRI (brensocatib 10 mg and 25 mg tablets) and indicated for the treatment of non-cystic fibrosis bronchiectasis (NCFB) in adult and pediatric patients 12 years of age or older. In the European Union and United Kingdom, BRINSUPRI (brensocatib 25 mg tablets) is approved for the treatment of NCFB in patients 12 years of age and older with two or more exacerbations in the prior 12 months. In Japan, BRINSUPRI (brensocatib 25 mg tablets) is approved for the treatment of patients with non-cystic fibrosis bronchiectasis (NCFB) in adult and pediatric patients 12 years and older.

BRINSUPRI^® (brensocatib) U.S. INDICATION AND IMPORTANT SAFETY INFORMATION

Indication in the U.S.

BRINSUPRI is indicated for the treatment of non-cystic fibrosis bronchiectasis (NCFB) in adult and pediatric patients 12 years of age and older.

Important Safety Information in the U.S.

WARNINGS AND PRECAUTIONS

Dermatologic Adverse Reactions

Treatment with BRINSUPRI is associated with an increase in dermatologic adverse reactions, including rash, dry skin, and hyperkeratosis. Monitor patients for development of new rashes or skin conditions and refer patients to a dermatologist for evaluation of new dermatologic findings.

Gingival and Periodontal Adverse Reactions

Treatment with BRINSUPRI is associated with an increase in gingival and periodontal adverse reactions. Refer patients to dental care services for regular dental checkups while taking BRINSUPRI. Advise patients to perform routine dental hygiene.

Live Attenuated Vaccines

It is unknown whether administration of live attenuated vaccines during BRINSUPRI treatment will affect the safety or effectiveness of these vaccines. The use of live attenuated vaccines should be avoided in patients receiving BRINSUPRI.

ADVERSE REACTIONS

The most common adverse reactions ≥2% in the ASPEN trial included upper respiratory tract infection, headache, rash, dry skin, hyperkeratosis, and hypertension. The safety profile for adult patients with NCFB in WILLOW was generally similar to ASPEN, except for a higher incidence of gingival and periodontal adverse reactions.

Less Common Adverse Reactions

Liver Function Test Elevations

In ASPEN, there was an increase from baseline in average ALT, AST, and alkaline phosphatase levels at all time points from Week 4 through Week 56 in both BRINSUPRI 10 mg and 25 mg arms compared to placebo. The incidence of ALT >3X upper limit of normal (ULN) was 0%, 1.2%, and 0.9%; the incidence of AST >3X ULN was 0.2%, 0.3%, and 0.5%; and the incidence of alkaline phosphatase >1.5X ULN was 2.5%, 4.1%, and 4.0% in patients treated with placebo and BRINSUPRI 10 mg and 25 mg, respectively.

Skin Cancers

In ASPEN, the incidence of skin cancers among patients treated with BRINSUPRI 10 mg and 25 mg was 0.5% and 1.9%, respectively, compared to 1.1% in placebo-treated patients.

Alopecia

In ASPEN, the incidence of alopecia among patients treated with BRINSUPRI 10 mg and 25 mg was 1.5% and 1.6% respectively, compared to 0.4% in placebo-treated patients.

USE IN SPECIFIC POPULATIONS

Pregnancy: There are no clinical data on the use of BRINSUPRI in pregnant women.

Lactation: There is no information regarding the presence of BRINSUPRI and/or its metabolite(s) in human milk, the effects on the breastfed infant, or the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for BRINSUPRI and any potential adverse effects on the breastfed child from BRINSUPRI or from the underlying maternal condition.

Pediatric use: The safety and effectiveness of BRINSUPRI for the treatment of NCFB have been established in pediatric patients aged 12 years and older. Common adverse reactions in pediatric patients aged 12 years and older enrolled in ASPEN were consistent with those in adults. The safety and effectiveness of BRINSUPRI have not been established in pediatric patients younger than 12 years of age.

Please see full US Prescribing Information.

About Insmed

Insmed Incorporated is a people-first global biopharmaceutical company striving to deliver first- and best-in-class therapies to transform the lives of patients facing serious diseases. The Company is advancing a diverse portfolio of approved and mid- to late-stage investigational medicines — including two approved therapies to treat chronic, debilitating lung diseases — as well as cutting-edge drug discovery focused on serving patient communities where the need is greatest. Insmed's commercial portfolio and clinical pipeline are organized around three therapeutic areas: Respiratory, Immunology & Inflammation, and Neuro & Other Rare. The Company's research engine is advancing a wide range of technologies and modalities, including gene therapy, AI-driven protein engineering, RNA end-joining, and synthetic rescue, in the pursuit of future pipeline candidates.

Headquartered in Bridgewater, New Jersey, Insmed has offices and research locations throughout the United States, Europe, and Japan. Insmed is proud to be recognized as one of the best employers in the biopharmaceutical industry, including spending five consecutive years as the No. 1 Science Top Employer. Visit www.insmed.com to learn more or follow us on LinkedIn, Instagram, YouTube, and X.

Forward-looking Statements

This press release contains forward-looking statements that involve substantial risks and uncertainties. "Forward-looking statements," as that term is defined in the Private Securities Litigation Reform Act of 1995, are statements that are not historical facts and involve a number of risks and uncertainties. Words herein such as "may," "will," "should," "could," "would," "expects," "plans," "anticipates," "believes," "estimates," "projects," "predicts," "intends," "potential," "continues," and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances), may identify forward-looking statements.

The forward-looking statements in this press release are based upon the Company's current expectations and beliefs, and involve known and unknown risks, uncertainties and other factors, which may cause the Company's actual results, performance and achievements and the timing of certain events, to differ materially from the results, performance, achievements or timings discussed, projected, anticipated or indicated in any forward-looking statements. Such risks, uncertainties and other factors include, among others, the following: failure to successfully commercialize BRINSUPRI in the U.S., Europe or Japan, or to maintain U.S., European or Japanese approval for BRINSUPRI; uncertainties in the degree of market acceptance of BRINSUPRI by physicians, patients, third-party payors and others in the health care community; inaccuracies in the Company's estimates of the size of the potential markets for BRINSUPRI or in data the Company has used to identify physicians; expected rates of patient uptake, duration of expected treatment, or expected patient adherence or discontinuation rates; the Company's inability to obtain adequate reimbursement from government or third-party payors for BRINSUPRI or acceptable prices for BRINSUPRI; development of unexpected safety or efficacy concerns related to BRINSUPRI, including the risk that data generated in further clinical trials of brensocatib may not be consistent with the results of the ASPEN study, which may result in changes to the product label and may adversely affect sales, or result in withdrawal of BRINSUPRI from the market; failure by us to comply with agreements related to brensocatib, including our license agreement with AstraZeneca AB; risk that health care legislation or other government action materially adversely affects the Company's business; and failure of third parties on which the Company is dependent to manufacture sufficient quantities of brensocatib for commercial needs, or to comply with the Company's agreements or laws and regulations that impact the Company's business or agreements with the Company.

The Company may not actually achieve the results, plans, intentions, or expectations indicated by the Company's forward-looking statements, because, by their nature, forward-looking statements involve risks and uncertainties because they relate to events and depend on circumstances that may or may not occur in the future. For additional information about the risks and uncertainties that may affect the Company's business, please see the factors discussed in Item 1A, "Risk Factors," in the Company's Annual Report on Form 10-K for the year ended December 31, 2025, and any subsequent Company filings with the Securities and Exchange Commission (SEC).

The Company cautions readers not to place undue reliance on any such forward-looking statements, which speak only as of the date of this press release. The Company disclaims any obligation, except as specifically required by law and the rules of the SEC, to publicly update or revise any such statements to reflect any change in expectations or in events, conditions or circumstances on which any such statements may be based, or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements.

Contact:

Investors:

Sara Bonstein

Chief Financial Officer

investor.relations@insmed.com

Media:

Claire Mulhearn

Vice President, Corporate Communications

media@insmed.com

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SOURCE Insmed Incorporated