Insmed (INSM) Q1 FY26 earnings call: guidance and Q&A

BRINSUPRI's launch continues to exceed expectations, delivering 44% sequential growth in Q1 FY26, significantly outpacing past specialty respiratory launch analogs which averaged 9% sequential growth in their first calendar Q1. The company estimates approximately 3,500 'ready and waiting' patients were embedded in Q4 FY25 new patient starts and 1,500 in Q1 FY26. As this initial surge concludes, organic demand is steadily growing, with sequential growth expected from Q2 FY26 through the rest of the year. The company did not raise BRINSUPRI's price at the start of 2026, and inventory stocking impact was negligible.

BRINSUPRI benefits from a favorable payer access environment, with an impressive nearly 90% approval rate for patients processed through specialty pharmacies since launch. The time required for payer approval has been less than a week for the majority of patients, well ahead of internal benchmarks. Over 80% of BRINSUPRI patients have enrolled in the inLighten patient support program, reflecting strong engagement. Prescription refill rates are faster than industry benchmarks, at nearly every 30 days, and continuation rates are tracking slightly above statin analogs (70% at 6 months), indicating positive patient experience and adherence.

The company is focused on broadening and deepening BRINSUPRI prescribing. As of Q1 FY26, cumulative total writers exceeded 5,000, representing over 25% of all U.S. pulmonologists. There remains significant opportunity to expand the prescriber base, particularly in large institutions that have yet to write their first prescription. Additionally, 20% of BRINSUPRI prescribers have written for at least 5 patients, indicating growing comfort and experience with the medicine. Management anticipates that positive patient and physician feedback, along with medical gatherings like ATS, will further encourage prescribing.

ARIKAYCE continues to show year-over-year growth in its eighth year. The Phase IIIb ENCORE trial in newly diagnosed NTM MAC patients demonstrated statistically significant outcomes on the patient-reported respiratory symptom score primary endpoint and earlier, greater, and more durable culture conversion. These data make a compelling case for earlier use of ARIKAYCE, with over 80% of patients achieving negative sputum cultures in 6 months, compared to 30% in the CONVERT study. The addressable market for ARIKAYCE could expand from 30,000 to over 200,000 patients, potentially turning it into a blockbuster brand with a $1 billion+ peak sales opportunity.

TPIP represents a substantial late-stage opportunity with four Phase III trials underway or planned. The first site for the Phase III PALM PAH study has opened, and enrollment is progressing in the PALM-ILD study across seven countries, including the U.S. despite competition. Data from the Phase IIb 24-month open-label extension study in PAH is expected in Q3 FY26, including safety and efficacy measures through 12 months. The company is finalizing trial designs for PPF and IPF, with enthusiasm for TPIP's potential given recent positive data for other treprostinil products in IPF, suggesting TPIP could offer greater benefits due to higher dose delivery.

Insmed is accelerating efforts to increase awareness and proper diagnosis of bronchiectasis. The company launched the 'Suspect BE' campaign featuring Ty Pennington, drawing on his personal experience. The American Thoracic Society (ATS) has also initiated an effort to address underdiagnosis by analyzing electronic health records across seven academic medical systems. This initiative aims to identify misdiagnosis patterns, pilot scalable solutions like EHR-based prompts, and determine the number of COPD/asthma patients with undiagnosed bronchiectasis, potentially driving better outcomes and increasing the likelihood of appropriate diagnosis.

As of Q1 FY26, Insmed had approximately $1.2 billion in cash, cash equivalents, and marketable securities. The underlying cash burn was within the range of the past year and is expected to decline as revenues ramp faster than spending. The company believes it can achieve sustainable cash flow positivity in 2027 without needing additional capital, assuming no significant increase in expense base from business development. Insmed is actively pursuing select business development opportunities to augment its pipeline, focusing on programs that offer asymmetric return potential and broader applicability across disease states.