Rare Lung Disease Drug News: CEO of US Biotech Firm Sells $20 Million Stake

Insmed Incorporated (NASDAQ: INSM) on the 23rd announced that its Phase 3b ENCORE post-approval clinical trial of ARIKAYCE, a treatment for a rare lung disease, met key endpoints—including improvement in respiratory symptom scores at the 13-month mark and negative culture conversion—and said it plans to submit additional applications in the second half of 2026 to the U.S. Food and Drug Administration (FDA) and Japan’s Pharmaceuticals and Medical Devices Agency (PMDA) to expand the indication and convert its conditional approval into full approval. Based on these results, the company expects that the treatable population in the U.S. and Japan could expand from approximately 30,000 existing refractory MAC lung disease patients to include up to an additional 200,000 newly diagnosed cases.

Earlier on the 5th, CEO William Lewis exercised two tranches of stock options, converting about 10,000 options into new shares and, under a pre-established Rule 10b5-1 trading plan, sold them all on the open market, generating roughly $1.5 million (around KRW 2 billion) in proceeds. He paid about $96,000 (approximately KRW 100 million) to exercise the options, and filings show that after the transaction he still holds approximately $44 million (around KRW 60 billion) in shares on an outright basis.

In its late-February report of full-year 2025 results, Insmed provided 2026 revenue guidance of at least $1.0 billion for BRINSUPRI and $450–470 million for ARIKAYCE, driven by ARIKAYCE sales growth and the launch of BRINSUPRI. As of that date, the company held about $1.4 billion in cash and cash equivalents (approximately KRW 1.9 trillion). ()

Insmed is a biotechnology company headquartered in Bridgewater, New Jersey, whose flagship product is ARIKAYCE—an inhaled antibiotic approved for non-tuberculous mycobacterial (MAC) lung disease—and is expanding its pipeline in severe respiratory diseases. () According to the company, the ENCORE results constitute core data for converting ARIKAYCE’s conditional approval into full U.S. approval and expanding its indications to include Japan, and will be central to its future regulatory review and market expansion strategy.