INSM Stock Gains After Arikayce Hits Goal in Label Expansion Study

Shares of Insmed INSM gained nearly 6% on Monday after the company reported positive top-line results from the phase IIIb ENCORE study evaluating Arikayce for label expansion in mycobacterium avium complex (MAC) lung disease.

This late-stage study evaluated the once-daily combination of Arikayce and multidrug therapy (an antibiotic combination of azithromycin and ethambutol) against placebo in newly-diagnosed MAC lung disease patients who had not received antibiotics.

The study met its primary endpoint — patients treated with the Arikayce regimen for 13 months achieved statistically significant and clinically meaningful improvements in respiratory symptom score (RSS), a patient-reported outcome measure. The combination therapy met several key secondary endpoints, including culture conversion at months six, 12, 13 and 15.

Arikayce was approved by the FDA in 2018 under the accelerated pathway for the treatment of refractory MAC lung disease as part of a combination antibacterial drug regimen in adult patients with limited or no alternative treatment options. It is approved for similar indications in Europe and Japan.

The ENCORE study data will support regulatory submissions seeking label expansion in newly diagnosed patients, while serving as a confirmatory study to convert Arikayce’s accelerated approval to full approval. Regulatory submissions in the United States and Japan are expected in the second half of the year.

INSM Stock Performance

The ENCORE results were viewed positively by several investors, given the potential for a significant expansion in Arikayce’s addressable market. The company has previously estimated the total addressable market (TAM) for refractory MAC lung disease at around 30,000 patients across the United States, Europe and Japan. Expansion into newly diagnosed patients could increase the TAM to more than 200,000 patients across these markets. This broader opportunity could support blockbuster-level sales for the drug.

Shares of Insmed have underperformed the industry in the year-to-date period, as seen in the chart below.

Image Source: Zacks Investment Research

Arikayce: A Key Revenue Generator for Insmed

Arikayce was the first marketed product in Insmed’s portfolio. Despite approval in a limited treatment population, sales of the drug have been rising consistently, driven by encouraging demand across all markets.

Sales of the drug rose 19% year over year to nearly $434 million in 2025. For full-year 2026, the company expects to record sales between $450 million and $470 million, suggesting 6% year-over-year growth at the midpoint.

INSM’s Zacks Rank

Insmed currently carries a Zacks Rank #3 (Hold).

Insmed, Inc. Price

Insmed, Inc. price | Insmed, Inc. Quote

Key Picks Among Biotech Stocks

Some better-ranked stocks from the sector are Catalyst Pharmaceuticals CPRX and ANI Pharmaceuticals ANIP. While CPRX sports a Zacks Rank #1 (Strong Buy) at present, ANIP carries a Zacks Rank #2 (Buy). You can see the complete list of today’s Zacks #1 Rank stocks here.

Over the past 60 days, estimates for Catalyst Pharmaceuticals’ 2026 EPS have risen from $2.55 to $2.87, while those for 2027 have increased from $2.85 to $3.25. CPRX shares have registered breakeven growth year to date.

Catalyst Pharmaceuticals’ earnings beat estimates in each of the trailing four quarters, with the average surprise being 35.19%.

Over the past 60 days, estimates for ANI Pharmaceuticals’ 2026 EPS have increased from $8.28 to $8.99, while the same for 2027 have risen from $9.25 to $10.10. The stock has declined 6% year to date.

ANI Pharmaceuticals’ earnings beat estimates in each of the trailing four quarters, with the average surprise being 22.21%.

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This article originally published on Zacks Investment Research (zacks.com).

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