Insmed Announces Departure of CFO Sara Bonstein; Reaffirms 2026 Guidance

Executive Summary

On October 5, 2026, Insmed Incorporated filed a Form 8-K under Items 5.02, 7.01, and 9.01 announcing the departure of Chief Financial Officer Sara Bonstein, effective October 30, 2026. The company simultaneously reaffirmed its full-year 2026 financial guidance and confirmed Ms. Bonstein will participate in the Q3 2026 financial results call scheduled for October 29, 2026.

Key Event Details

• Officer: Sara Bonstein, Chief Financial Officer
• Effective Departure Date: October 30, 2026
• Reason: Ms. Bonstein is stepping down to pursue broader leadership opportunities. The filing confirms her departure is not related to any disagreement regarding accounting practices, financial statements, internal controls, or operations.
• Severance & Terms: Ms. Bonstein will receive benefits specified under Section 6.e of her Amended and Restated Employment Agreement dated April 1, 2022.
• Succession Plan: The company has retained an executive search firm to identify a successor CFO.

Guidance Reaffirmation

Alongside the transition announcement, Insmed reaffirmed its full-year 2026 guidance:

• BRINSUPRI® (brensocatib): $1.25 billion to $1.40 billion
• ARIKAYCE® (amikacin liposome inhalation suspension): $450 million to $470 million

Market Implications

Executive turnover in the CFO seat typically introduces short-term uncertainty. However, the orderly transition through the Q3 earnings call, explicit confirmation of no accounting disputes, and reaffirmation of strong full-year commercial guidance for both key assets help mitigate potential negative sentiment.