Commodore Capital LP Reports New 9.9% Passive Stake in Karyopharm Therapeutics Inc.

On April 2, 2026, Commodore Capital LP and its affiliates filed a Schedule 13G disclosing a new 9.9% stake in Karyopharm Therapeutics Inc. (KPTI). The filing indicates that Commodore Capital LP, acting as investment manager to Commodore Capital Master LP, has acquired beneficial ownership of 1,950,000 shares of Common Stock. The transaction event date was March 26, 2026. Managing partners Michael Kramarz and Robert Egen Atkinson are also named as reporting persons due to their shared investment discretion over the securities. The ownership percentage is based on approximately 19.6 million shares outstanding as reported by the issuer in March 2026. This filing is made under Rule 13d-1(c), certifying that the shares were not acquired for the purpose of changing or influencing the control of the issuer. The reporting persons share voting and dispositive power over the entire block of 1,950,000 shares.