GORDON CARL L bought BLSM

Footnotes

Each share of Series A Preferred Stock and Series B Preferred Stock (together, the "Preferred Stock") automatically converted into 1 share of the Issuer's Common Stock upon the closing of the Issuer's initial public offering on August 10, 2026 without payment of consideration. The Preferred Stock has no expiration date.; These securities are held directly by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII. OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and OrbiMed Advisors may be deemed to have voting power and investment power over the securities held by OPI VIII and as a result, may be deemed to have beneficial ownership over such securities. OrbiMed Advisors exercises voting and investment power through a management committee comprised of the Reporting Person, W. Carter Neild, and Geoffrey C. Hsu, each of whom disclaims beneficial ownership of the shares held by OPI VIII.; Each of the Reporting Person, OrbiMed Advisors, and GP VIII disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report shall not be deemed an admission that any of the Reporting Person, OrbiMed Advisors, or GP VIII is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.