ORBIMED ADVISORS LLC bought ETRA

Footnotes

Each share of Series A Convertible Preferred Stock, Series B Convertible Preferred Stock and Series C Convertible Preferred Stock (collectively, the "Preferred Stock") automatically converted into 1 share of Common Stock upon the closing of the Issuer's initial public offering on September 21, 2026 without payment of further consideration. The Preferred Stock has no expiration date.; These securities are held directly by OrbiMed Genesis Master Fund, L.P. ("OrbiMed Genesis"). OrbiMed Genesis GP LLC ("Genesis GP") is the general partner of OrbiMed Genesis. OrbiMed Advisors is the managing member of Genesis GP. By virtue of such relationships, Genesis GP and OrbiMed Advisors may be deemed to have voting power and investment power over the securities held by OrbiMed Genesis 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 Carl L. Gordon, W. Carter Neild, and Geoffrey C. Hsu, each of whom disclaims beneficial ownership of the shares held by OrbiMed Genesis.; This report on Form 4 is jointly filed by OrbiMed Advisors, GP VII and Genesis GP. Each of the Reporting Persons 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. The Reporting Persons have designated Carl L. Gordon, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any of such entity or person is a beneficial owner of such securities for purposes of Section 16 of the Exchange Act, or for any other purpose.