X0306 4 2021-06-15 0 0001817713 Janux Therapeutics, Inc. JANX 0001055951 ORBIMED ADVISORS LLC 601 LEXINGTON AVENUE, 54TH FLOOR NEW YORK NY 10022 1 0 0 0 0001845804 OrbiMed Capital GP VIII LLC 601 LEXINGTON AVENUE, 54TH FLOOR NEW YORK NY 10022 1 0 0 0 0001808744 OrbiMed Genesis GP LLC 601 LEXINGTON AVENUE, 54TH FLOOR NEW YORK NY 10022 1 0 0 0 Common Stock 2021-06-15 4 C 0 1348421 A 1348421 I See footnotes Common Stock 2021-06-15 4 C 0 823742 A 2172163 I See footnotes Common Stock 2021-06-15 4 P 0 588203 17.00 A 2760366 I See footnotes Common Stock 2021-06-15 4 C 0 164748 A 164748 I See footnotes Common Stock 2021-06-15 4 P 0 117650 17.00 A 282398 I See footnotes Series A Convertible Preferred Stock 2021-06-15 4 C 0 1052632 D Common Stock 1348421 0 I See footnotes Series B Convertible Preferred Stock 2021-06-15 4 C 0 643046 D Common Stock 823742 0 I See footnotes Series B Convertible Preferred Stock 2021-06-15 4 C 0 128609 D Common Stock 164748 0 I See footnotes Each share of Series A Convertible Preferred Stock and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") converted into 1.281 shares of Common Stock upon the closing of the Issuer's initial public offering without payment of further consideration. Share numbers give effect to such conversion. The Preferred Stock had no expiration date. The securities are held of record by OrbiMed Private Investments VIII, LP ("OPI VIII"). OrbiMed Capital GP VIII LLC ("GP VIII") is the general partner of OPI VIII and OrbiMed Advisors LLC ("Advisors") is the managing member of GP VIII. By virtue of such relationships, GP VIII and Advisors may be deemed to have voting and investment power with respect to the shares held by OPI VIII and as a result may be deemed to have beneficial ownership of such shares. Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and Jonathan T. Silverstein. This report on Form 4 is jointly filed by Advisors, GP VIII, and OrbiMed Genesis GP LLC ("Genesis GP"). Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. Advisors and GP VIII have designated a representative, Peter Thompson, an employee of Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such entity or person is a beneficial owner of such securities for purpose of Section 16 of the Exchange Act, or for any other purpose. The shares were purchased in the Issuer's initial public offering. The securities are held of record by OrbiMed Genesis Master Fund, L.P. ("Genesis Fund"). Genesis GP is the general partner of Genesis Fund and Advisors is the managing member of Genesis GP. By virtue of such relationships, Genesis GP and Advisors may be deemed to have voting and investment power with respect to the shares held by Genesis Fund and as a result may be deemed to have beneficial ownership of such shares. Advisors exercises investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and Jonathan T. Silverstein. OrbiMed Advisors LLC, By:/s/ Douglas Coon, Chief Compliance Officer 2021-06-16 OrbiMed Capital GP VIII LLC, By: /s/ Douglas Coon, Chief Compliance Officer 2021-06-16 OrbiMed Genesis GP LLC, By: /s/ Douglas Coon, Chief Compliance Officer 2021-06-16