X0206 3 2016-07-19 0 0001628738 Audentes Therapeutics, Inc. BOLD 0001055951 ORBIMED ADVISORS LLC 601 LEXINGTON AVE., 54TH FLOOR NEW YORK NY 10022 1 0 1 0 0001055949 ISALY SAMUEL D 601 LEXINGTON AVE., 54TH FLOOR NEW YORK NY 10022 1 0 1 0 0001502240 OrbiMed Capital GP IV LLC 601 LEXINGTON AVE., 54TH FLOOR NEW YORK NY 10022 1 0 1 0 Common Stock 224238 I See Footnotes Series Seed Preferred Stock Common Stock 627867 I See Footnotes Series A Preferred Stock Common Stock 2511441 I See Footnotes Series B Preferred Stock Common Stock 1071992 I See Footnotes Series C Preferred Stock Common Stock 332766 I See Footnotes These securities are held of record by OrbiMed Private Investments IV, LP ("OPI IV"). OrbiMed Capital GP IV LLC ("GP IV") is the sole general partner of OPI IV, and OrbiMed Advisors LLC ("Advisors") is the managing member of GP IV. Samuel D. Isaly ("Isaly"), a natural person, is the managing member of and owner of a controlling interest in Advisors. By virtue of such relationships, GP IV, Advisors and Isaly may be deemed to have voting and investment power over the securities held by OPI IV and as a result may be deemed to have beneficial ownership over such securities. This report on Form 3 is jointly filed by GP IV, Advisors, and Isaly. 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 or his pecuniary interest therein, if any. The reporting persons have designated a representative, currently Jonathan Silverstein, a member of Advisors, to serve on the issuer's board of directors. This report shall not be deemed an admission that any of the reporting persons is a beneficial owner of such securities for the purposes of Section 16 of the Exchange Act, or for any other purposes. Each share of the issuer's Series Seed Preferred Stock will automatically convert into 1 share of the issuer's Common Stock immediately upon the closing of the issuer's initial public offering ("IPO") and has no expiration date. Each share of the issuer's Series A Preferred Stock will automatically convert into 1 share of the issuer's Common Stock immediately upon the closing of the issuer's IPO and has no expiration date. Each share of the issuer's Series B Preferred Stock will automatically convert into 1 share of the issuer's Common Stock immediately upon the closing of the issuer's IPO and has no expiration date. Each share of the issuer's Series C Preferred Stock will automatically convert into 1 share of the issuer's Common Stock immediately upon the closing of the issuer's IPO and has no expiration date. /s/ Samuel D. Isaly 2016-07-19