X0306 4 2020-12-10 0 0001382101 SUTRO BIOPHARMA, INC. STRO 0001296771 Freund John Gordon SKYLINE VENTURES 525 UNIVERSITY AVE., SUITE 1350 PALO ALTO CA 94301 1 0 0 0 Common Stock 2020-12-10 4 J 0 118735 0.00 D 0 I By Skyline Venture Management V, LLC Common Stock 2020-12-10 4 J 0 56327 0.00 A 56327 I By partnership The shares reported on this form represent pro rata distributions, and not sales or purchases, of securities by the reporting entity to its partners. These securities are held of record by Skyline Venture Management V, LLC ("Skyline Management"), of which the reporting person, a member of the issuer's board of directors, together with Yasunori Kaneko, are the managing directors, and each may be deemed to share voting and investment power over the securities held by Skyline Management. The reporting person disclaims beneficial ownership over such securities except to the extent of his pecuniary interest therein, and the inclusion of these securities in this report shall not be deemed an admission of beneficial ownership of the reported securities for purposes of Section 16 or for any other purposes. These securities are held of record by the John Freund Family Partnership IV, L.P. /s/ Edward C. Albini as attorney-in-fact for John G. Freund 2020-12-14