X0609 4 2026-08-10 0 0002056611 Latigo Biotherapeutics, Inc. LTGO 0001749591 Westlake BioPartners Fund I, L.P. false C/O WESTLAKE BIOPARTNERS, LLC 3075 TOWNSGATE ROAD, SUITE 140 WESTLAKE VILLAGE CA 91361 0 0 1 0 0002007650 Westlake BioPartners GP I, LLC false C/O WESTLAKE BIOPARTNERS, LLC 3075 TOWNSGATE ROAD, SUITE 140 WESTLAKE VILLAGE CA 91361 0 0 1 0 0001811947 Westlake BioPartners Fund II, L.P. false C/O WESTLAKE BIOPARTNERS, LLC 3075 TOWNSGATE ROAD, SUITE 140 WESTLAKE VILLAGE CA 91361 0 0 1 0 0001811948 Westlake BioPartners GP II, LLC false C/O WESTLAKE BIOPARTNERS, LLC 3075 TOWNSGATE ROAD, SUITE 140 WESTLAKE VILLAGE CA 91361 0 0 1 0 0001811946 Westlake BioPartners Opportunity Fund I, L.P. false C/O WESTLAKE BIOPARTNERS, LLC 3075 TOWNSGATE ROAD, SUITE 140 WESTLAKE VILLAGE CA 91361 0 0 1 0 0001811945 Westlake BioPartners Opportunity GP I, LLC false C/O WESTLAKE BIOPARTNERS, LLC 3075 TOWNSGATE ROAD, SUITE 140 WESTLAKE VILLAGE CA 91361 0 0 1 0 0 Common Stock 2026-08-10 4 C 0 938979 A 1368532 I See footnote Common Stock 2026-08-10 4 C 0 3547842 A 4916374 I See footnote Common Stock 2026-08-10 4 C 0 1027635 A 5944009 I See footnote Common Stock 2026-08-10 4 C 0 3464072 A 3510927 I See footnote Common Stock 2026-08-10 4 C 0 1484401 A 4995328 I See footnote Common Stock 2026-08-10 4 C 0 165519 A 5160847 I See footnote Common Stock 2026-08-10 4 C 0 2066857 A 2094813 I See footnote Series Seed Convertible Preferred Stock 2026-08-10 4 C 0 938979 D Common Stock 938979 0 I See footnote Series A Convertible Preferred Stock 2026-08-10 4 C 0 3547842 D Common Stock 3547842 0 I See footnote Series A-2 Convertible Preferred Stock 2026-08-10 4 C 0 1027635 D Common Stock 1027635 0 I See footnote Series A-2 Convertible Preferred Stock 2026-08-10 4 C 0 3464072 D Common Stock 3464072 0 I See footnote Series B Convertible Preferred Stock 2026-08-10 4 C 0 1484401 D Common Stock 1484401 0 I See footnote Series A-2 Convertible Preferred Stock 2026-08-10 4 C 0 2066857 D Common Stock 2066857 0 I See footnote Convertible Promissory Note 2026-08-10 4 C 0 165519 D Common Stock 165519 0 I See footnote Each share of Series Seed Convertible Preferred Stock, Series A Convertible Preferred Stock, Series A-2 Convertible Preferred Stock and Series B Convertible Preferred Stock (collectively, the "Preferred Stock") converted automatically into 1 share 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. Shares held directly by Westlake BioPartners Fund I, L.P. ("Fund I"). The general partner of Fund I is Westlake BioPartners GP I, LLC ("GP I"). GP I may be deemed to share voting and dispositive power with regard to the shares held directly by Fund I. Beth Seidenberg ("Seidenberg") is the sole managing director of GP I and has voting and dispositive power over the shares held by Fund I. Seidenberg disclaims Section 16 beneficial ownership of the shares reported herein except to the extent of her pecuniary interest therein, if any, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of any of the reported shares for purposes of Section 16 or any other purpose. Shares held directly by Westlake BioPartners Fund II, L.P. ("Fund II"). The general partner of Fund II is Westlake BioPartners GP II, LLC ("GP II"). GP II may be deemed to share voting and dispositive power with regard to the shares held directly by Fund II. Seidenberg is the sole managing director of GP II and has voting and dispositive power over the shares held by Fund II. Seidenberg disclaims Section 16 beneficial ownership of the shares reported herein except to the extent of her pecuniary interest therein, if any, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of any of the reported shares for purposes of Section 16 or any other purpose. Reflects a convertible note that was convertible into shares of Common Stock of the Issuer. The convertible note had a maturity date of June 17, 2027. The principal amount of the convertible note together with any accrued but unpaid interest automatically converted into shares of Common Stock of the Issuer upon the closing of the Issuer's initial public offering at a conversion price equal to the initial public offering price of the Issuer's common stock. Shares held directly by Westlake BioPartners Opportunity Fund I, L.P. ("Opportunity Fund"). The general partner of Opportunity Fund is Westlake BioPartners Opportunity GP I, LLC ("Opportunity GP"). Opportunity GP may be deemed to share voting and dispositive power with regard to the shares held directly by Opportunity Fund. Seidenberg is the sole managing director of Opportunity GP and has voting and dispositive power over the shares held by Opportunity Fund. Seidenberg disclaims Section 16 beneficial ownership of the shares reported herein except to the extent of her pecuniary interest therein, if any, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of any of the reported shares for purposes of Section 16 or any other purpose. By: /s/ Jennifer L. Kercher, as Attorney-in-Fact 2026-08-10