X0306 4 2022-03-17 1 0001808865 iTeos Therapeutics, Inc. ITOS 0001465837 Boxer Capital, LLC 12860 EL CAMINO REAL, SUITE 300 SAN DIEGO CA 92130 0 0 1 0 0001465836 Boxer Asset Management Inc. C/O CAY HOUSE EP TAYLOR DRIVE N7776, LYFORD CAY NEW PROVIDENCE, C5 BAHAMAS 0 0 1 0 0001015747 LEWIS JOSEPH C/O CAY HOUSE EP TAYLOR DRIVE N7776, LYFORD CAY NEW PROVIDENCE C5 BAHAMAS 0 0 1 0 Common Stock 2022-03-17 4 S 0 575201 35.25 D 3142058 D These securities are owned directly by Boxer Capital, LLC ("Boxer Capital"), which may be deemed to be a member of a "group" for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, consisting of (i) Boxer Capital, (ii) Boxer Asset Management Inc. ("Boxer Management"), (iii) Aaron I. Davis, and (iv) Joseph C. Lewis (collectively, the "Boxer Group"). These securities are owned indirectly by Boxer Management and Joseph C. Lewis, by virtue of their ownership of Boxer Capital. Each member of the Boxer Group other than Boxer Capital disclaims beneficial ownership of these securities to the extent it or he does not have a pecuniary interest therein. Boxer Capital, LLC, By: /s/ Aaron I. Davis, Aaron I. Davis 2022-03-18 Boxer Asset Management Inc., By: /s/ Jason Callender, Jason Callender 2022-03-18 Joseph C. Lewis, /s/ Joseph C. Lewis, Joseph C. Lewis 2022-03-18