Kymera Investor Presentation Deck

% Change from C1D1 Predose (Mean ± SEM) Strong Proof-of-mechanism for KT-333 with up to 88% Mean Maximum Nearing Desired Degradation Profile at DL3 -20 WA Cycle 1 weeks 1 & 2 T T T T T T 9 10 11 12 29 30 31 32 33 34 35 36 37 38 -40 -60 -80- -100 KT-333 ● ● Method: Targeted Mass Spectrometry KYMERA T T 1 2 3 T 4 5 6 7 8 Cycle 2 weeks 1 & 2 ©2023 KYMERA THERAPEUTICS, INC. +++ DL1 DL2 DL3 Dose Level 0.05 mg/kg (n=4) 0.1 mg/kg (n=3) 0.2 mg/kg (n=2) Patient ID 105-001 105-002 102-001 105-003 105-004 103-001 180-004 180-001 180-002 Cycle 1 Maximum Degradation mean** (weekly max) -79.8% (-75.6 %, -84.1 %) -67.8 % (-73.5%, -62.0 %) -50.0 % (-47.4 %, -52.6 %) -67.8% (-66.1 %, -69.5 %) -65.5 % (-65.5 %, missing) -74.4 % (-68.1 %, -80.7%) -70.6 % (-66.9 %, -74.4 %) -75.5% (-73.9 %, -77.0%) -85.4 % (-80.3 %, -90.4 %) ** post doses 1 & 2; # = BLOQ Average -66.4% -70.2% -80.5% Maximum Degradation mean (weekly max) N/A N/A N/A Cycle 2 Days in Study Dose-dependent STAT3 degradation Mean maximum degradation of up to 85.4% in Cycle 1 and 88.4% in Cycle 2 Weekly maximum reductions of up to 90-91% Profile at or nearing STAT3 degradation that has been shown to lead to strong antitumor effects in preclinical models N/A -82.8 % -88.4 % (-91.0# %, -85.7#%) pending -83.6% (-88.6 %, -78.6%) -80.0 % (-72.7%, -87.2%) ** post doses 5 & 6; # = BLOQ ** Average N/A -85.6 % -81.8% As of the data cut-off date of May 1, 2023. PAGE 47

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