BioAtla Investor Presentation Deck

BA3071 (CAB-CTLA-4) Best-in-class and potential for disruption of the I/O Market Research demonstrates challenges and opportunity in combining two Immune Checkpoint Inhibitors* I - Improves efficacy, but increases adverse events Greater % of patients discontinue therapy relative to monotherapy In NHP study, BA3071 achieved similar exposure levels to Ipi analog with significantly less toxicity in combination with nivo** bicatla Clinical Endpoint Progression Free Survival Grade 3 or 4 Adverse Events Discontinued Treatment Vehicle Control Nivo + Ipi Positive Control Nivo + CAB- BA3071 #1 #2 #3 #4 #5 #1 #2 #3 ###### Study date 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Cvno # #4 #1 or #2 #5 #1 #2 #3 #4 *Larkin et al., New Eng. J. Med.,373: 23-34, 2015 **Chang et al., PNAS 118 (9): 1-10, 2021 Nivo: 20mg/kg QW (12X human dose); Ipi or CAB-CTLA: 15mg/kg QW (45-60X human dose) Once weekly for four weeks exposure to Nivo + Ipi or CAB CTLA4 AUC168 = Area under the serum drug concentration-time curve from time zero to 168 hours; Cmax = Highest drug concentration observed in serum #5 Nivolumab (PD-1) ●●● 6.9 months 16.3% 7.7% Nivolumab (PD-1) + Ipilimumab (CTLA4) 11.5 months 55.0% 36.4% GI Symptoms A Liquid feces Non-formed feces Other Gl symptoms BioAtla| Overview 30

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