BioAtla IPO Presentation Deck

BA3071: Equivalent Results and Enhanced Safety in Preclinical Models Results in human CTLA-4 engineered mouse model 4000 Isotype control (0/8 CR) Ipi-Analogue (1/8 CR) 3000- BA3071 (2/8 CR) *** Tumor volume (mm) 2000- 1000- Nivo +Ipi Positive Control Animal # #1 Vehicle Control #3 Nivo CAB-BA3071 #2 2 Combination I/O Non-Human Primate Toxicity Study Results Study date #4 #5 10 Study Day #1 or #2 02 #3 #4 #5 #1 #2 # 3 #4 # 5 15 20 Primate dosing levels (Nivo + Ipi) and (Nivo + BA3071): • PD-1 = 20mg/kg QW . CTLA-4= 15mg/kg QW bicatla Primate dosing ratio Compared to std. human dose • PD-1 dosed at 12x . CTLA-4 dosed at 45 - 60x 1 Despite high doses, Nivo + CAB-BA3071 demonstrates impressive safety results, especially compared to Nivo + Ipi BA3071 demonstrates similar results to Ipi, but exhibits more selective targeting, which is associated with fewer toxicities 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 GI Symptoms Liquid feces Non-formed feces Other Gl symptoms Chart reflects once weekly exposure 23

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