BioAtla Investor Presentation Deck

Phase 1/2 trial design for CAB-CTLA-4 Naked Antibody (BA3071) in tumors known to be responsive to CTLA-4 treatment FPI 3Q 2022 BA3071 7 mg Q3W (n=1-6) BA3071 21 mg Q3W (n=1-6) BA3071 70 mg Q3W* (n=1-6) BA3071 monotherapy Objectives (DLT period) BA3071 210 mg Q3W (n=3-6) ✓ I BA3071 in combination with nivolumab ■ BA3071 350 mg Q3W (n-3-6) BA3071 700 mg Q3W (n-3-6) RP2D selection bicatla *Dose equivalent to approved ipilimumab dose (1 mg/kg); Status as of May 4, 2023 Phase 2 Expansion in 2H 2023 Select Up to Two for Potential Phase 2 Dose Expansion Cohorts RCC n=40 Melanoma n=40 NSCLC n=40 SCLC n=40 Bladder n=40 ■ Determine Phase 2 dose and MTD Characterize safety and clinical activity of BA3071 monotherapy and in combination with a PD-1 inhibitor (Nivolumab) Characterize PK, ADA and biomarkers Gastric n=40 aHCC n=40 Cervical n=40 BioAtla | Overview 37

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