BioAtla Investor Presentation Deck

Continued promising safety and tolerability profile in Sarcoma Phase 2 at the RP2D 1.8 mg/kg Q2W Characteristic Any Adverse Events (AES) Related AEs with CTCAE¹ Grade 3 or 4² Any related serious AEs² Related AEs leading to death² Related AEs leading to treatment discontinuation² bicatla Constipation Peripheral Neuropathy BA3011 (N=63) 60 (95%) 17 (27%) 5 (8%) Diarrhea 0 3 (5%)§ BA3011+ Nivoumab Grade 1-2 (19%) Grade 3 (1%) All Grade 1-2 (19%) (N=26) 24 (92%) 8 (30%) 4 (15%) 0 1 (4%)^ ■ ■ No treatment-related deaths I Few treatment-related SAESs, consistent with MMAE-based toxicity, including reversible myelosuppression, transient liver enzyme elevation, metabolic disturbances Very few related AEs leading to treatment discontinuation Grade 3-4 (0%) Grade 1-2 (19%) Grade 3-4 (0%) Low-grade constipation observed is consistent with baseline levels seen in advanced cancer patients Interim data- Data cut-off of Oct 17, 2022 Note: ¹CTCAE: Common Terminology Criteria for Adverse Events. The NCI Common Terminology Criteria for Adverse Events is a descriptive terminology which is utilized for Adverse Event (AE) reporting. A grading (severity) scale is provided for each AE term. 2As assessed by the investigator. Missing responses are counted as related. Con Grade 2 peripheral neuropathy; pancreatitis; ^grade 2 lleus No clinically meaningful on-target toxicity observed over background Differentiated profile due to avoiding on-target off-tumor toxicity BioAtla| Overview 13

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