BioAtla Investor Presentation Deck

Liposarcoma and Synovial sarcoma: Phase 2 Progression Free Survival Progress-Free Survival Probability Number at Risk BA3011 ■ 1.0- ■ 0.8 0.6 0.4- 0.2 0.0 0 6 4 Liposarcoma BA3011 1.8mg/kg Q2W n=6 TmPS>=70 2 3 3 3 Events n(%) 4 (66.7) Median (mos) (95% CI) 4.6 (0.2 - 6.4) 4 Months from First Dose 3 5 1 6 1 PFS 3mo % (95% CI) 60.0 (12.6, 88.2) 7 0 8 Progress-Free Survival Probability Number at Risk BA3011 1.0 0.8 0.6 0.4- 0.2- 0.0 0 5 1 4 Synovial Sarcoma BA3011 1.8mg/kg Q2W n=5 Events n(%) TmPS>=70 3(60.0) 2 3 Median (mos) (95% CI) 3.5 (1.1-4.7) 3 Months from First Dose 1 4 1 5 0 PFS 3mo % (95% CI) 50.0 (5.8, 84.5) 6 Phase 2 PFS rate at 3 months of 60% for liposarcoma and 50% for synovial sarcoma BA3011 monotherapy in patients with 3 or more prior systemic therapies Interim results satisfied the pre-defined Go criteria of liposarcoma and synovial sarcoma cohorts into part 2 of the Phase 2 study. bicatla Next steps under evaluation. BioAtla| Overview Interim data- Data cut-off of Jul 25, 2022 14

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