BioAtla Results Presentation Deck

Undifferentiated Pleomorphic Sarcoma (UPS): Phase 1 & 2 (1.8mg/kg; n=8) Change in Target Lesion and Progression Free Survival 100 80 60 40 20 0 -20 -40 -60 -80 -100 Baseline PHASE 1/2 - UPS Change Target Lesion From Baseline (%) Week 6 Week 20 Week 12 Interim data- Data cut-off of April 28, 2022 Week 28 Combo Week 36 Week 44 Week 52 Week 60 Week 68 Week 76 Week 84 Week 92 Week 100 Progression Free Survival Probability Number at Risk All Patients 0.8 0.6 0.4- 0.2 0.0- 0 T 1 2 3 Progression-free Survival Events n(%) 5(62.5) 4 8 8 7 3 3 All Patients 5 3 T 6 7 8 9 10 11 12 13 Months from First Dose 3 3 2 2 2 1 1 1 Mecbotamab vedotin - BA3011 Median (mos) (95% CI) 6.8 (1.4-NE) 14 15 16 bicatla 1 1 1 17 18 PFS 3mo % (95% CI) 50.0 (15.2, 77.5) 19 20 21 1 1 0 5

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