BioAtla Investor Presentation Deck

BA3182 - CAB-EpCAM x CAB-CD3 Bispecific T-Cell Engager (TCE) Significant opportunity for safe and effective EpCAM x CD3 bispecific EpCAM expressed on normal epithelial cells and overexpressed in a wide range of tumors (adenocarcinoma) CD3-bispecifics have demonstrated beneficial effects but hampered by dose-limiting toxicity, namely, cytokine release syndrome (CRS) 2500 Tumor volume (mm³) bicatla 2000 1500 1000 500 0 0 Tumor shrinkage Isotype x WT CD3 -EpCAM x WT CD3 ACAB EpCAM x CAB CD3 10 20 30 40 Study Days MiXeno Model with HCT116= Colorectal Cancer Cell Line 1mg/kg twice/week in mice (equivalent to 0.25mg/kg in non-human primates) 50 ● BA3182 exhibits efficient tumor shrinkage with superior safety profile • In non-GLP and GLP tox studies in NHP, dual selection results in high selectivity ► 160-fold TI increase MTD not reached (5mg/kg highest dose studied=NOAEL) No Cytokine release observed or other EpCAM or CD3 known related toxicities Safety Profile WT-EpCAM x WT-CD3 *0.025mg/kg = 2 ill *0.05 mg/kg = 2 expired *Single Dose non-GLP Toxicity Study WT = wild type; *from independent experiments MTD Maximum Tolerated Dose TI = Therapeutic Index CAB-EpCAM x CAB-CD3 (BA3182) *0.25mg/kg = 2 normal *1.0 mg/kg = 2 normal *2.5 mg/kg = 2 normal *2.5 mg/kg = 10 normal *5.0 mg/kg 10 normal *QW x 4 weeks - GLP Toxicity Study = BioAtla | Overview 33

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