BioAtla Investor Presentation Deck

Potential market opportunity in sarcoma 2nd most common Soft Tissue Sarcoma (STS) subtype (~15% of all STS)¹ UPS Other Subtypes bicatla 1 2 3 High-grade aggressive subtype with high recurrence rates¹ 3k 4k AXL+ addressable patients per year in the U.S.1,2 - Chemotherapy, chemoradiation or regional limb therapy for unresectable cases No approved targeted therapies for UPS Approved treatments for sarcoma ORR ~15%³ 1 Osteosarcoma - most common malignant primary bone tumor (30% of all such malignancies)4 2 Liposarcoma - one of the largest soft tissue sarcoma subtypes (15% - 20% of all STS)5 3 Synovial sarcoma - smaller subtype, but high recurrence rate (~50% of patients) 4 Limited effective treatment options across all sarcoma subtypes Current Treatments 1¹Undifferentiated Pleomorphic Sarcoma - StatPearls - NCBI Bookshelf (nih.gov); Annals of Oncology 30: 1143-1153, 2019; ²Company estimates; ³Product USPIs; 4https://www.cancernetwork.com/view/bone-sarcomas. 5https://rarediseases.org/rare-diseases/liposarcoma/; "https://www.sciencedirect.com/science/article/pii/S0923753419386727 ORR, objective response rate (best objective response as confirmed complete response or partial response); STS, soft tissue sarcoma; UPS, undifferentiated pleomorphic sarcoma. BioAtla| Overview 9

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