#1Conditionally Active Biologics: Transforming Cancer Therapy Jefferies Global Healthcare Conference June 2022 bicatla ހރހހހހހހ އކނއކމކރތކއ ރތކމކlއgހނހރރީ އޗކޗރޓަރދީ ޗކ ދއކމކ އހރވ ހހހހހހހ އދަރީ' ކޓަރ) އރގއި އ ކހހހހëހ ޓހf#2Important Notices & Disclaimers This presentation (the "Presentation") by BioAtla, Inc. ("we", "us", "our", "BioAtla", or the "Company") contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 relating to our business, operations and financial conditions, including but not limited to current beliefs, expectations and assumptions regarding the future of our business, future plans and strategies, results of clinical trials and other future conditions. Words such as, but not limited to, "anticipate", "believe", "could", "estimate", "expect", "intend", "may", "plan", "potential", "predict", "project", "should", "will", "would" or the negative of those terms, and similar expressions that convey uncertainty of future events or outcomes, identify forward-looking statements. These forward-looking statements reflect management's beliefs and views with respect to future events and are based on estimates and assumptions as of the date of this Presentation and are subject to risks and uncertainties, including those described in the Company's filings with the SEC, including but not limited to the Company's latest Annual Report on Form 10-K. Moreover, the Company operates in a very competitive and rapidly changing environment. New risks emerge from time to time. It is not possible for management to predict all risks, nor can the Company assess the impact of all factors on its business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. Given these uncertainties, you should not place undue reliance on these forward-looking statements. The Company qualifies all the forward-looking statements in this Presentation by these cautionary statements. Except as required by law, the Company undertakes no obligation to publicly update any forward-looking statements, whether as a result of new information, future events or otherwise. Statements contained herein are made as of the date of this Presentation unless stated otherwise, and this Presentation shall not under any circumstances create an implication that the information contained herein is correct as of any time after such date or that the information will be updated or revisited to reflect information that subsequently becomes available or changes occurring after that date hereof. Certain information contained in this Presentation relates to or is based on statistical and other industry and market data obtained from independent industry publications and research, surveys and studies conducted by independent third parties as well as the Company's own estimates of the prevalence of certain diseases and conditions. The market data used in this Presentation involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such data. Industry publications and third-party research, surveys and studies generally indicate that their information has been obtained from sources believed to be reliable, although they do not guarantee the accuracy or completeness of such information. The Company's estimates of the patient population with the potential to benefit from treatment with any product candidates the Company may develop include several key assumptions based on its industry knowledge, industry publications and third-party research, which may be based on a small sample size and may fail to accurately reflect the addressable patient population. While the Company believes that its internal assumptions are reasonable, no independent source has verified such assumptions. This Presentation may contain trademarks, trade names, or service marks belonging to other entities. The Company does not intend the use or display of other parties' trade names, trademarks or service marks to imply a relationship with, or endorsement or sponsorship of, or by these other parties. None of the Company or any of its directors, officers, employees, contractors, agents, consultants, advisors or other representatives makes any representation or warranty, express or implied, as to the accuracy or completeness of the information contained in this Presentation. bicatla BioAtla Overview | Company Confidential 2#3BioAtla® is a clinical stage company focused on transforming cancer therapy with Conditionally Active Biologics (CABs) ● Proprietary technology Broad applicability Spans multiple tumors bicatla ● Two lead CAB-ADC assets in Phase 2 Interim Phase 2 data w/ 3011 supports advancing in multiple sarcoma indications Near-term catalysts ● Diversified and robust pipeline Strategic optionality ● ● ● Strong cash position $219.4MM (at end 1Q22) with runway into 2H24 Sufficient through key clinical milestones BioAtla Overview | Company Confidential 3#4Selective and targeted CAB technology widens therapeutic index, thus has the potential to enhance clinical outcomes in multiple tumor types المدم BioAtla discovered that acidic pH at the cancer cell surface unveils binding sites that are shielded at normal pH of healthy cells BioAtla invented CAB technology, creating antibodies that bind only to these unveiled sites on cancer cells CAB binding region is not masked or caged and thus different from prodrugs that require irreversible enzymatic cleavage to become activated CAB antibodies have the potential for increased efficacy with improved safety relative to traditional antibodies bicatla Alkaline Healthy Cell Membrane Glycocalyx Basic pH HEALTHY CELL FAVOR Intracellular Mildly Acidic pH No CAB Binding H+ H H+ CAMERASER Acidic Cancer Cell Membrane CANCER CELL Intracellular Mildly Basic pH. CAB Binding H+ H+ H* H+ H Glycocalyx Acidic pH H+ H+ CUTORI Chang, H.W., Frey, G., Liu, H., Xing, C., Steinman, L, Boyle, B.J., & Short, J.M. (2021) PNAS 118(9): 1-10, Suppl. 1-19. BioAtla Overview | Company Confidential 4#5Focused pipeline with broad applicability of differentiated CAB assets designed to deliver near-term value CAB-ADCs CAB-I/O CAB-Bi- specifics CAB Program BA3011 Mecbotamab Vedotin BA3021 Ozuriftamab Vedotin BA3071 BA3182 Additional programs Target AXL ROR2 CTLA-4 EpCAM & CD3 Various ● ● ● ● Indications STS & Bone Sarcoma NSCLC Ovarian Cancer* NSCLC Melanoma SCCHN Ovarian Cancer* Mutiple tumor types** Adenocarcinoma** Multiple tumor types** Multiple tumor types** IND Enabling Pre-Clinical * Phase 2 investigator-initiated trial for Ovarian Cancer ** Indications based upon tumor target expression bicatla Phase 1 Clinical Phase 2 Clinical IIT, investigator-initiated trial; IND, investigational new drug; NSCLC, Non-small Cell Lung Cancer; RCC, Renal Cell Carcinoma; SCCHN, Squamous Cell Carcinoma of the Head and Neck; STS, Soft Tissue Sarcoma. Anticipated Milestones ✓ Interim sarcoma update Q1 earnings Phase 2 interim NSCLC clinical data Q2 earnings Ovarian IIT dosing 1H22 Phase 2 interim NSCLC and melanoma data mid-year / 2H22 SCCHN trial dosing 1H22 ✓ Ovarian IIT dosing 1H22 Trial dosing 1H22 IND submission and Phase 1 initiation 2022 2023 and beyond BioAtla Overview | Company Confidential 5#6Sarcoma Cells bicatla CAB-AXL-ADC Platform BA3011 Mecbotamab Vedotin: Sarcoma and NSCLC#7Significant opportunity for BA3011 in Sarcoma and NSCLC to fill unmet medical needs ++ bicatla Current treatments for AXL+ tumors are insufficient, leading to high recurrence rates, rapid progression, low survival rates, and drug-related toxicities Our Phase 1 studies revealed positive clinical signals across sarcoma and NSCLC, demonstrated by durable clinical responses (PFS and PR), and reductions in tumor size We have two ongoing Phase 2 studies in sarcoma and NSCLC We are excited to advance towards our transition to commercial-stage company while filling a significant unmet medical need for patients with AXL+ solid tumors NSCLC, non-small cell lung cancer; PFS, progression-free survival; PR, partial response. BioAtla Overview | Company Confidential 7#8Sarcoma: Encouraging Phase 2 Part 1 Topline Interim Analysis Results BA3011 Monotherapy (n=105) Combination with PD-1 (n=20) bicatla Phase 2 PART 1 STS Bone CD20 (BA3011 + Opdivo) Leiomyosarcoma (n=17)* Synovial sarcoma (n=3)* Liposarcoma (n=4)* Other Soft Tissue / UPS (n=8 / 5)* Osteosarcoma (n=6)* Ewing sarcoma (n=0)* Others (chondro/chordo) (n=7 [4 / 3])* Positive (n=14)* Negative (n=4)* Interim Results Leiomyosarcoma not moving forward; PFS rate 27% (pending confirmation) Pending Pending UPS moving forward; PR = 2/6 Osteosarcoma moving forward; PFS rate 67% Pending Pending Combo w PD-1 moving forward; PR = 1/1 (UPS)**; PFS rate (combo overall) 51% All other cohorts (in gray) – continue enrollment BA3011 - Mecbotamab vedotin Pre-defined criteria for each subgroup up to 10 patients: 'No Go' if 0 CR/PR and PFS rate at 12 weeks <40%; 'Go' if ≥1 CR/PR or PFS rate at 12 weeks >40%. * As of data cut-off of Apr 28, 2022; Cohorts in grey continuing enrollment until sufficient sample size is achieved. **Included in UPS cohort. BA3011 dose 1.8 mg/kg Q2W. Inclusion criteria: measurable disease, ECOG performance status 0 or 1. PFS, progression-free survival; PR, partial response; UPS, undifferentiated pleomorphic sarcoma. Interim results satisfied pre-defined 'Go' criteria into part 2 of the Phase 2 BA3011 study in both UPS and Osteosarcoma BioAtla Overview | Company Confidential 8#9Continued promising safety and tolerability profile observed in Phase 2 at the RP2D [en No treatment- related deaths bicatla Few treatment-related SAES, consistent with MMAE-based toxicity, including: Reversible myelosuppression, Transient liver enzyme elevation, Metabolic disturbances Company material-confidential 808 Few related AEs leading to treatment discontinuation + No clinically meaningful on-target toxicity observed over background BA3011 - Mecbotamab vedotin Differentiated profile due to avoiding on- target off-tumor toxicity BioAtla Overview | Company Confidential 9#10Encouraging Phase 1 results enables initiation of Phase 2 study in NSCLC Phase 2 study and enrollment in refractory NSCLC patients: bicatla ● A partial response was achieved in the AXL-high NSCLC patient refractory to multiple chemo PKIs and pembrolizumab failure Initial interim analysis ● ● ● AXL+ ≥1 TmPS Monotherapy and Combination with PD-1/L1 After ~20 pts complete 2 scans Next step ● ● If definitive, move into part 2 or stop program Ability to continue enrollment up to ~40 patients, if desired Phase 2 part 2 ● ● ● Combination (BA3011+Opdivo) Monotherapy (BA3011) n=100 per arm Endpoints Primary endpoints ● ● BA3011 - Mecbotamab vedotin ● Confirmed ORR per RECIST v1.1 AES or SAEs Secondary endpoints DOR, PFS, ORR, DCR, TTR, OS BA3011 dose 1.8 mg/kg Q2W. Inclusion criteria: measurable disease, ≥ 18 years, ECOG performance status 0 or 1. AE, adverse event; BOR, best overall response; DCR, disease control rate; DOR, duration of response; ORR, objective response rate; OS, overall survival; PFS, progression-free survival; SAE, serious adverse event; TTR, time to response. BioAtla Overview | Company Confidential 10#11bicatla CAB-ROR2-ADC Platform BA3021 Ozuriftamab Vedotin - NSCLC and Melanoma#12Encouraging Phase 1 results with BA3021 support advancing into Phase 2 in multiple indications No ROR2 ADC or small molecules in the clinic to date, suggesting CAB-ROR2-ADC is potentially a first-in- class therapy across multiple tumor types bicatla *ROR2+ patients who received Ph2 dose or higher ● ● BA3021 - Ozuriftamab vedotin Phase 1 study NSCLC: PR (n= 2/ 3* ROR2+) Melanoma: CR (n= 1 / 1 ROR2+) - clearance of pulmonary metastases followed by normalization of adenopathy and continued CR off treatment for over 2 years SCCHN: PR (n= 1 / 1 ROR2+ PD-1/cetuximab refractory patient) Promising safety and tolerability profile across multiple tumor types Phase 2 studies NSCLC ROR2+ patients w/ TmPS ≥1%; refractory to PD-1, EGFR, or ALK; mono & combination w/ PD-1; sample size n=40 Melanoma ROR2+ patients w/ TmPS ≥1%; refractory to PD-1; mono & combination w/ PD-1; sample size n=40 CR (n=1 / 1) on 1st scan, 3 doses SC OR2+ patients w/ TmPS ≥1%; refractory to PD-1 alone or in combination with platinum; mono & combination w/ PD-1; sample size n=40 BioAtla Overview | Company Confidential 12#13A number of key upcoming milestones in 2022 Program BA3011 Mecbotamab Vedotin BA3021 Ozuriftamab Vedotin BA3071 BA3182 bicatla CAB-ADCs Indications STS and bone sarcoma NSCLC Ovarian* NSCLC Melanoma SCCHN Ovarian* Multiple tumor types** Adenocarcinoma** Multiple tumor types** CAB-I/O CAB-Bispecifics 1H 2022 Phase 2 interim update Phase 2 interim data ✓ Phase 2 IIT dosing Phase 2 dosing Phase 2 IIT dosing Phase 1/2 dosing *Phase 2 Investigator-initiated trial combination with PD-1 (n=60) in platinum failure patients. Initial sites activated. **Anticipated indications based upon tumor target expression. 2H Phase 2 part 2 initiation Phase 2 interim data ☆ Phase 2 interim data IND submission / Phase 1 initiation BioAtla Overview | Company Confidential 13#14BioAtla® is a clinical stage company focused on transforming cancer therapy with Conditionally Active Biologics (CABS) ● Proprietary technology Broad applicability Spans multiple tumors bicatla Execute on clinical programs ● ● Two lead CAB-ADC assets in Phase 2 Interim Phase 2 data w/ 3011 supports advancing in multiple sarcoma indications Near-term catalysts ● ● Diversified and robust pipeline Strategic optionality Create long-term sustainable value ● ● Strong cash position $219.4MM (at end 1Q22) with runway into 2H24 Sufficient through key clinical milestones Build core commercial capabilities BioAtla Overview | Company Confidential 14#15Conditionally Active Biologics: Transforming Cancer Therapy Jefferies Global Healthcare Conference June 2022 bicatla ހރހހހހހހ އކނއކމކރތކއ ރތކމކlއgހނހރރީ އޗކޗރޓަރދީ ޗކ ދއކމކ އހރވ ހހހހހހހ އދަރީ' ކޓަރ) އރގއި އ ކހހހހëހ ޓހf