#1ތކތކޓރކFކށީނނި ހކއކކޗރޓަހކރކ1 ބދށަގނޑއ ހކރރއހރއނދއނަ އނ އދގެ އދއޖހވރވ ކމއ ދހހހހހށަހދއށައވރވއދއތ ތ، މ.އއާ ނ ހރ ހހހހހހ. non Conditionally Active Biologics: Transforming Cancer Therapy Corporate Presentation August 2022 bicatla#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. 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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 2#3BioAtla® is a clinical stage company focused on transforming cancer therapy with Conditionally Active Biologics (CABS) Proprietary technology Broad applicability in solid tumors Increases therapeutic bicatla window Two Phase 2 CAB-ADCs Interim BA3011 Phase 2 data supports advancing to registration studies in multiple sarcoma and NSCLC indications Diversified pipeline Near-term clinical readouts for multiple indications Strategic optionality Strong cash position $202.3MM (2022) with runway into 2H24 Sufficient through key clinical milestones BioAtla| Overview 3#4Leadership Team Jay Short, Ph.D. Chairman, CEO and Cofounder STRATAGENE DIVERSA HARNESSING THE POWER OF ENZYMES Eric Sievers, M.D. Chief Medical Officer OSeattleGenetics ZYMOGENETICS A Bristol-Myers Squibb Company. bicatla life technologies FRED HUTCH CURES START HERE" Scott Smith, M.S., M.B.A. President Celgene BIOVAIL SYNTHETIC GENOMICS PHARMACIA Cathy Chang, Ph.D. Sr. VP, Research & Development DIVERSA HARNESSING THE POWER OF ENZYMES 1STRATAGENE Richard Waldron, M.B.A. Chief Financial Officer INTREXON GeneMedicine, Inc. COWEN AND COMPANY William Boyle, Ph.D. Sr. Research Fellow AnaptysBio AMGEN salk Where cures begin. Philippe Martin, M.S., M.B.A. Chief of Clinical Dev & Operations Schering-Plough Celgene Aventis Aventis Monica Sullivan Sr. VP, Intellectual Property & Contracts STRATAGENE DIVERSA HARNESSING THE POWER OF ENZYMES CapalP Sheri Lydick Sr. VP, Commercial Strategy Celgenel Bristol Myers Squibb™ ALTANA Susie Melody Sr. VP, Human Resources senomyx Biogen BCG BioAtla | Overview 4#5Selective and targeted CAB technology widens therapeutic window, thus has the potential to enhance clinical outcomes in multiple tumor types సం bicatla 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 Alkaline Healthy Cell Membrane Glycocalyx Basic pH BARZO 2 HEALTHY CELL Intracellular Mildly Acidic pH No CAB Binding H H REMEASE Acidic Cancer Cell Membrane CANCER CELL Intracellular Mildly Basic pH CAB Binding H+ H H H H Glycocalyx Acidic pH H H 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 5#6Broad applicability of BioAtla's CAB platform across several antibody types has the potential to treat multiple solid tumors Targets: AXL, ROR2 ADCs Widely expressed in a variety of tumor types, AXL and ROR2 overexpression correlates with poor prognosis, metastasis, and drug resistance to PD-1 and EGFR therapies CAB-Tumor Cell Target bicatla Cytotoxic payload and linker Naked Antibodies Target: CTLA-4 CTLA-4 blockade activates effector T cells, thereby enhancing anti- tumor immunity CAB-CTLA4 CAB-CTLA4 Target: EpCAM & CD3 Bispecifics Bispecific antibodies bridge cancer cells and cytotoxic T lymphocytes, activating T cells and promoting cancer cell lysis Tumor Cell Target T Cell Target CAB-EPCAM CAB-CD3 BioAtla| Overview 6#7Focused 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 bicatla Target AXL ROR2 CTLA-4 EpCAM & CD3 Various Indications STS & Bone Sarcoma NSCLC Ovarian Cancer* NSCLC Melanoma SCCHN Ovarian Cancer* Multiple tumor types** Adenocarcinoma** Multiple tumor types** Multiple tumor types** IND Enabling Pre-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. Phase 1 Clinical Phase 2 Clinical Anticipated Milestones ✓ Interim sarcoma results - achieved go criteria to advance UPS and osteosarcoma into Phase 2 part 2 Initial interim NSCLC results - achieved go criteria to advance to Phase 2 part 2 ✓ Ovarian IIT dosing Phase 2 interim NSCLC data and melanoma update 2H22 SCCHN trial dosing 3Q ✓ Ovarian IIT dosing ✓ Phase 1 / 2 dosing IND submission and Phase 1 initiation 2H2022 2023 and beyond * Phase 2 investigator-initiated trial for Ovarian Cancer ** Indications based upon tumor target expression BioAtla| Overview 7#8bicatla CAB-AXL-ADC Platform BA3011 Mecbotamab Vedotin: Sarcoma and NSCLC#9Potential market opportunity in UPS and Osteosarcoma 2nd most common Soft Tissue Sarcoma (STS) subtype (~15% of all STS)¹ UPS Osteosarcoma bicatla 1 2 3 1 2 3 High-grade aggressive subtype with high recurrence rates¹ 3k 4k AXL+ addressable patients per year in the U.S.1,4 Most common malignant primary bone tumor (30% of all such malignancies)² ~20% of patients have metastases at diagnosis; of the remainder, 50% progress to clinical metastasis³ 2k 3k AXL+ addressable patients per year in the U.S.2-4 - - - - Chemotherapy, chemoradiation or regional limb therapy for unresectable cases No approved targeted therapies for UPS Approved treatments for sarcoma ORR ~15%5 Current Treatments ¹Undifferentiated Pleomorphic Sarcoma - StatPearls - NCBI Bookshelf (nih.gov); Annals of Oncology 30: 1143-1153, 2019. ²https://www.cancernetwork.com/view/bone-sarcomas. 3https://www.cancer.org/cancer/osteosarcoma/detection-diagnosis-staging/staging.html; 1st-line surgical resection +/- chemo / radiation No approved therapies for 2L+ Independent Phase 2 study showed PFS rate for placebo at 8 weeks = ~0%6 https://www.texasoncology.com/types-of-cancer/bone-cancer/osteosarcoma- overview/recurrent-osteosarcoma. 4Company estimates 5Product USPIs. "Lancel Oncol 2019 Jan;20(1):120-133. 2L, second line; 2L+, second line or greater; ORR, objective response rate (best objective response as confirmed complete response or partial response); PBO, placebo; STS, soft tissue sarcoma; UPS, undifferentiated pleomorphic sarcoma. Current Treatments BioAtla| Overview 9#10Encouraging Phase 1 results with Mecbotamab Vedotin (BA3011) in refractory sarcoma ■ Confirmed TmPS* ≥70; 1.8mg/kg Q3W or 2Q3W Maximum % Change from Baseline in Sum of Target Lesions 100 80 60 40 20 -20 -40 -60 -80 -100 AXL+ TmPS-90$ bicatla 1.8mg/kg d1,8 Leiomyosarcoma (LMS) AXL+ TmPS=100 1.8mg/kg d1,8 Synovial² Sarcoma AXL+ TmPS=100 1.8mg/kg d1,8 Uterine LMS r Confirmed Partial Response (PR) AXL+ TmPS-90 1.8mg/kg LMS * (NED¹) AXL+ TmPS-95 1.8mg/kg d1,8 UPS AXL+ TmPS-70 1.8mg/kg d1,8 UPS AXL+ TmPS=100 1.8mg/kg Ewing I Change in Target Lesion from Baseline (%) Evaluable Patients in Phase 1 at All Doses 100 80 60 40 20 -20 -40 -60 -80 -100 0 10 Notes: All patients: Multiple cycles of antineoplastic agents received prior to starting treatment with BA3011 *AXL Tumor membrane Percent Score or TmPS = % Score 21+; $Tissue biopsy from resection, over 1 year old prior to trial entry 1 NED = No evidence of disease; 2 Synovial sarcoma patient delayed treatment due to unrelated SAE led to progression 20 = PR was achieved in 4/7 high TmPS patients receiving the clinically-meaningful 1.8 mg/kg dose Antitumor activity correlates with higher levels of AXL tumor membrane expression in sarcoma patients 30 High TmPS ≥70 Low TmPS ≤70 or Not Evaluable 40 Time (weeks) 50 60 70 BioAtla| Overview 10#11Phase 2 Part 1 Topline Interim Analysis Results Confirm Phase 1 Signal following BA3011 in refractory sarcoma subtypes BA3011 Monotherapy (n=105) Combination with PD-1 (n=20) bicatla Phase 2 Part 1 STS Bone CD20 (BA3011 + Opdivo) Leiomyosarcoma (n=18)* Synovial sarcoma (n=5)* Liposarcoma (n=6)* Other Soft Tissue / UPS (n=17/8)* Osteosarcoma (n=6)* Ewing sarcoma (n=2)* Others (chondro/chordo) (n=8 [5/ 3])* CD 20 Positive (n=14)* CD 20 Negative (n=10)* Interim Results Leiomyosarcoma; PFS rate 12W 32% Synovial PFS rate 12W 50% Liposarcoma PFS rate 12W 60% UPS PR = 2/6 Osteosarcoma; PFS rate 12W 67% Ewing sarcoma Pending Others (chondro/chordo) Pending Combo w/ PD-1; PR = 1/1 (UPS)** & PFS rate 12W (combo overall) 40% Combo w/ PD-1, CD 20-; PFS rate 12W 16.7% Cohorts in gray continue to interim read-out Advance P2 Part 2 Hold Evaluating Evaluating Go Go III Hold No Go Pre-defined criteria for each subgroup up to 10 patients: 'No Go' if 0 CR/PR and PFS rate at 3 months <40%; 'Go' if ≥1 CR/PR or PFS rate at 3 months >40%. * As of data cut-off Jul 25, 2022; Cohorts in gray continuing enrollment until sufficient sample size is achieved. **Included in UPS cohort. BA3011 dose 1.8 mg/kg Q2W. 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 multiple sarcoma subtypes: UPS and osteosarcoma advancing as separate cohorts to potentially registration studies (Phase 2 part 2). Additional detail for part 2 ● ■ will become available following FDA written response Liposarcoma and synovial sarcoma next steps under evaluation BioAtla| Overview 11#12Undifferentiated Pleomorphic Sarcoma (UPS): Phase 1 & 2 Change in Target Lesion and Progression Free Survival (1.8mg/kg; n=8) -20 -40 -60 -80 -100 100 80 60 40 20 Baseline ■ ■ Week 6 ■ Change Target Lesion From Baseline (%) Week 12 Week 20 Week 28 Combo Week 36 Week 44 Week 52 Week 60 Interim data- Data cut-off of April 28, 2022 Week 84 Week 92 Week 68 Week 76 Week 100 Progression Free Survival Probability Number at Risk 1.0 0.8 0.6 0.4 0.2 0.0 0 All Patient 8 T 1 8 T 2 7 T 3 3 T 4 3 Progression-free Survival All Patients T 5 3 6 T 7 Events n(%) 5(62.5) Median (mos) (95% CI) 6.8 (1.4 - NE) T 8 9 10 11 12 13 14 Months from First Dose 3 3 2 2 2 1 1 1 1 15 4/8 patients achieved PRs, with an ORR of 50% and PFS rate at 3 months of 50% Responses to BA3011 treatment are durable, with partial responders remaining on treatment for extended periods of time Interim results satisfied the pre-defined Go criteria of UPS cohort into part 2 of the Phase 2 study bicatla 1 16 1 T 17 1 PFS 3mo % (95% CI) 50.0 (15.2, 77.5) 18 T 19 1 1 1. T 20 21 0 n/a BioAtla| Overview 12#13Osteosarcoma: Phase 1 & 2 Change in Target Lesion and Progression Free Survival (1.8mg/kg; n=7) 50 40 30 20 10 0 -10 -20 -30 -40 -50 Week 0 Change in target lesion from baseline (%) ■ week 6 week 12 week 18 week 24 Progression Free Survival Probability Number at Risk 1.0- 0.8 Interim data- Data cut-off of April 28, 2022 Recent independent phase 2 study demonstrated placebo PFS rate at 2 months for 1st and 2nd line metastatic osteosarcoma of ~0% (www.thelancet.com/oncology Vol 20 January 2019) 0.6 0.4 0.2- 0.0- All Patients 0 7 Progression-free Survival 7 All Patients 2 3 4 Events n(%) 4(57.1) 4 Median (mos) (95% CI) 3.8 (1.2 - NE) 5 Of 7 patients enrolled, PFS rate at 3 months was 57% When combining all Phase 1 & 2 bone sarcoma patients, a total of 7 patients were enrolled and observed a PFS rate at 3 months of 56% Interim results satisfied the pre-defined Go criteria of osteosarcoma cohort into part 2 of the Phase 2 study bicatla Months from First Dose 2 1 6 1 PFS 3mo % (95%CI) 57.1 (17.2, 83.7) 1 7 8 0 BioAtla| Overview 13#14Liposarcoma 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#15Continued promising safety and tolerability profile in Sarcoma Phase 2 at the RP2D 1.8 mg/kg Q2W Characteristic Any Adverse Events (AES) Related AEs with CTCAE¹ Grade 3 or 4² Any related serious AEs² Related AEs leading to death² Related AEs leading to treatment discontinuation² bicatla Constipation Peripheral Neuropathy Diarrhea BA3011 (N=71) 64 (90%) 17 (24%) 6 (8%) 0 2 (3%) § Grade 1-2 (19%) Grade 3-4 (0%) All Grade 1-2 (21%) Grade 1-2 (19%) Grade 3-4 (0%) Low-grade constipation observed is consistent with baseline levels seen in advanced cancer patients ■ ■ I No treatment-related deaths Few treatment-related SAESs, consistent with MMAE-based toxicity, including reversible myelosuppression, transient liver enzyme elevation, metabolic disturbances Very few related AEs leading to treatment discontinuation No clinically meaningful on-target toxicity observed over background Differentiated profile due to avoiding on-target off-tumor toxicity Interim data- Data cut-off of May 16, 2022 Note: ¹CTCAE: Common Terminology Criteria for Adverse Events. The NCI Common Terminology Criteria for Adverse Events is a descriptive terminology which is utilized for Adverse Event (AE) reporting. A grading (severity) scale is provided for each AE term. 2As assessed by the investigator. Missing responses are counted as related. §Grade 2 peripheral neuropathytial BioAtla| Overview 15#16Potential market opportunity in metastatic NSCLC ● >540K 2L+ people in the U.S. living with lung cancer¹ bicatla despite advances in 1L care, majority of patients progress³ ~200K ~75% newly diagnosed patients / year (U.S.) - majority advanced / metastatic² non-squamous cell represents majority of patients4 Available Treatment: 1L: Chemo + ICI 50% ORR5 2L+: SOC 10% - 20% ORR6,7 Target population: ~50K AXL+ addressable 2L+ patients/year in the U.S.8, based on AXL positivity rate of ~35% Internal success threshold: 2L+ ORR of ~15% - 20% (approvability bar); 20%+ (commercially relevant) following BA3011 monotherapy ¹https://www.lung.org/lung-health-diseases/lung-disease-lookup/lung-cancer/resource-library/lung-cancer-fact-sheet 2https://www.cancer.net/cancer-types/lung-cancer-non- small-cell/statistics, ³Wang F, Wang S and Zhou Q (2020) The Resistance Mechanisms of Lung Cancer Immunotherapy. Front. Oncol. 10:568059. doi: 10.3389/fonc.2020.568059, 4https://thoracickey.com/carcinomas-of-the-lung-classification-and-genetics/#F1-72 5Transl Lung Cancer Res 2021;10(7):3093-3105. Ann Oncol. 2017;28(11):2698-706. DOI: 10.1200/JCO.22.00912 Journal of Clinical Oncology Published online June 03, 2022. Clarivate, Disease Landscape and Forecast: NSCLC (2022). 1L, first line; 2L+, second line or greater; NSCLC, non-small cell lung cancer; ORR, objective response rate (best objective response as confirmed complete response or partial response), SOC, standard of care (docetaxel, docetaxel + ramucirumab, gemcitabine, pemetrexed) BioAtla| Overview 16#17Encouraging Phase 1 results with Mecbotamab Vedotin (BA3011) in refractory NSCLC patients Maximum Change From Baseline (%) 100 80 60 40 20 0 -20 -40 -60 -80 -100 bicatla AXL - TmPS=0 1.5mg/kg d1,8 Response at Variable Dosing AXL-TmPS=0 1.2mg/kg d1,8 Not Evaluable 1.2mg/kg d1 Confirmed PR Stage IV adenocarcinoma (multiple chemo PKIs and pembrolizumab failure) AXL + TmPS-80 1.8mg/kg d1,8 A partial response was achieved in the AXL-high NSCLC patient refractory to multiple chemo PKIs and pembrolizumab failure BioAtla| Overview 17#18Phase 2 study design with BA3011 (Mecbotamab Vedotin) in refractory NSCLC patients Initial interim analysis AXL+ ≥1 TmPS Monotherapy and Combination with PD-1/L1 All patients refractory to PD-1/L1, EGFR and / or ALK inhibitors Targeting up to ~20 pts bicatla Next step If definitive, move into part 2 Ability to continue interim enrollment up to ~40 patients, if desired Phase 2 part 2 Monotherapy (BA3011) and / or Combination (BA3011+Opdivo) n=TBD pending discussions with FDA Endpoints Primary endpoints 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 18#19Phase 2 part 1 BA3011 NSCLC initial interim analysis confirms Phase 1 signal supports advancing preparations for part 2 in refractory NSCLC 60 ORR (%) 50 40 30 20 10 0 bicatla 33% 3/9 NSQ+SQ 43% 3/7 All NSQ 50% 2*/4 NSQ BA3011 monotherapy 33% NSQ - non-squamous; SQ - squamous Responses include 2 confirmed partial responses (*) and one confirmed complete response (**) 1**/3 NSQ BA3011 + nivolumab SQ 0/2 15 patients enrolled as of July 2022: 4 patients currently on treatment did not yet have the opportunity to be followed for 3 months; 2 patients are not efficacy-evaluable; 9 efficacy evaluable patients - All patients failed prior PD-1 treatment(s) – median prior lines of therapy = 2.5 BioAtla| Overview 19#20Promising safety and tolerability profile emerging in NSCLC Phase 2 at the RP2D 1.8 mg/kg Q2W Characteristic Any Adverse Events (AES) Related AEs with CTCAE¹ Grade 3 or 4² Any related serious AEs² Related AEs leading to death² Related AEs leading to treatment discontinuation² bicatla Constipation Peripheral Neuropathy BA3011 (N=7) 6 (86%) 1 (14%) 1 (14%)* Diarrhea 0 0 BA3011 + Opdivo (N=4) 4 (100%) 2 (50%) 2 (50%)^ 0 0 ■ ■ ■ ■ No treatment-related deaths Few treatment-related SAES Grade 1-2 (9%) Grade 3-4 (0%) All Grade 1-2 (0%) Grade 1-2 (18%) Grade 3-4 (0%) Low-grade constipation observed is consistent with baseline levels seen in advanced cancer patients Interim data- Data cut-off of June 2, 2022 Note: ¹CTCAE: Common Terminology Criteria for Adverse Events. The NCI Common Terminology Criteria for Adverse Events is a descriptive terminology which is utilized for Adverse Event (AE) reporting. A grading (severity) scale is provided for each AE term. 2As assessed by the investigator. Missing responses are counted as related. * Hyperglycemia; ^creatinine increase & Acute kidney injury Company ma erial-confidential No AEs leading to treatment discontinuation No clinically meaningful on-target toxicity observed over background Differentiated profile due to avoiding on-target off-tumor toxicity BioAtla| Overview 20#21bicatla CAB-ROR2-ADC Platform BA3021 Ozuriftamab Vedotin - NSCLC, Melanoma, SSCHN#22Potential market opportunity in metastatic NSCLC ● >540K 2L+ people in the U.S. living with lung cancer¹ bicatla despite advances in 1L care, majority of patients progress³ ~200K ~75% newly diagnosed patients / year (U.S.) - majority advanced / metastatic² non-squamous cell represents majority of patients4 Available Treatment: 1L: Chemo + ICI 50% ORR5 2L+: SOC 10% - 20% ORR6,7 Target population: ~40K ROR2+ addressable 2L+ patients/year in the U.S.8, based on ROR2 positivity rate of ~30% Internal success threshold: 2L+ ORR of ~15% - 20% (approvability bar); 20%+ (commercially relevant) following BA3011 monotherapy ¹https://www.lung.org/lung-health-diseases/lung-disease-lookup/lung-cancer/resource-library/lung-cancer-fact-sheet 2https://www.cancer.net/cancer-types/lung-cancer-non- small-cell/statistics, ³Wang F, Wang S and Zhou Q (2020) The Resistance Mechanisms of Lung Cancer Immunotherapy. Front. Oncol. 10:568059. doi: 10.3389/fonc.2020.568059, 4https://thoracickey.com/carcinomas-of-the-lung-classification-and-genetics/#F1-72 5Transl Lung Cancer Res 2021;10(7):3093-3105. Ann Oncol. 2017;28(11):2698-706. DOI: 10.1200/JCO.22.00912 Journal of Clinical Oncology Published online June 03, 2022. Clarivate, Disease Landscape and Forecast: NSCLC (2022). 1L, first line; 2L+, second line or greater; NSCLC, non-small cell lung cancer; ORR, objective response rate (best objective response as confirmed complete response or partial response), SOC, standard of care (docetaxel, docetaxel + ramucirumab, gemcitabine, pemetrexed) BioAtla| Overview 22#23Encouraging Phase 1 results with BA3021 (Ozuriftamab Vedotin) in refractory patients with NSCLC Maximum % Change from Baseline in Sum of Target Lesions bicatla 30% 20% 10% 0% -10% -20% -30% -40% -50% -60% ROR2 + (**TmPS=100) 1.2mg/kg d1,8 I I I I I Suboptimal dose (1.2mg/kg 2Q3W) ROR2 - (**TmPS=0) 3mg/kg d1 Patient experienced tumor shrinkage prior to progression of metastatic bone lesions Response at Variable Dosing ROR2 + (**TmPS=45) 3.3mg/kg d1 NSCLC squamous tumor: 10mm to 0mm on first scan Not Evaluable 1.5mg/kg d1,8 Note: Not Evaluable (Strong, extensive fibroblastic stromal positivity reported) ROR2 + (**TmPS=95) 3.3mg/kg d1 ¶ I ROR2 + (**TmPS=70) 3mg/kg d1 * PR **Suboptimal dose 1.2 mg/kg 2Q3W. Tumor shrinkage occurred prior to progression of metastatic bone lesions. NSCLC squamous tumor 10mm to 0mm on first scan. TmPS = 16%, patient was refractory to four prior lines of therapy including cetuximab and pembrolizumab. ■ Two out of three ROR2+ patients had a confirmed partial response following ozuriftamab vedotin treatment BioAtla| Overview 23#24Potential market opportunity in metastatic melanoma ~1.3MM ● ● ~50% people in the U.S. living with melanoma¹ bicatla do not respond to PD-1 therapy in 1L setting² ~100K 30-40% newly diagnosed invasive cases / year (U.S.)¹ initial responders progress² 1L, first line; 2L+, second line or greater; ICIS - Immune checkpoint inhibitors. Available Treatment 1L: ICIs 33% - 50% ORR³; (BRAF / Mek inhibitors for BRAF+) Target population: ~5K ROR2+ addressable 2L+ patients/year in the U.S.1, based on a ROR2 positivity rate of ~10% Internal success threshold: 2L+ ORR of ~20% (approvability bar); 25%+ (commercially relevant) following BA3011 monotherapy 2L+: ICIS 9% -28% ORR (mono - combo, respectively)4 ¹Clarivate, Disease Landscape and Forecast: Malignant Melanoma (2022). www.cancer.net; www.cancer.org; 2Oncology (Williston Park). 33(4):141-8. ³Keytruda USPI accessed June 2022; Opdivo USPI accessed June 2022. 4VanderWalde A, Moon J, Bellasea S, et al. Ipilimumab plus nivolumab versus ipilimumab alone in patients with metastatic or unresectable melanoma that did not respond to anti-PD-1 therapy. Presented at: 2022 AACR Annual Meeting; April 8-13, 2022; New Orleans, LA. Abstract CT013. BioAtla| Overview 24#25Phase 1 & 2 Results in Stage IV Multi-Refractory Melanoma Complete Response Observed in 2 out of 2 ROR2+ Patients %change in Target Lesions 100 80 60 40 20 0 -20 -40 -60 -80 -100 0 bicatla 20 Data on file. ROR2 + Phase 2 Patient 40 60 80 Time (weeks) 100 120 140 ROR2 + Phase 1 Patient 160 Phase 1 Patient Details: ✓ Prior treatment failure: nivolumab followed by nivolumab + ipilimumab combination ✓Clearance of pulmonary metastases followed by normalization of adenopathy ✓ Continued CR off-treatment for over 2 yrs Oo Phase 2 Patient Details: ✓ Prior treatment failure: nivolumab followed by Dacarbazine ✓ Complete Response on 1st scan (3 doses) BioAtla| Overview 25#26Potential market opportunity in SCCHN ● ● >400K ~50% people living with head and bicatla neck cancer (U.S.)¹1 with locally advanced disease develop recurrent or refractory disease² ~66K 2L+ newly diagnosed cases / year (U.S.)¹ limited effective options post IL³ Available Treatment 1L: Pembro, cetuximab, platinum 36% ORR4 2L+: ICIS 13% -16% ORR4 Target population: ~12K ROR2+ addressable 2L+ patients/year in the U.S.1, based on a ROR2 positivity rate of ~60% Internal success threshold: 2L+ ORR of ~15% (approvability bar); 15%+ (commercially relevant) following BA3011 monotherapy ¹Clarivate, Disease Landscape and Forecast: SCCHN (2022). www.cancer.net; 2Argiris A, et al. (2017) Evidence-Based Treatment Options in Recurrent and/or Metastatic Squamous Cell Carcinoma of the Head and Neck. Front. Oncol. 7:72; ³Future Oncology, Jan. 2019. Vol. 15, No. 8; 4Ketruda USPI accessed June 2022; Opdivo USPI access June 2022. SCCHN, squamous cell carcinoma of the head and neck; 1L, first line; 2L, second line; 2L+, second line or greater; ICIS - Immune checkpoint inhibitors. BioAtla| Overview 26#27Phase 1 results with BA3021 support advancing into Phase 2 in multiple indications ROR2+ Tumor Types NSCLC Melanoma SCCHN bicatla Results ▪ PR in 2/3 patients who previously experienced failure on PD-1 and who received Ph2 dose or higher CR in 1 / 1 patient who previously experienced failure on PD-1 Clearance of pulmonary metastases followed by normalization of adenopathy ■ Continued CR off treatment for over 2 years . ▪ PR in 1/1 ROR2+ refractory to four prior lines of therapy including cetuximab and PD-1 (pembrolizumab) Promising safety and tolerability profile across multiple tumor types No ROR2 ADC or small molecules in the clinic to date, suggesting CAB-ROR2-ADC is a first-in-class therapy across multiple tumor types BioAtla| Overview 27#28Phase 2 study design with BA3021 (Ozuriftamab Vedotin) in refractory patients for each indication: NSCLC, Melanoma, and SCCHN Initial interim analysis ROR2+ ≥1 TmPS ● ● Melanoma*: PD1 failure NSCLC: PD1, EGFR or ALK failure SCCHN: PD1 alone or in combination w/ platinum failure Monotherapy and Combination with PD-1/L1 Targeting up to ~20 pts *To date, CR on first scan (3 doses), n=1 Next step If definitive, move into part 2 Ability to continue enrollment up to ~40 patients, if desired Phase 2 part 2 Monotherapy (BA3021) and / or Combination (BA3021+Opdivo) n=TBD pending discussions with FDA BA3011 dose 1.8 mg/kg Q2W. Inclusion criteria: measurable disease, ≥ 18 years, ECOG performance status 0 or 1. bicatla 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. Endpoints Primary endpoints ● ● Confirmed ORR per RECIST v1.1 AES or SAEs Secondary endpoints ● DOR, PFS, ORR, DCR, TTR, OS, tumor size BioAtla| Overview 28#29Naked Antibody Platform: CTLA-4 (BA3071) - Basket Trial bicatla#30BA3071 (CAB-CTLA-4) Best-in-class and potential for disruption of the I/O Market Research demonstrates challenges and opportunity in combining two Immune Checkpoint Inhibitors* I - Improves efficacy, but increases adverse events Greater % of patients discontinue therapy relative to monotherapy In NHP study, BA3071 achieved similar exposure levels to Ipi analog with significantly less toxicity in combination with nivo** bicatla Clinical Endpoint Progression Free Survival Grade 3 or 4 Adverse Events Discontinued Treatment Vehicle Control Nivo + Ipi Positive Control Nivo + CAB- BA3071 #1 #2 #3 #4 #5 #1 #2 #3 ###### Study date 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Cvno # #4 #1 or #2 #5 #1 #2 #3 #4 *Larkin et al., New Eng. J. Med.,373: 23-34, 2015 **Chang et al., PNAS 118 (9): 1-10, 2021 Nivo: 20mg/kg QW (12X human dose); Ipi or CAB-CTLA: 15mg/kg QW (45-60X human dose) Once weekly for four weeks exposure to Nivo + Ipi or CAB CTLA4 AUC168 = Area under the serum drug concentration-time curve from time zero to 168 hours; Cmax = Highest drug concentration observed in serum #5 Nivolumab (PD-1) ●●● 6.9 months 16.3% 7.7% Nivolumab (PD-1) + Ipilimumab (CTLA4) 11.5 months 55.0% 36.4% GI Symptoms A Liquid feces Non-formed feces Other Gl symptoms BioAtla| Overview 30#31Phase 1/2 trial design for CAB-CTLA-4 Naked Antibody (BA3071) A basket study FPI 3Q 2022 BA3071 7 mg Q3W (n=1-6) BA3071 21 mg Q3W (n=1-6) BA3071 monotherapy Objectives bicatla BA3071 70 mg Q3W (n=1-6) (DLT period) BA3071 210 mg Q3W (n=3-6) BA3071 in combination with nivolumab I BA3071 350 mg Q3W (n-3-6) ■ BA3071 700 mg Q3W (n-3-6) RP2D selection Phase 2 Expansion in 2H 2023 Possible Phase 2 Dose Expansion Cohorts RCC n=40 Melanoma n=40 NSCLC n=40 SCLC n=40 Bladder n=40 Gastric n=40 ■ Determine Phase 2 dose and MTD Characterize safety and clinical activity of BA3071 monotherapy and in combination with a PD-1 inhibitor (Nivolumab) Characterize PK, ADA and biomarkers aHCC n=40 Cervical n=40 BioAtla| Overview 31#32Bispecific Platform EpCAM x CD3 (BA3182) - Basket Trial bicatla#33Promising preclinical results with CAB-EpCAM x CAB-CD3 bispecific antibody in NHP and a colorectal cell line Tumor volume (mm³) 2500 2000 1500 1000 500 0 T 0 bicatla --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) MTD, maximum tolerate dose; NHP, non-human primate; WT = wild type; *from independent experiments. 50 ■ CAB-EpCAM x CAB-CD3 bispecific demonstrates efficient tumor shrinkage in a colorectal cancer cell line In non-GLP and GLP tox studies in NHP, dual selection results in high selectivity >160x higher therapeutic index MTD not reached (5mg/kg highest dose studied=NOAEL) No Cytokine release observed Long half-life in Cyno (~4 days) These promising results will enable IND submission and Phase 1 initiation for multiple solid tumors 2H2022 - ■ BioAtla| Overview 33#34A 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 IIT dosing Phase 2 IIT dosing Phase 2 initial interim data Phase 2 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 initial interim data Phase 2 interim update IND submission / Phase 1 initiation BioAtla| Overview 34#35BioAtla® is a clinical stage company focused on transforming cancer therapy with Conditionally Active Biologics (CABS) Proprietary technology Broad applicability in solid tumors Increases therapeutic bicatla window Two Phase 2 CAB-ADCs Interim BA3011 Phase 2 data supports advancing to registration studies in multiple sarcoma and NSCLC indications Diversified pipeline Near-term clinical readouts for multiple indications Strategic optionality Strong cash position $202.3MM (2022) with runway into 2H24 Sufficient through key clinical milestones BioAtla| Overview 35#36APPENDIX bicatla#37Board of Directors and Advisors bicatla Jay Short, PhD Chairman, Chief Executive Officer & Cofounder Board of Director Scott Smith President, Board of Director James Allison, PhD MD Anderson Cancer Center Scientific Advisor Mary Ann Gray, PhD Board of Director Lawrence Steinman, MD Board of Director Lawrence Fong, MD Cancer Immunotherapy Program, UCSF Scientific Advisor Padmanee Sharma, MD, PhD MD Anderson Cancer Center Scientific Advisor Sylvia McBrinn Board of Director Geoffrey Wahl, PhD Salk Institute Scientific Advisor Susan Moran, MD, MSCE Board of Director Eddie Williams Board of Director Michael Manyak, MD GlaxoSmithKline Scientific Advisor BioAtla| Overview 37