BioAtla Provides Clinical Program Updates And Upcoming 2023 Milestones

Clinical Program Updates

• Phase 2 Trial of Mecbotamab Vedotin (BA3011, NCT03425279) in Patients with:
  • AXL-positive NSCLC
    • Part 1 of the trial ongoing in patients who have previously experienced failure of PD-1/L1, EGFR, or ALK inhibitor therapy (average failure 3 lines of therapy)
    • 29 patients enrolled to date (as of January 2023)
      • 20 efficacy-evaluable patients (18 in the non-squamous adenocarcinoma group and 2 in the squamous cell carcinoma group)
        • In the non-squamous group, 10 of 18 had monotherapy and 8 of 18 had combination therapy with nivolumab
      • All CR / PRs observed were in the non-squamous group
        • 4 PRs were in the monotherapy group (4 of 10, ORR 40%)
        • 4 PRs were in the monotherapy PD-1 failure group (4 of 9, ORR 44%)
        • 1 CR in combination therapy, (1 of 8, ORR 12.5%)
    • Following BA3011 in both monotherapy and in combination with nivolumab in advanced NSCLC patients, the safety profile continues to be differentiated, with no new safety signals observed
  • AXL-positive Soft Tissue and Primary Bone Sarcomas
    • Following FDA feedback to the proposed Phase 2 part 2 of the potentially registrational sarcoma study, protocol for UPS study design, including primary endpoint and size of study, finalized and the study is being initiated.
    • Part 1 of the Phase 2 study:
      • Study is progressing with continued efficacy in UPS with 50.0% PFS at 12 weeks (n=10 patients)
      • Study ongoing in patients with liposarcoma, synovial sarcoma, and osteosarcoma with continued, encouraging PFS at 12 weeks
        • Liposarcoma – 66.7% PFS (n=8)
        • Synovial sarcoma – 53.5% PFS (n=5)
        • Osteosarcoma – 66.7% PFS (n=7)
    • In refractory sarcomas, BA3011 in both monotherapy and in combination with nivolumab is generally well-tolerated with no new safety signals observed
• Phase 1/2 Dose-Escalation Trial of CAB-CTLA-4 (BA3071) Across Multiple Solid Tumor Types responsive to CTLA-4
  • Trial ongoing with two of three cohorts completed without any DLTs or SAEs reported

Expected Timing for Key 2023 Milestones

• 1H23
  • Phase 2 study of mecbotamab vedotin (BA3011, NCT03425279) in patients with AXL-positive NSCLC
    • Initiating preparations for discussions with the FDA regarding the potentially registrational part 2 of the study in AXL-positive NSCLC patients.
    • Submission of Phase 2 part 1 interim data for presentation at ASCO
  • First patient dosed in Phase 2 part 2 study in AXL-positive UPS patients
  • Interim data in the Phase 2 part 1 ROR-2 positive NSCLC study
  • CAB-EpCAM x CAB-CD3 TCE (BA3182) Phase 1 study initiation
• 2H23
  • Phase 2 part 2 of the BA3011 study in NSCLC patients anticipated initiation
  • Interim data in the Phase 2 part 1 ROR-2 positive melanoma study
  • Interim data in the Phase 2 part 1 ROR-2 positive SCCHN study
  • Phase 1 data and Phase 2 initiation in CAB-CTLA-4 (BA3071) study