BioAtla presents data from ongoing dose escalation fo BA3182

BioAtla (BCAB) presented first-in-human data in a poster titled “Preliminary Results from a First-in-Human Phase 1 Study of a Dual-Conditionally Binding CAB-EpCAM x CAB-CD3 Bispecific T-cell Engager, BA3182, in Patients with Treatment Refractory Metastatic Adenocarcinoma” at the European Society for Medical Oncology Gastrointestinal Cancers Congress being held in Barcelona, Spain from July 2-5, 2025. In the ongoing Phase 1 dose-escalation clinical trial, as of June 20, 2025, 39 patients with heavily pretreated metastatic adenocarcinoma were dosed in cohorts ranging from 0.0026 mg to 0.6 mg BA3182 QW, with either 0, 1, or 2 priming dose delivered four to seven days prior to treatment dosing. The primary objectives of this trial are to characterize safety and tolerability with escalating doses for determining efficacious dose for guiding the selection of the recommended Phase 2 dose. Secondary objectives include evaluation of preliminary antitumor activity in different cancer types, pharmacokinetics, and any potential immunogenicity. Robust expression of EpCAM among adenocarcinomas of the colon, stomach, pancreas, biliary tract, lung, breast, prostate, and thyroid makes it a compelling bispecific T-cell engager target when reliably restricting antibody binding to the tumor microenvironment. Preclinical studies using dual CAB BA3182 demonstrated potent antitumor activity in a human colorectal carcinoma xenograft model with a greater than a 100-fold improvement in the therapeutic index compared to non-CAB EpCAM x CD3 variants. Data highlights from the poster include: Patients were heavily pretreated having received a median of 3 prior lines of therapy. Tumor types included a variety of adenocarcinomas including adenoid cystic carcinoma, breast, cholangiocarcinoma, colorectal, esophagus, gallbladder, lung, ovarian, and pancreas. Patients with colorectal carcinoma constituted 56% of enrolled patients. Intravenous formulation of BA3182 was administered to 17 patients at doses of 0.0026 mg to 0.032 mg weekly and the subcutaneous formulation was administered weekly to 22 patients at doses of 0.032 mg to 0.6 mg; reported results include data from a June 20, 2025 cutoff. Compared with IV dosing, plasma BA3182 levels associated with SC dosing showed an improved profile with similar trough concentrations. Adverse events were generally low-grade, transient, and readily manageable. Cytokine Release Syndrome that readily resolved was only observed with IV dosing prior to implementation of prophylactic tocilizumab for first treatment dose: G1 and G2. Early, transient, asymptomatic G1 to G3 hepatic transaminase elevations resolved without delaying next weekly treatment dose. Five patients achieved objective tumor size reductions: colorectal carcinoma, breast adenocarcinoma, cholangiocarcinoma, and non-small cell lung cancer. Prolonged progression-free intervals observed in 2 colorectal carcinoma pts: 11 months and 14 months. Dose escalation actively continues at 1.2 mg flat dosing; updated Phase 1 data are anticipated 2H2025.