BioAtla, LLC announced the treatment of the first patient in its clinical trial BA3021-001 for BioAtla's BA3021, a novel conditionally active ROR2-targeted antibody-drug conjugate (CAB-ROR2-ADC). This is a multi-center, open-label, Phase 1/2 study designed to evaluate the safety, tolerability, pharmacokinetics, immunogenicity and antitumor activity of BA3021 in patients with advanced solid tumors including non-small cell lung cancer (NSCLC), triple negative breast cancer and soft tissue sarcoma. CAB-ROR2-ADC is BioAtla's second CAB investigational product to enter clinical trials following BA3011, CAB-AXL-ADC in February of 2018. The ROR2 transmembrane protein tyrosine kinase is an onco-fetal protein that acts as a non-canonical Wnt 5A receptor. ROR2 is found to be highly expressed during embryonic development and in several important cancer types, and the level of expression in tumors is tightly correlated with patient prognosis. Recently, ROR2 and its ligand Wnt 5A have been shown to be induced in cancers that are resistant to treatment with immune checkpoint inhibitors such as anti-PD-1 antibody immune therapy suggesting a mechanistic role of this receptor-ligand axis in resistance to standard cancer treatments resulting in relapsing, minimal residual disease. However, low to moderate levels of expression of ROR2 in multiple normal adult tissues are predicted based on RNA expression, histological analysis and functional studies. To minimize the risk of potential disruption of normal function of ROR2 receptors on normal cells, BioAtla applies its proprietary CAB technology to develop its CAB antibody-drug conjugate (ADC) targeting ROR2 with the intent to activate binding to the ROR2 receptor only in the tumor microenvironment and deliver the toxic payload to the cancerous cells. The CAB-ROR2-ADC BA3021 is designed to maximize efficacy on ROR2 expressing tumors while minimizing toxicity, leading to better clinical outcomes.