STCube said it will present new preclinical and clinical data on its BTN1A1-targeted therapeutic strategy for non-small cell lung cancer (NSCLC) at the 2025 World Conference on Lung Cancer (WCLC), scheduled for Sept. 6–9 in Barcelona, Spain.

Two abstracts related to STCube’s anti-BTN1A1 antibody, nelmastobart, have been accepted for presentation. The studies include results from patient-derived organoid (PDO)-based preclinical research and retrospective analyses of phase 1 clinical trial data.

The first abstract, titled “Targeting BTN1A1 in PD-L1-Negative NSCLC: A Clinically Actionable Immune Checkpoint for Docetaxel-Based Combination Therapy,” reported that BTN1A1 expression increases following chemotherapy with docetaxel, thereby enhancing response to nelmastobart.

Using patient-derived organoid models, STCube researchers found that BTN1A1 and PD-L1 are differentially expressed in NSCLC, and that docetaxel treatment specifically upregulated BTN1A1.

This increase led to greater responsiveness to anti-BTN1A1 therapy compared with anti-PD-L1 therapy.

“Chemotherapy-induced upregulation of BTN1A1 shows that targeting BTN1A1 could be a promising strategy for PD-L1-negative NSCLC patients who fail to respond to or develop resistance against current immunotherapies,” STCube CSO Yoo Sung-han said. “These findings highlight the clinical potential of BTN1A1-based combination strategies in treating refractory NSCLC.”

The second abstract, “BTN1A1 and Nuclear YAP1 Co-Expression as Predictive Biomarkers for Nelmastobart Efficacy in Lung Cancer: Findings from a Phase 1 Trial,” demonstrated that co-expression of BTN1A1 and nuclear YAP1 correlates with improved outcomes.

In an analysis of tissue samples from four lung cancer patients enrolled in the phase 1 trial (three with small cell lung cancer and one with NSCLC), patients positive for BTN1A1 and with high nuclear YAP1 expression showed longer progression-free survival (PFS).

“BTN1A1-high tumors also displayed a greater proportion of YAP1-positive cells, and patients with both biomarkers tended to show prolonged disease control and PFS,” Yoo said “This supports STCube’s biomarker-driven clinical strategy and strengthens the therapeutic rationale for nelmastobart.”

By validating BTN1A1 as a prognostic biomarker in colorectal and lung cancers, the company is advancing nelmastobart as a potential global first-in-class therapy.”