Abstract 469: Quaratusugene ozeplasmid mediated TUSC2 upregulation in EML4-ALK bearing non-small cell lung carcinoma induces apoptosis and is highly effective in preclinical studies.

Abstract Background: Non-Small Cell Lung Carcinoma (NSCLC) harboring the EML4-ALK fusion gene (Echinoderm Microtubule-Associated Protein-Like 4-Anaplastic Lymphoma Kinase) comprises about 5% of NSCLC cases. Tumors with this genetic alteration are initially responsive to ALK Tyrosine Kinase Inhibitors (TKIs), which constitute first- and second-line therapy. However, nearly all ALK-positive (ALK+) lung cancers ultimately develop resistance to ALK TKIs, highlighting the urgent need for alternative treatment options. Methods and Results: Tumor Suppressor Candidate 2 (TUSC2) is a tumor suppressor gene with low endogenous expression in NSCLC. Quaratusugene ozeplasmid (QO), developed by Genprex, is a novel gene therapy that encapsulates the TUSC2 plasmid in non-viral lipid nanoparticles, effectively upregulating TUSC2 in cancer cells. We evaluated TUSC2 expression in a range of ALK+ cell lines and patient-derived organoids (PDOs), both prior to and following exposure to QO. Our findings show that QO-driven TUSC2 overexpression initiates a robust pro-apoptotic response in ALK+ models, not only in cells that are sensitive but also with acquired resistance (generated in the lab) to the ALK inhibitor, alectinib. This is evidenced by increased pro-apoptotic markers and lower cell viability when QO is used in combination with alectinib. To further assess the QO and alectinib combination, we tested it in two in vivo models: (1) an alectinib-sensitive model using subcutaneous injection of NCI-H2228 ALK+ cells into nude mice, and (2) an alectinib-resistant model using ALK167 PDX implants in NSG mice. Once tumors reached ∼ 100 mm3, mice were randomized into four groups: vehicle control; QO alone (25 µg/mouse, IV, every three days); alectinib alone (0.5 mg/kg for sensitive or 15 mg/kg for resistant, oral, daily); and QO plus alectinib at the same doses. In the sensitive model, tumors in the alectinib-treated group shrank by 60%. Notably, treatment with QO alone, and particularly QO combined with alectinib, resulted in 79% tumor shrinkage (p value 0.0135 versus control), demonstrating a 23% improved outcome than alectinib alone. This suggests that QO might serve as a valuable adjunct therapy, especially for patients who have advanced disease and/or experience resistance to TKIs. Major new unpublished results: In the resistant model, the QO and alectinib combination produced a synergistic effect, achieving the greatest tumor reduction and improved overall survival (p value 0.0001 versus control), further supporting the clinical potential of this therapeutic strategy in ALK+ NSCLC. Altogether, our in vitro and in vivo studies indicate that QO-mediated TUSC2 overexpression in ALK+ NSCLC effectively curtails tumor growth and proliferation via activation of apoptotic pathways, providing a compelling rationale for progressing towards clinical trial. Citation Format: Ananya Banerjee, Neeke Busette, Xu Cheng, Kerslee Kohagen, Liwei Bao, Lluis Lopez-Barcons, Mark S. Berger, Matthew B. Soellner, Angel Qin, Sofia Merajver, Nathan Merrill. Quaratusugene ozeplasmid mediated TUSC2 upregulation in EML4-ALK bearing non-small cell lung carcinoma induces apoptosis and is highly effective in preclinical studies abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 469.