Combined therapy with ALK inhibitors and a novel EGFR-targeting antibody‒drug conjugate as a strategy for ALK-rearranged non-small cell lung cancers.

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related death. Targeted monotherapies against the actionable oncogenic drivers, including anaplastic lymphoma kinase (ALK) rearrangement and epidermal growth factor receptor (EGFR) dysregulation, are well-established for molecularly selected NSCLC patients. However, therapeutic resistance remains a major clinical challenge, and combinatorial strategies targeting distinct signaling pathways may overcome the limitations of single-agent targeted therapies. LR004-VC-MMAE, a novel EGFR-targeting antibody‒drug conjugate (ADC), shows potent antitumor efficacy in multiple EGFR-positive xenografts, yet its therapeutic potential in ALK-rearranged NSCLC remains largely unexplored. Here, we evaluated a novel combinatorial strategy using ALK inhibitors (crizotinib, ceritinib, alectinib, and lorlatinib) in combination with LR004-VC-MMAE in ALK-rearranged NSCLC models. We found that both ALK and cell-surface EGFR were highly expressed in ALK-rearranged NCI-H3122 and NCI-H2228 cell lines but were expressed at low levels in the ALK-wild-type NCI-H460 cell line. All ALK inhibitor-ADC regimens synergistically suppressed proliferation in ALK-rearranged NSCLC cells, while exerting little synergy in ALK wild-type and EGFR-low counterparts. Moreover, crizotinib or ceritinib combined with LR004-VC-MMAE induced significantly greater apoptosis in NCI-H3122 cells compared with either single agent. Mechanistically, the crizotinib-LR004-VC-MMAE combination markedly downregulated ALK and EGFR expression and triggered apoptosis via mitochondrial depolarization-mediated caspase cascade activation and endoplasmic reticulum stress-induced unfolded protein response. In NCI-H3122 xenografts, this combination achieved synergistic tumor inhibition without increased toxicity compared with either treatment alone. Collectively, our findings demonstrate the synergistic antitumor activity of ALK inhibitor plus LR004-VC-MMAE against ALK-rearranged, EGFR-high NSCLC, providing a mechanistic rationale for further clinical development of this combination strategy.