ABSTRACT
Although immune checkpoint blockade (ICB) has shown remarkable clinical benefit in a subset of patients with melanoma and lung cancer, most patients experience no durable benefit. The receptor tyrosine kinase AXL is commonly implicated in therapy resistance and may serve as a marker for therapy-refractory tumors, for example in melanoma, as we previously demonstrated. Here, we show that enapotamab vedotin (EnaV), an antibody-drug conjugate targeting AXL, effectively targets tumors that display insensitivity to immunotherapy or tumor-specific T cells in several melanoma and lung cancer models. In addition to its direct tumor cell killing activity, EnaV treatment induced an inflammatory response and immunogenic cell death in tumor cells and promoted the induction of a memory-like phenotype in cytotoxic T cells. Combining EnaV with tumor-specific T cells proved superior to either treatment alone in models of melanoma and lung cancer and induced ICB benefit in models otherwise insensitive to anti-PD-1 treatment. Our findings indicate that targeting AXL-expressing, immunotherapy-resistant tumors with EnaV causes an immune-stimulating tumor microenvironment and enhances sensitivity to ICB, warranting further investigation of this treatment combination. SIGNIFICANCE: These findings show that targeting AXL-positive tumor fractions with an antibody-drug conjugate enhances antitumor immunity in several humanized tumor models of melanoma and lung cancer.
Subject(s)
Immune Checkpoint Inhibitors/therapeutic use , Immunoconjugates/therapeutic use , Lung Neoplasms/therapy , Melanoma/therapy , Proto-Oncogene Proteins/immunology , Receptor Protein-Tyrosine Kinases/immunology , Animals , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Cell Line, Tumor , Combined Modality Therapy , Drug Resistance, Neoplasm/immunology , Drug Synergism , HEK293 Cells , Humans , Immune Checkpoint Inhibitors/administration & dosage , Immunoconjugates/administration & dosage , Immunotherapy , Lung Neoplasms/pathology , Male , Melanoma/pathology , Mice , Mice, Nude , Mice, Transgenic , Molecular Targeted Therapy/methods , Proto-Oncogene Proteins/antagonists & inhibitors , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Xenograft Model Antitumor Assays , Axl Receptor Tyrosine KinaseABSTRACT
Targeted therapies and immunotherapy have shown promise in patients with non-small cell lung cancer (NSCLC). However, the majority of patients fail or become resistant to treatment, emphasizing the need for novel treatments. In this study, we confirm the prognostic value of levels of AXL, a member of the TAM receptor tyrosine kinase family, in NSCLC and demonstrate potent antitumor activity of the AXL-targeting antibody-drug conjugate enapotamab vedotin across different NSCLC subtypes in a mouse clinical trial of human NSCLC. Tumor regression or stasis was observed in 17/61 (28%) of the patient-derived xenograft (PDX) models and was associated with AXL mRNA expression levels. Significant single-agent activity of enapotamab vedotin was validated in vivo in 9 of 10 AXL-expressing NSCLC xenograft models. In a panel of EGFR-mutant NSCLC cell lines rendered resistant to EGFR inhibitors in vitro, we observed de novo or increased AXL protein expression concomitant with enapotamab vedotin-mediated cytotoxicity. Enapotamab vedotin also showed antitumor activity in vivo in 3 EGFR-mutant, EGFR inhibitor-resistant PDX models, including an osimertinib-resistant NSCLC PDX model. In summary, enapotamab vedotin has promising therapeutic potential in NSCLC. The safety and preliminary efficacy of enapotamab vedotin are currently being evaluated in the clinic across multiple solid tumor types, including NSCLC.
