Repotrectinib exhibits potent antitumor activity in treatment-naïve and solvent-front-mutant ROS1-rearranged non-small cell lung cancer

Purpose: Although first-line crizotinib treatment leads to clinical benefit in ROS1^þ lung cancer, high prevalence of crizotinib-resistant ROS1-G2032R (ROS1^G2032R) mutation and progression in the central nervous system (CNS) represents a therapeutic challenge. Here, we investigated the antitumor activity of repotrectinib, a novel next-generation ROS1/TRK/ALKtyrosine kinase inhibitor (TKI) in ROS1^þ patient-derived preclinical models. Experimental Design: Antitumor activity of repotrectinib was evaluated in ROS1^þ patient-derived preclinical models including treatment-naïve and ROS1^G2032R models and was further demonstrated in patients enrolled in an on-going phase I/II clinical trial (NCT03093116). Intracranial antitumor activity of repotrectinib was evaluated in a brain-metastasis mouse model. Results: Repotrectinib potently inhibited in vitro and in vivo tumor growth and ROS1 downstream signal in treatment-naïve YU1078 compared with clinically available crizotinib, ceritinib, and entrectinib. Despite comparable tumor regression between repotrectinib and lorlatinib in YU1078-derived xenograft model, repotrectinib markedly delayed the onset of tumor recurrence following drug withdrawal. Moreover, repotrectinib induced profound antitumor activity in the CNS with efficient blood-brain barrier penetrating properties. Notably, repotrectinib showed selective and potent in vitro and in vivo activity against ROS1^G2032R. These findings were supported by systemic and intracranial activity of repotrectinib observed in patients enrolled in the on-going clinical trial. Conclusions: Repotrectinib is a novel next-generation ROS1-TKI with improved potency and selectivity against treatment-naïve and ROS1^G2032R with efficient CNS penetration. Our findings suggest that repotrectinib can be effective both as first-line and after progression to prior ROS1-TKI.