Seok‐Young Kim

Abstract Purpose: Patient-derived organoids (PDO) of lung cancer has been recently introduced, reflecting the genomic landscape of lung cancer. However, clinical relevance of advanced lung adenocarcinoma organoids remains unknown. Here, we examined the ability of PDOs to predict clinical responses to targeted therapies in individual patients and to identify effective anticancer therapies for novel molecular targets. Experimental Design: Eighty-four organoids were established from patients with advanced lung adenocarcinoma. Formalin-fixed, paraffin-embedded tumor specimens from corresponding patients were analyzed by whole-exome sequencing (n = 12). Organoids were analyzed by whole-exome sequencing (n = 61) and RNA sequencing (n = 55). Responses to mono or combination targeted therapies were examined in organoids and organoid-derived xenografts. Results: PDOs largely retained somatic alterations including driver mutations of matching patient tumors. PDOs were able to recapitulate progression-free survival and objective responses of patients with non–small cell lung cancer receiving clinically approved tyrosine kinase inhibitors. PDOs recapitulated activity of therapeutic strategies under clinical investigation. YUO-071 harboring an EGFR exon 19 deletion and a BRAF G464A mutation and the matching patient responded to dabrafenib/trametinib combination therapy. YUO-004 and YUO-050 harboring an EGFR L747P mutation was sensitive to afatinib, consistent with the response in the matching patient of YUO-050. Furthermore, we utilized organoids to identify effective therapies for novel molecular targets by demonstrating the efficacy of poziotinib against ERBB2 exon 20 insertions and pralsetinib against RET fusions. Conclusions: We demonstrated translational relevance of PDOs in advanced lung adenocarcinoma. PDOs are an important diagnostic tool, which can assist clinical decision making and accelerate development of therapeutic strategies.

Abstract Purpose: Given that osimertinib is the only approved third-generation EGFR-TKI against EGFR activating and resistant T790M mutated non–small cell lung cancer (NSCLC), additional mutant-selective inhibitors with a higher efficacy, especially for brain metastases, with favorable toxicity profile are still needed. In this study, we investigated the antitumor efficacy of YH25448, an oral, mutant-selective, irreversible third-generation EGFR-TKI in preclinical models. Experimental Design: Antitumor activity of YH25448 was investigated in vitro using mutant EGFR-expressing Ba/F3 cells and various lung cancer cell lines. In vivo antitumor efficacy, ability to penetrate the blood–brain barrier (BBB), and skin toxicity of YH25448 were examined and compared with those of osimertinib using cell lines and PDX model. Results: Compared with osimertinib, YH25448 showed a higher selectivity and potency in kinase assay and mutant EGFR-expressing Ba/F3 cells. In various cell line models harboring EGFR activating and T790M mutation, YH25448 effectively inhibited EGFR downstream signaling pathways, leading to cellular apoptosis. When compared in vivo at equimolar concentrations, YH25448 produced significantly better tumor regression than osimertinib. Importantly, YH25448 induced profound tumor regression in brain metastasis model with excellent brain/plasma and tumor/brain area under the concentration–time curve value. YH25448 rarely suppressed the levels of p-EGFR in hair follicles, leading to less keratosis than osimertinib in animal model. The potent systemic and intracranial activity of YH25448 has been shown in an ongoing phase I/II clinical trial for advanced EGFR T790M mutated NSCLC (NCT03046992). Conclusions: Our findings suggest that YH25448 is a promising third-generation EGFR inhibitor, which may be more effective and better tolerated than the currently approved osimertinib.

Abstract Purpose: Although first-line crizotinib treatment leads to clinical benefit in ROS1+ lung cancer, high prevalence of crizotinib-resistant ROS1-G2032R (ROS1G2032R) 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/ALK-tyrosine kinase inhibitor (TKI) in ROS1+ patient-derived preclinical models. Experimental Design: Antitumor activity of repotrectinib was evaluated in ROS1+ patient-derived preclinical models including treatment-naïve and ROS1G2032R 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 ROS1G2032R. 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 ROS1G2032R with efficient CNS penetration. Our findings suggest that repotrectinib can be effective both as first-line and after progression to prior ROS1-TKI.