Comprehensive Review of ROS1 Tyrosine Kinase Inhibitors-Classified by Structural Designs and Mutation Spectrum (Solvent Front Mutation [G2032R] and Central β-Sheet 6 [Cβ6] Mutation [L2086F])

Despite ROS1 fusion-positive NSCLC accounting for approximately 1% to 2% of NSCLC, there is a long list of ROS1 tyrosine kinase inhibitors (TKIs) being developed in addition to three approved ROS1 TKIs, crizotinib, entrectinib and repotrectinib. Here, we categorized ROS1 TKIs by their structures (cyclic versus noncyclic) and inhibitory abilities (active against solvent front mutation G2032R or central β-sheet #6 [Cβ6] mutation L2086F) and summarized their reported clinical activity in order to provide a dashboard on how to use these ROS1 TKIs in various clinical situations. In addition, the less known Cβ6 mutation ROS1 L2086F confer resistances to next-generation ROS1 TKIs (repotrectinib, taletrectinib, and potentially NVL-520) that can be overcome by cabozantinib as documented in published patient reports and potentially by certain L-shaped type I ROS1 TKIs including ceritinib and gilteritinib, which is approved as a FLT3 inhibitor for relapsed refractory FLT3+ acute myeloid leukemia but have published preclinical activites against ROS1 (and ALK). Future clinical trials should investigate cabozantinib and gilteritinib to repurpose them as ROS1 TKIs that can target ROS1 L2086F Cβ6 mutation.

Efficacy of Taletrectinib (AB-106/DS-6051b) in ROS1+ NSCLC: An Updated Pooled Analysis of U.S. and Japan Phase 1 Studies

Introduction

Taletrectinib (AB-106/DS-6051b) is an oral, potent selective ROS1 and pan-NTRK tyrosine kinase inhibitor (TKI). Preclinically, taletrectinib has activity against ROS1 G2032R solvent-front mutation.

Methods

Patients with ROS1+ NSCLC enrolled into two phase 1 studies conducted in United States (U101, NCT02279433) and Japan (J102, NCT02675491) were analyzed for objective response rate (ORR) by the Response Evaluation Criteria in Solid Tumors version 1.1, progression-free survival, and safety.

Results

A total of 22 patients with ROS1+ NSCLC out of the total 61 patients enrolled were analyzed. Taletrectinib was given at the oral dose of 400 mg, 600 mg, 800 mg, and 1200 mg once daily and 400 mg twice daily as part of the dose-escalation schema. Data cutoff was August 19, 2020. Median follow-up time for all 22 patients was 14.9 months (95% confidence interval [CI]: 4.1–33.8). A total of 18 patients with ROS1+ were assessable for response. The confirmed ORR for ROS1 TKI-naive patients (N = 9) was 66.7% (95% CI: 35.4–87.9) with a disease control rate of 100% (70.1–100). The confirmed ORR for crizotinib pretreated patients (N = 6) was 33.3% (95% CI: 9.7–70.0) with a disease control rate of 88.3% (95% CI: 443.6–97.0). The median progression-free survival for ROS1 TKI-naive patients (N = 11) was 29.1 months (95% CI: 2.6–not reached) and 14.2 months (95% CI: 1.5–not reached) for crizotinib-refractory only patients (N = 8). The most common treatment-related adverse events were alanine transaminase elevations (72.7%), aspartate transaminase elevations (72.7%), nausea (50.0%), and diarrhea (50.0%). Grade 3 or higher adverse events were alanine transaminase elevations (18.2%), aspartate transaminase (9.1%), and diarrhea (4.5%).

Conclusions

Taletrectinib (AB106/DS6051b) has a meaningful clinical activity in patients with advanced ROS1+ NSCLC who are ROS1 TKI-naive or crizotinib-refractory and a manageable safety profile.

Thromboembolism in ALK+ and ROS1+ NSCLC patients: A systematic review and meta-analysis

INTRODUCTION

Increased thromboembolism (TE) has been reported in ALK+ and ROS1+ non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Odds ratios (OR) and hazard ratios (HR) of TE were calculated from meta-analysis and time-to-event analysis respectively for either ALK+ or ROS1+ NSCLC patients.

RESULTS

We identified eight studies (766 ALK+, 143 ROS1+, 2314 non-ALK+ and non-ROS1+ NSCLC patients) for the meta-analysis. For ALK+ NSCLC, the pooled OR was 2.00 (95% CI: 1.60-2.50) for total TE (TTE) by random-effects model, 2.10 (95% CI: 1.70-2.60) for venous thromboembolism (VTE), and 1.24 (95% CI: 0.80-1.91) for arterial thromboembolism (ATE). For ROS1+ NSCLC, the pooled OR was 3.08 (95% CI: 1.95-4.86) for TTE, and 3.15 (95% CI: 1.83-5.43) for VTE. Six studies (739 ALK+, 137 ROS1+, 561 EGFR+, 714 "wildtype" NSCLC patients) were included in the time-to-event analysis. The TTE incidence rate was 17.4 (95% CI: 15.3-19.5) per 100 pateint-years for ALK+ NSCLC, and 32.1 (95% CI: 24.6-39.6) per 100 patient-years for ROS1+ NSCLC with a 50 % cumulative incidence rate at year 3 of diagnosis. HR for TTE was 2.35 (95% CI: 1.90-2.92, p < 0.001) and 3.23 (95% CI: 2.40-4.34, p < 0.001) for ALK+ and ROS1+ NSCLC, respectively. Comparing ROS1+ NSCLC to ALK+ NSCLC, HR for TTE was 1.37 (95% CI: 1.05-1.79, p = 0.020).

CONCLUSIONS

ALK+ and ROS1+ NSCLC patients had an increased risk of TE. ROS1+ NSCLC had further increased risk of TE over ALK+ NSCLC.

Targeted therapies for ROS1-rearranged non-small cell lung cancer

ROS1 gene fusions account for approximately 1-2% of all cases of non-small cell lung cancer (NSCLC). Similarly to anaplastic lymphoma kinase (ALK)-positive NSCLC, patients with ROS1+ NSCLC tend to have minimal smoking and be of the female sex. In most cases, adenocarcinoma is the dominant histology. The ROS1 gene has homology to ALK and this structural similarity formed the basis for utilizing ALK inhibitors for ROS1+ NSCLC. On the basis of impressive progression-free survival of 19.2 months from the PROFILE 1001 trial, crizotinib obtained Food and Drug Administration (FDA) approval as first-line therapy for treatment of ROS1+ NSCLC. Since then, there has been a growing appreciation of the incidence of brain metastases in ROS1+ NSCLC and rates of central nervous system progression on crizotinib. Additionally, appreciation of novel resistance mechanisms to crizotinib has led to the development of newer tyrosine kinase inhibitors (TKIs). In this review, we highlight known and emerging TKIs for the management of ROS1+ NSCLC.