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

Current treatment and novel insights regarding ROS1-targeted therapy in malignant tumors

BACKGROUND

The proto-oncogene ROS1 encodes an intrinsic type I membrane protein of the tyrosine kinase/insulin receptor family. ROS1 facilitates the progression of various malignancies via self-mutations or rearrangements. Studies on ROS1-directed tyrosine kinase inhibitors have been conducted, and some have been approved by the FDA for clinical use. However, the adverse effects and mechanisms of resistance associated with ROS1 inhibitors remain unknown. In addition, next-generation ROS1 inhibitors, which have the advantage of treating central nervous system metastases and alleviating endogenous drug resistance, are still in the clinical trial stage.

METHOD

In this study, we searched relevant articles reporting the mechanism and clinical application of ROS1 in recent years; systematically reviewed the biological mechanisms, diagnostic methods, and research progress on ROS1 inhibitors; and provided perspectives for the future of ROS1-targeted therapy.

RESULTS

ROS1 is most expressed in malignant tumours. Only a few ROS1 kinase inhibitors are currently approved for use in NSCLC, the efficacy of other TKIs for NSCLC and other malignancies has not been ascertained. There is no effective standard treatment for adverse events or resistance to ROS1-targeted therapy. Next-generation TKIs appear capable of overcoming resistance and delaying central nervous system metastasis, but with a greater incidence of adverse effects.

CONCLUSIONS

Further research on next-generation TKIs regarding the localization of ROS1 and its fusion partners, binding sites for targeted drugs, and coadministration with other drugs is required. The correlation between TKIs and chemotherapy or immunotherapy in clinical practice requires further study.

Larotrectinib efficacy and safety in adult patients with tropomyosin receptor kinase fusion sarcomas

BACKGROUND

Larotrectinib, a first-in-class, highly selective tropomyosin receptor kinase (TRK) inhibitor, has demonstrated efficacy in adult and pediatric patients with various solid tumors harboring NTRK gene fusions. This subset analysis focuses on the efficacy and safety of larotrectinib in an expanded cohort of adult patients with TRK fusion sarcomas.

METHODS

Patients (≥18 years old) with sarcomas harboring NTRK gene fusions were identified from three clinical trials. Patients received larotrectinib 100 mg orally twice daily. Response was investigator-assessed per RECIST v1.1. Data cutoff was July 20, 2021.

RESULTS

At the data cutoff, 36 adult patients with TRK fusion sarcomas had initiated larotrectinib therapy: two (6%) patients had bone sarcomas, four (11%) had gastrointestinal stromal tumors, and 30 (83%) had soft tissue sarcomas. All patients were evaluable for response and demonstrated an objective response rate of 58% (95% confidence interval, 41-74). Patients responded well to larotrectinib regardless of number of prior lines of therapy. Adverse events (AEs) were mostly grade 1/2. Grade 3 treatment-emergent AEs (TEAEs) occurred in 15 (42%) patients. There were no grade 4 TEAEs. Two grade 5 TEAEs were reported, neither of which were considered related to larotrectinib. Four (11%) patients permanently discontinued treatment due to TEAEs.

CONCLUSIONS

Larotrectinib demonstrated robust and durable responses, extended survival benefit, and a favorable safety profile in adult patients with TRK fusion sarcomas with longer follow-up. These results continue to demonstrate that testing for NTRK gene fusions should be incorporated into the clinical management of adult patients with various types of sarcomas.

PLAIN LANGUAGE SUMMARY

Tropomyosin receptor kinase (TRK) fusion proteins result from translocations involving the NTRK gene and cause cancer in a range of tumor types. Larotrectinib is an agent that specifically targets TRK fusion proteins and is approved for the treatment of patients with TRK fusion cancer. This study looked at how well larotrectinib worked in adult patients with sarcomas caused by TRK fusion proteins. Over half of patients had a durable response to larotrectinib, with no unexpected side effects. These results show that larotrectinib is safe and effective in adult patients with TRK fusion sarcomas.

Pan-tumor survey of ROS1 fusions detected by next-generation RNA and whole transcriptome sequencing

BACKGROUND

Two ROS1 tyrosine kinase inhibitors have been approved for ROS1 fusion positive (ROS1+) non-small cell lung cancer (NSCLC) tumors. We performed a pan-tumor analysis of the incidence of ROS1 fusions to assess if more ROS1+ patients who could benefit from ROS1 TKIs could be identified.

METHODS

A retrospective analysis of ROS1 positive solid malignancies identified by targeted RNA sequencing and whole transcriptome sequencing of clinical tumor samples performed at Caris Life Science (Phoenix, AZ).

RESULTS

A total of 259 ROS1+ solid malignancies were identified from approximately 175,350 tumors that underwent next-generation sequencing (12% from targeted RNA sequencing [Archer]; 88% from whole transcriptome sequencing). ROS1+ NSCLC constituted 78.8% of the ROS1+ solid malignancies, follow by glioblastoma (GBM) (6.9%), and breast cancer (2.7%). The frequency of ROS1 fusion was approximately 0.47% among NSCLC, 0.29% for GBM, 0.04% of breast cancer. The mean tumor mutation burden for all ROS1+ tumors was 4.8 mutations/megabase. The distribution of PD-L1 (22C3) expression among all ROS1+ malignancies were 0% (18.6%), 1%-49% (29.4%), and ≥ 50% (60.3%) [for NSCLC: 0% (17.8%); 1-49% (27.7%); ≥ 50% (53.9%). The most common genetic co-alterations of ROS1+ NSCLC were TP53 (29.1%), SETD2 (7.3%), ARIAD1A (6.3%), and U2AF1 (5.6%).

CONCLUSIONS

ROS1+ NSCLC tumors constituted the majority of ROS1+ solid malignancies with four major fusion partners. Given that > 20% of ROS1+ solid tumors may benefit from ROS1 TKIs treatment, comprehensive genomic profiling should be performed on all solid tumors.

Understanding the feasibility of chemotherapeutic and immunotherapeutic targets against non-small cell lung cancers: an update of resistant responses and recent combinatorial therapies

Despite consistent progress in prompt diagnosis and curative therapies in the last decade, lung cancer (LC) continues to threaten mankind, accounting for nearly twice the casualties compared to prostate, breast, and other cancers. Statistics associate ~25% of 2021 cancer-related deaths with LC, more than 80% of which are explicitly caused by tobacco smoking. Prevailing as small and non-small cell pathologies, with respective occurring frequency of nearly 15% and 80-85%, non-small cell LCs (NSCLCs) are prominently distinguished into lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), subtypes. Since the first use of epidermal growth factor receptor (EGFR) inhibitor gefitinib for NSCLC treatment in 2002, immense progress has been made for targeted therapies with the next generation of drugs spanning across the chronological generations of small molecule inhibitors. The last two years have overseen the clinical approval of more than 10 therapeutic agents as first-line NSCLC medications. However, uncertain mutational aberrations as well as systemic resistant responses, and abysmal overall survival curtail the combating efficacies. Of late, immune checkpoint inhibitors (ICIs) against various molecules including programmed cell death-1 (PD-1) and its ligand (PD-L1) have been demonstrated as reliable LC treatment targets. Keeping these aspects in mind, this review article discusses the success of NSCLC chemo and immunotherapies with their characteristic effectiveness and future perspectives.

Emerging therapeutics and evolving assessment criteria for intracranial metastases in patients with oncogene-driven non-small-cell lung cancer

The improved survival outcomes of patients with non-small-cell lung cancer (NSCLC), largely owing to the improved control of systemic disease provided by immune-checkpoint inhibitors and novel targeted therapies, have highlighted the challenges posed by central nervous system (CNS) metastases as a devastating yet common complication, with up to 50% of patients developing such lesions during the course of the disease. Early-generation tyrosine-kinase inhibitors (TKIs) often provide robust systemic disease control in patients with oncogene-driven NSCLCs, although these agents are usually unable to accumulate to therapeutically relevant concentrations in the CNS owing to an inability to cross the blood-brain barrier. However, the past few years have seen a paradigm shift with the emergence of several novel or later-generation TKIs with improved CNS penetrance. Such agents have promising levels of activity against brain metastases, as demonstrated by data from preclinical and clinical studies. In this Review, we describe current preclinical and clinical evidence of the intracranial activity of TKIs targeting various oncogenic drivers in patients with NSCLC, with a focus on newer agents with enhanced CNS penetration, leptomeningeal disease and the need for intrathecal treatment options. We also discuss evolving assessment criteria and regulatory considerations for future clinical investigations.

Efficacy, safety and pharmacokinetics of Unecritinib (TQ-B3101) for patients with ROS1 positive advanced non-small cell lung cancer: a Phase I/II Trial

This phase I/II trial characterized the tolerability, safety, and antitumor activities of unecritinib, a novel derivative of crizotinib and a multi-tyrosine kinase inhibitor targeting ROS1, ALK, and c-MET, in advanced tumors and ROS1 inhibitor-naive advanced or metastatic non-small cell lung cancer (NSCLC) harboring ROS1 rearrangements. Eligible patients received unecritinib 100, 200, and 300 mg QD, and 200, 250, 300, and 350 mg BID in a 3 + 3 design during dose escalation and 300 and 350 mg BID during expansion. Phase II trial patients received unecritinib 300 mg BID in continuous 28-day cycles until disease progression or unacceptable toxicity. The primary endpoint was the objective response rate (ORR) per independent review committee (IRC). Key secondary endpoints included intracranial ORR and safety. The ORR of 36 efficacy evaluable patients in the phase I trial was 63.9% (95% CI 46.2%, 79.2%). In the phase II trial, 111 eligible patients in the main study cohort received unecritinib. The ORR per IRC was 80.2% (95% CI 71.5%, 87.1%) and the median progression-free survival (PFS) per IRC was 16.5 months (95% CI 10.2, 27.0). Additionally, 46.9% of the patients who received recommended phase II dose of 300 mg BID experienced grade 3 or higher treatment-related adverse events. Treatment-related ocular disorders and neurotoxicity occurred in 28.1% and 34.4% of patients, respectively, but none was grade 3 or higher. Unecritinib is efficacious and safe for ROS1 inhibitor-naive patients with ROS1-positive advanced NSCLC, particularly patients with brain metastases at baseline, strongly supporting that unecritinib should become one of the standards of care for ROS1-positive NSCLC.ClinicalTrials.gov identifier: NCT03019276 and NCT03972189.

Importance of ROS1 gene fusions in non-small cell lung cancer

Targeted therapy has become one of the standards of care for advanced lung cancer. More than 10 genetic aberrations have been discovered that are actionable and several tyrosine kinase inhibitors (TKIs) have been approved to target each of them. Among several genetic aberrations that are actionable in non-small cell lung cancer (NSCLC), ROS1 translocations also known as gene fusion proteins, are found in only 1%-2% of the patient population. ROS1 mutations can usually be detected using a combination of techniques such as immunohistochemistry (IHC), Fluorescence in-situ testing (FISH), polymerase chain reaction (PCR), and next-generation sequencing (NGS). However, RNA NGS and ctDNA NGS (liquid biopsies) also contribute to the diagnosis. There are currently numerous FDA-approved agents for these tumors, including crizotinib and entrectinib; however, there is in-vitro sensitivity data and clinical data documenting responses to ceritinib and lorlatinib. Clinical responses and survival rates with these agents are frequently among the best compared to other TKIs with genetic aberrations; however, intrinsic or extrinsic mechanisms of resistance may develop, necessitating research for alternative treatment modalities. To combat the mechanisms of resistance, novel agents such as repotrectenib, cabozantinib, talotrectinib, and others are being developed. In this article, we examine the literature pertaining to patients with ROS1 tumors, including epidemiology, clinical outcomes, resistance mechanisms, and treatment options.

Exceptional response to lorlatinib and cabozantinib in ROS1-rearranged NSCLC with acquired F2004V and L2086F resistance

Patients with ROS1-rearranged NSCLC demonstrate excellent disease control with ROS1-targeted therapy, but acquired resistance is inevitable. Of particular interest is the ROS1 L2086F kinase domain mutation which is refractory to all currently available ROS1 TKIs apart from cabozantinib. We present a case of a patient with metastatic ROS1-rearranged NSCLC with dual ROS1 F2004V and L2086F resistance mutations who radiographically responded to the combination of lorlatinib and cabozantinib in a patient with metastatic NSCLC. Furthermore, the patient experienced exceptional clinical improvement and tolerance with the combined use of lorlatinib and cabozantinib. This case builds the case for cabozantinib as an agent to overcome ROS1 L2086F resistance. It also highlights the efficacy and safety of using combination of ROS1 TKIs to overcome complex resistance patterns.

NVL-520 Is a Selective, TRK-Sparing, and Brain-Penetrant Inhibitor of ROS1 Fusions and Secondary Resistance Mutations

SIGNIFICANCE

The combined preclinical features of NVL-520 that include potent targeting of ROS1 and diverse ROS1 resistance mutations, high selectivity for ROS1 G2032R over TRK, and brain penetration mark the development of a distinct ROS1 TKI with the potential to surpass the limitations of earlier-generation TKIs for ROS1 fusion-positive patients. This article is highlighted in the In This Issue feature, p. 517.

Molecular pathways, resistance mechanisms and targeted interventions in non-small-cell lung cancer

Lung cancer is the leading cause of cancer-related mortality worldwide. The discovery of tyrosine kinase inhibitors effectively targeting EGFR mutations in lung cancer patients in 2004 represented the beginning of the precision medicine era for this refractory disease. This great progress benefits from the identification of driver gene mutations, and after that, conventional and new technologies such as NGS further illustrated part of the complex molecular pathways of NSCLC. More targetable driver gene mutation identification in NSCLC patients greatly promoted the development of targeted therapy and provided great help for patient outcomes including significantly improved survival time and quality of life. Herein, we review the literature and ongoing clinical trials of NSCLC targeted therapy to address the molecular pathways and targeted intervention progress in NSCLC. In addition, the mutations in EGFR gene, ALK rearrangements, and KRAS mutations in the main sections, and the less common molecular alterations in MET, HER2, BRAF, ROS1, RET, and NTRK are discussed. The main resistance mechanisms of each targeted oncogene are highlighted to demonstrate the current dilemma of targeted therapy in NSCLC. Moreover, we discuss potential therapies to overcome the challenges of drug resistance. In this review, we manage to display the current landscape of targetable therapeutic patterns in NSCLC in this era of precision medicine.

NSCLC as the Paradigm of Precision Medicine at Its Finest: The Rise of New Druggable Molecular Targets for Advanced Disease

Standard treatment for advanced non-small cell lung cancer (NSCLC) historically consisted of systemic cytotoxic chemotherapy until the early 2000s, when precision medicine led to a revolutionary change in the therapeutic scenario. The identification of oncogenic driver mutations in EGFR, ALK and ROS1 rearrangements identified a subset of patients who largely benefit from targeted agents. However, since the proportion of patients with druggable alterations represents a minority, the discovery of new potential driver mutations is still an urgent clinical need. We provide a comprehensive review of the emerging molecular targets in NSCLC and their applications in the advanced setting.

An updated patent review of small-molecule ROS1 kinase inhibitors (2015-2021)

INTRODUCTION

: C-ros oncogene 1 (ROS1) is the sole member of the ROS1 receptor tyrosine kinase (ROS1-RTK) family, which is involved in the formation of non-small cell lung cancer (NSCLC), gastric adenocarcinoma, colorectal cancer and other malignant tumors. At present, only crizotinib was approved for the treatment of advanced ROS1-positive NSCLC, and there have been reports of ROS1 mutations resulting in drug resistance. Consequently, it is necessary to develop new generations of inhibitors to overcome the existing problems.

AREAS COVERED

This review summarizes the inhibitors with ROS1 inhibitory activity which are undergoing clinical trials and recent advances in patented ROS1 small molecular inhibitors from 2015 to 2021.

EXPERT OPINION

ROS1 rearrangements have been found in approximately 1%-2% of patients with NSCLC. Since the approval of crizotinib as multi-targeted ALK/MET/ROS1 kinase inhibitor for ALK-mutated NSCLC therapy, the researchers are focusing on ROS1-mutated tumors, especially NSCLC. However, drug-resistant mutations have already been found in clinical application. Therefore, it is still urgent to develop new generation of ROS1 inhibitors.

NTRK Fusion in Non-Small Cell Lung Cancer: Diagnosis, Therapy, and TRK Inhibitor Resistance

Neurotrophic tropomyosin receptor kinase (NTRK) gene fusion has been identified as an oncogenic driver of various solid tumors, and it is rare in non-smalll cell lung cancer (NSCLC) with a frequency of approximately less than 1%. Next-generation sequencing (NGS) is of priority for detecting NTRK fusions, especially RNA-based NGS. Currently, the tropomyosin receptor kinase (TRK) inhibitors have shown promising efficacy and well tolerance in patients with NTRK fusion-positive solid tumors, regardless of tumor histology. The first-generation TRK inhibitors (larotrectinib and entrectinib) are recommended as the first-line treatment for locally advanced or metastatic NSCLC patients with positive NTRK fusion. However, TRK inhibitor resistance can eventually occur due to on-target or off-target mechanisms. Further studies are under investigation to overcome resistance and improve survival. Interestingly, NTRK fusion might be the mechanism of resistance to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKI) in NSCLC patients with EGFR mutation. Regarding immunotherapy, the efficacy of immune checkpoint inhibitors in NSCLC patients harboring NTRK fusion has yet to be well described. In this review, we elucidate the function of NTRK genes, summarize the diagnostic techniques for NTRK fusions, and present clinical data for TRK inhibitors; we also discuss potential mechanisms of resistance to TRK inhibitors.

Deepening the Knowledge of ROS1 Rearrangements in Non-Small Cell Lung Cancer: Diagnosis, Treatment, Resistance and Concomitant Alterations

ROS proto-oncogene 1 (ROS1) rearrangements are reported in about 1-2% of non-squamous non-small-cell lung cancer (NSCLC). After efficacy of crizotinib was demonstrated, identification of ROS1 translocations in advanced disease became fundamental to give patients the chance of specific and effective treatment. Different methods are available for detection of rearrangements, and probably the real prevalence of ROS1 rearrangements is higher than that reported in literature, as our capacity to detect gene rearrangements is improving. In particular, with next generation sequencing (NGS) techniques, we are currently able to assess multiple genes simultaneously with increasing sensitivity. This is leading to overcome the "single oncogenic driver" paradigm, and in the very near future, the co-existence of multiple drivers will probably emerge more frequently and represent a therapeutic issue. Since recently, crizotinib has been the only available therapy, but today, many other tyrosine kinase inhibitors (TKI) are emerging and seem promising both in first and subsequent lines of treatment. Indeed, novel inhibitors are also able to overcome resistance mutations to crizotinib, hypothesizing a possible sequential strategy also in ROS1-rearranged disease. In this review, we will focus on ROS1 rearrangements, dealing with diagnostic aspects, new therapeutic options, resistance issues and the coexistence of ROS1 translocations with other molecular alterations.