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.

Rare driver alterations in nonsmall cell lung cancer: novel targeted drugs

PURPOSE OF REVIEW

The current review presents clinically relevant driver alterations in nonsmall cell lung cancer (NSCLC) and the targeted treatments currently available for clinical use as well as those in clinical trials and advanced stages of drug development.

RECENT FINDINGS

Mesenchymal-epithelial transition factor, human epidermal growth factor receptor 2, proto-oncogene B-RAF (BRAF), proto-oncogene tyrosine-protein kinase ROS (ROS1), rearranged during transfection (RET) and neurotrophic tyrosine kinase are rare genetic driver alterations, each present in a small subset of patients with NSCLC. Treatments targeting BRAF, ROS1, RET and neurotrophic tyrosine kinase are approved in Europe, and promising treatments targeting mesenchymal-epithelial transition factor and human epidermal growth factor receptor 2 are available in clinical trials and compassionate use programs. The response rates, duration of response and tolerability observed in trials of targeted drugs in this setting are presented in detail here.

SUMMARY

While rare driver alterations are, by definition, rare, their recognition can change the course of NSCLC for those patients affected. Targeted treatments for many rare driver alterations are well tolerated and effective. Screening for molecular changes in advanced NSCLC should include screening for rare drivers, and patients should be directed to clinical trials in setting where treatment of the driver alterations is not otherwise available.

ROS1 Targeted Therapies: Current Status

PURPOSE OF REVIEW

Molecular drivers are increasingly identified as therapeutic targets for non-small cell lung cancer (NSCLC). This review focuses on the role of ROS1 inhibitors in treating relapsed/metastatic ROS-1 altered (ROS1+) NSCLC.

RECENT FINDINGS

Four FDA-approved drugs have significant activity against ROS1+ NSCLC: crizotinib, ciritinib, lorlatinib, and entrectinib. Each drug yields an overall response rates exceeding 60% with ciritinib, lorlatinib, and entrectinib possessing intracranial activity. The drugs have manageable toxicity profiles. ROS1 alterations are rare molecular drivers of NSCLC that can be effectively treated with a variety of ROS1-targetd drugs. New agents are being identified that may treat resistance mutations.

Treatment of Rare Mutations in Patients with Lung Cancer

Lung cancer is a worldwide prevalent malignancy. This disease has a low survival rate due to diagnosis at a late stage challenged by the involvement of metastatic sites. Non-small-cell lung cancer (NSCLC) is presented in 85% of cases. The last decade has experienced substantial advancements in scientific research, leading to a novel targeted therapeutic approach. The newly developed pharmaceutical agents are aimed towards specific mutations, detected in individual patients inflicted by lung cancer. These drugs have longer and improved response rates compared to traditional chemotherapy. Recent studies were able to identify rare mutations found in pulmonary tumors. Among the gene alterations detected were mesenchymal epithelial transition factor (MET), human epidermal growth factor 2 (HER2), B-type Raf kinase (BRAF), c-ROS proto-oncogene (ROS1), rearranged during transfection (RET) and neurotrophic tyrosine kinase (NTRK). Ongoing clinical trials are gaining insight onto possible first and second lines of medical treatment options intended to enable progression-free survival to lung cancer patients.

Breakthrough in targeted therapy for non-small cell lung cancer

Non-small cell lung cancer (NSCLC) remains by far the single most common malignancy of lung cancer which causes more and more mortality in recent years. NSCLC accounts for more than 80 % of lung cancers, and the vast majority of patients were found to be in advanced inoperable stages. Chemotherapy used to be the main treatment for NSCLC, but due to its obvious side effects. Chemotherapy gradually withdrew from the stage of history. In recent years, cellular and molecular biotechnology has developed rapidly, and researchers have begun to target key genes and regulatory molecules for treatment. Targeted drugs have also emerged. The purpose of this review is to introduce important research achievements in recent years and the treatment progress of new drugs.