Oncogenic fusions: Targeting NTRK

Non-Small Cell Lung Cancer (NSCLC) is responsible for the highest number of cancer-related deaths in the United States. Thankfully, advancements in the detection and targeting of gene mutations have greatly improved outcomes for many patients. One significant mutation driving oncogenesis in various cancers, including NSCLC, is the neurotrophic tyrosine receptor kinase (NTRK) fusion. Presently, larotrectinib and entrectinib are the only FDA-approved therapies for NTRK-mutated cancers. Despite the efficacy and tolerability exhibited by these therapies, several clinical hurdles persist for physicians, including resistance mutations and limited penetration of the central nervous system (CNS), which diminishes their effectiveness. The treatment landscape for NTRK cancers is still being explored, with numerous new tyrosine kinase inhibitors currently in development or undergoing phase 1 and 2 clinical trials. In this review, we delve into both established and novel therapies targeting NTRK-mutated NSCLC.

Economic burden of locoregional and metastatic relapses in resectable early-stage non-small cell lung cancer in Spain

BACKGROUND

There are scarce data of the costs of non-small cell lung cancer (NSCLC) recurrence in Spain. The objective of this study is to assess the economic burden of disease recurrence, for both locoregional and/or metastatic relapses, after appropriate early-stage NSCLC treatment in Spain.

MATERIALS AND METHODS

A two-round consensus panel of Spanish oncologists and hospital pharmacists was conducted to collect information on patient's flow, treatments, use of healthcare resources and sick leaves in patients with relapsed NSCLC. A decision-tree model was developed to calculate the economic burden of disease recurrence after appropriate early-stage NSCLC. Both direct and indirect costs were considered. Direct costs included drug acquisition and healthcare resources costs. Indirect costs were estimated using the human-capital approach. Unit costs were obtained from national databases (euros of 2022). A multi-way sensitivity analysis was performed to provide a range to the mean values.

RESULTS

Among a cohort of 100 patients with relapsed NSCLC, 45 patients would have locoregional relapse (36.3 would eventually progress to metastasis and 8.7 would be considered in remission) and 55 patients would have metastatic relapse. Over time, 91.3 patients would experience a metastatic relapse (55 as first relapse and 36.6 after previous locoregional relapse). The overall cost incurred by the 100-patients cohort is €10,095,846 (€9,336,782 direct costs, €795,064 indirect costs). The average cost of a locoregional relapse is €25,194 (€19,658 direct costs, €5536 indirect costs), while the average cost a patient with metastasis who receives up to 4 lines of treatment is €127,167 (€117,328 direct, €9839 indirect).

CONCLUSIONS

To our knowledge, this is the first study that specifically quantifies the cost of relapse in NSCLC in Spain. Our findings shown that the overall cost of a relapse after appropriate treatment of early-stage NSCLC patients is substantial, and it increases considerably in the metastatic relapse setting, mainly due to the high cost and long duration of first-line treatments.

Targeting molecular alterations in non-small-cell lung cancer: what's next?

In recent years, major advances have been achieved in our understanding of non-small-cell lung cancer (NSCLC) with oncogenic driver alterations and in the specific treatment of these with tyrosine kinase inhibitors. Currently, state-of-the-art management of patients with NSCLC (particularly adenocarcinoma or non-adenocarcinoma but with mild tobacco exposure) consists of the determination of EGFR, ALK, ROS1 and BRAF status, as they have US FDA and EMA approved targeted therapies. The increase in molecular knowledge of NSCLC and the development of drugs against other targets has settled new therapeutic indications. In this review we have incorporated the development around MET, KRAS and NTRK in the diagnosis of NSCLC given the therapeutic potential that they represent, as well as the drugs approved for these indications.

Complications following novel therapies for non-small cell lung cancer

The emergence of tyrosine kinase inhibitors and immune checkpoint inhibitors has paved a new era for the management of non-small cell lung cancer, which has for many years lacked major clinical breakthroughs. Historically, 5-year overall survival remained below 5% in individuals with metastatic disease. These novel treatments have led to significant prolongation of survival in the locally advanced and metastatic setting, exceeding 25% in selected populations. However, they present new challenges to clinicians due to their inherently different spectrum of toxicity unique to each specific drug's pharmacodynamic profile. Internists commonly come across these side effects in their daily clinical practice. Their optimal recognition and management are of utmost importance, because it is associated with significant improvements in patient survival outcomes and their quality of life. The aim of this review is to summarize the complications following these novel treatments for non-small cell lung cancer.

Targeted Therapies for Lung Cancer Patients With Oncogenic Driver Molecular Alterations

Lung cancer has traditionally been classified by histology. However, a greater understanding of disease biology and the identification of oncogenic driver alterations has dramatically altered the therapeutic landscape. Consequently, the new classification paradigm of non-small-cell lung cancer is further characterized by molecularly defined subsets actionable with targeted therapies and the treatment landscape is becoming increasingly complex. This review encompasses the current standards of care for targeted therapies in lung cancer with driver molecular alterations. Targeted therapies for EGFR exon 19 deletion and L858R mutations, and ALK and ROS1 rearrangements are well established. However, there is an expanding list of approved targeted therapies including for BRAF V600E, EGFR exon 20 insertion, and KRAS G12C mutations, MET exon 14 alterations, and NTRK and RET rearrangements. In addition, there are numerous other oncogenic drivers, such as HER2 exon 20 insertion mutations, for which there are emerging efficacy data for targeted therapies. The importance of diagnostic molecular testing, intracranial efficacy of novel therapies, the optimal sequencing of therapies, role for targeted therapies in early-stage disease, and future directions for precision oncology approaches to understand tumor evolution and therapeutic resistance are also discussed.

Amivantamab for the treatment of EGFR exon 20 insertion mutant non-small cell lung cancer

INTRODUCTION

Amivantamab is a monoclonal bispecific anti-EGFR-MET antibody that is the first targeted therapy to be approved for non-small cell lung cancer (NSCLC) patients harboring EGFR exon 20 insertion mutations following progression on chemotherapy, marking a watershed moment for a class of mutations which is generally associated with poor outcomes.

AREAS COVERED

In this article, we outline the drug profile of amivantamab compared with EGFR kinase inhibitors under evaluation in EGFR exon 20 insertion mutant NSCLC. We also review the efficacy and safety data reported from the CHRYSALIS phase I trial, which forms the basis of the recent approval of amivantamab.

EXPERT OPINION

Unlike small molecule EGFR kinase inhibitors, amivantamab has an extracellular mode of action and dual activity against EGFR and MET. It remains to be determined what role MET inhibition plays in toxicity and efficacy and whether dual target inhibition can delay the onset of drug resistance in these cancers. Due to its large molecular size, amivantamab is expected to have poor activity to treat brain metastases. Building on the clinical data so far, future trials that will evaluate combination treatments with brain-penetrant EGFR kinase inhibitors will be critical to move the drug toward a first-line treatment.

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.

Association Between Medicare's National Coverage Determination and Utilization of Next-Generation Sequencing

PURPOSE

In 2018, Medicare issued a national coverage determination (NCD) providing reimbursement for next-generation sequencing (NGS) tests for beneficiaries with advanced or metastatic cancer and no previous NGS testing. We examined the association between NCD implementation and NGS utilization trends in Medicare beneficiaries versus commercially insured patients.

METHODS

This was a retrospective study of patients with advanced non-small-cell lung cancer (aNSCLC), metastatic colorectal cancer (mCRC), metastatic breast cancer (mBC), or advanced melanoma with a de novo or recurrent advanced diagnosis from January 1, 2011, through December 30, 2019, using a nationwide US electronic health record-derived deidentified database. Patients were classified by insurance and by advanced diagnosis date. NGS testing was assessed by receipt of first NGS test result ≤ 60 days of advanced diagnosis. Interrupted time series analysis assessed NGS utilization pre- and post-NCD effective date by insurance type.

RESULTS

The utilization and repeat NGS testing analysis included 70,290 and 4,295 patients, respectively. Use of NGS rose from < 1% in 2011 to > 45% in Q4 2019 in aNSCLC while remaining < 20% in mBC and advanced melanoma. Among patients with aNSCLC, mCRC, or mBC, NGS testing increased post-NCD versus pre-NCD (P < .05). There was no significant difference in trends pre- and post-NCD between Medicare beneficiaries and commercially insured patients in any tumor. Repeat NGS testing was similar before the NCD (Medicare v commercial: 24.8% v 28.5%). Post-NCD, fewer Medicare beneficiaries had repeat NGS testing (27.7% v 36.0%; P < .01).

CONCLUSION

Trends in NGS utilization significantly changed post-NCD, although the magnitude of change was not significantly different by insurance type, indicating private insurers may also be incorporating NCD guidance. Implementation of the NCD may have limited use of repeat NGS testing in Medicare beneficiaries.

Canadian Consensus for Biomarker Testing and Treatment of TRK Fusion Cancer in Adults

The tyrosine receptor kinase (TRK) inhibitors larotrectinib and entrectinib were recently approved in Canada for the treatment of solid tumours harbouring neurotrophic tyrosine receptor kinase (NTRK) gene fusions. These NTRK gene fusions are oncogenic drivers found in most tumour types at a low frequency (<5%), and at a higher frequency (>80%) in a small number of rare tumours (e.g., secretory carcinoma of the salivary gland and of the breast). They are generally mutually exclusive of other common oncogenic drivers. Larotrectinib and entrectinib have demonstrated impressive overall response rates and tolerability in Phase I/II trials in patients with TRK fusion cancer with no other effective treatment options. Given the low frequency of TRK fusion cancer and the heterogeneous molecular testing landscape in Canada, identifying and optimally managing such patients represents a new challenge. We provide a Canadian consensus on when and how to test for NTRK gene fusions and when to consider treatment with a TRK inhibitor. We focus on five tumour types: thyroid carcinoma, colorectal carcinoma, non-small cell lung carcinoma, soft tissue sarcoma, and salivary gland carcinoma. Based on the probability of the tumour harbouring an NTRK gene fusion, we also suggest a tumour-agnostic consensus for NTRK gene fusion testing and treatment. We recommend considering a TRK inhibitor in all patients with TRK fusion cancer with no other effective treatment options.

Molecular testing and targeted therapy for non-small cell lung cancer: Current status and perspectives

Molecular testing has become a mandatory component of the non-small cell lung cancer (NSCLC) management. The detection of EGFR, BRAF and MET mutations as well as the analysis of ALK, ROS1, RET and NTRK translocations have already been incorporated in the NSCLC diagnostic standards, and the inhibitors of these kinases are in routine clinical use. There are emerging biomarkers, e.g., KRAS G12C substitutions and HER2 activating alterations, which are likely to enter NSCLC guidelines upon the approval of the corresponding drugs. In addition to genetic examination, NSCLCs are usually subjected to the analysis of PD-L1 protein expression in order to direct the use of immune checkpoint inhibitors. Comprehensive NSCLC testing for multiple predictive markers requires the analysis of distinct biological molecules (DNA, RNA, proteins) and, therefore, the involvement of different analytical platforms (PCR, DNA sequencing, immunohistochemistry, FISH). There are ongoing efforts aimed at the integration of multiple NSCLC molecular assays into a single diagnostic pipeline.

A RESPONSE TO "THE POTENTIAL LONG-TERM COMPARATIVE EFFECTIVENESS OF LAROTRECTINIB AND ENTRECTINIB FOR SECOND-LINE TREATMENT OF TRK FUSION-POSITIVE METASTATIC LUNG CANCER"

DISCLOSURES: The writing of this letter was sponsored by Roche/Genentech. All authors are employees of, and hold stocks in, F. Hoffmann-La Roche Ltd/Genentech Inc.

Evaluation of NTRK immunohistochemistry as a screening method for NTRK gene fusion detection in non-small cell lung cancer

PURPOSE

The small molecule inhibitors larotrectinib and entrectinib have recently been approved as cancer agnostic drugs in patients with tumours harbouring a rearrangement of the neurotrophic tropomyosin receptor kinase (NTRK). These oncogenic fusions are estimated to occur in 0.1-3 % of non-small cell lung cancers (NSCLC). Although molecular techniques are most reliable for fusion detection, immunohistochemical analysis is considered valuable for screening. Therefore, we evaluated the newly introduced diagnostic immunohistochemical assay (clone EPR17341) on a representative NSCLC cohort.

METHODS

Cancer tissue from 688 clinically and molecularly extensively annotated NSCLC patients were comprised on tissue microarrays and stained with the pan-TRK antibody clone EPR17341. Positive cases were further analysed with the TruSight Tumor 170 RNA assay (Illumina). Selected cases were also tested with a NanoString NTRK fusion assay. For 199 cases, NTRK RNA expression data were available from previous RNA sequencing analysis.

RESULTS

Altogether, staining patterns for 617 NSCLC cases were evaluable. Of these, four cases (0.6 %) demonstrated a strong diffuse cytoplasmic and membranous staining, and seven cases a moderate staining (1.1 %). NanoString or TST170-analysis could not confirm an NTRK fusion in any of the IHC positive cases, or any of the cases with high mRNA levels. In the four cases with strong staining intensity in the tissue microarray, whole section staining revealed marked heterogeneity of NTRK protein expression.

CONCLUSION

The presence of NTRK fusion genes in non-small cell lung cancer is exceedingly rare. The use of the immunohistochemical NTRK assay will result in a small number of false positive cases. This should be considered when the assay is applied as a screening tool in clinical diagnostics.

The Potential Long-Term Comparative Effectiveness of Larotrectinib and Entrectinib for Second-Line Treatment of TRK Fusion-Positive Metastatic Lung Cancer

BACKGROUND

Larotrectinib and entrectinib are FDA-approved therapies for patients with non-small cell lung cancer (NSCLC) with neurotrophic receptor tyrosine kinase gene fusion (TRK fusion-positive) whose cancer has metastasized and progressed. Early evidence indicates that these targeted therapies may offer dramatic survival benefits versus traditional cytotoxic regimens, but it remains uncertain how larotrectinib and entrectinib compare with each other.

OBJECTIVE

To simulate and compare expected life-years and quality-adjusted life-years (QALYs) for both TRK inhibitors.

METHODS

We developed a partitioned survival model to project the long-term comparative effectiveness of larotrectinib versus entrectinib in second-line treatment of metastatic NSCLC. Larotrectinib survival data were derived from a 13-month follow-up of 12 patients with TRK fusion-positive NSCLC in the NCT02122913 (phase 1) and NCT02576431 (NAVIGATE) trials. Entrectinib survival data were derived from a 13-month follow-up of 10 patients with TRK fusion-positive NSCLC in the ALKA-372-001, STARTRK-1, and STARTRK-2 trials. For larotrectinib and entrectinib progression-free survival and overall survival (OS), in-trial survival was extrapolated using parametric curve fits. Exponential fits were selected for all survival models based on minimal Bayesian information criteria and clinical plausibility. Lifetime survival curves were used to estimate expected mean/median survival. QALYs were estimated by applying preprogression and postprogression health state utilities derived from the literature.

RESULTS

In the base case, treatment with larotrectinib and entrectinib resulted in 5.4 and 1.2 median preprogression life-years and 7.0 and 1.8 median total life-years, respectively. Mean preprogression life-years (QALYs) were 7.5 (5.0) and 1.9 (1.2), and mean total life-years (QALYs) were 9.2 (5.8) and 4.4 (2.4), respectively.

CONCLUSIONS

Among TRK inhibitors for metastatic NSCLC, larotrectinib is estimated to provide improved life-year and QALY outcomes versus entrectinib based on parametric extrapolations of in-trial survival data. Our analysis is limited by lack of NSCLC-specific data on entrectinib OS, the small samples of patients with NSCLC in the trials, and a cross-trial comparison. Future studies should re-evaluate the comparative effectiveness of larotrectinib versus entrectinib as more patients are treated and as long-term survival data mature.

DISCLOSURES

Funding for this study was contributed by Bayer Healthcare, which reviewed the manuscript drafts, and employees contributed to the manuscript as coauthors. Xia and Williamson are employees of Bayer Healthcare. Roth, Carlson, and Sullivan are consultants to Bayer Healthcare and retain rights to all final revisions to the manuscript. Carlson also reports fees from Adaptive Biotechnologies, unrelated to this work. Roth reports consulting fees from BMS, unrelated to this work.

Evaluating entrectinib as a treatment option for non-small cell lung cancer

INTRODUCTION

Entrectinib, an oral pan-TRK, ALK, and ROS1 inhibitor is approved as a first-line treatment for NTRK-rearranged solid tumors and ROS1-rearranged non-small cell lung cancer (NSCLC). It has demonstrated clinical efficacy for patients harboring the relevant gene rearrangement in both systemic and intracranial disease, regardless of the tumor type.

AREAS COVERED

In this review, the authors analyzed data from preclinical and clinical studies, the characteristics of entrectinib compared to those of other relevant inhibitors (currently available and/or under investigation), and the emerging resistance mechanisms. The authors then provide the readers with their future perspectives.

EXPERT OPINION

Entrectinib has been well studied across many tumor types, including NSCLC with ALK, ROS1, and NTRK rearrangements. The drug has demonstrated favorable properties with oral administration, prolonged response duration, high intracranial efficacy, and a favorable toxicity profile. However, with acquisition of resistance and the development of newer generation TKIs, the optimal place for entrectinib in the landscape of targeted therapies for NSCLC warrants further validation.