Treatment of ALK-Rearranged Non-Small Cell Lung Cancer: Recent Progress and Future Directions

Therapeutic Targeting of the Anaplastic Lymphoma Kinase (ALK) in Neuroblastoma-A Comprehensive Update

Neuroblastoma (NBL) is an embryonic malignancy of the sympathetic nervous system and mostly affects children under the age of five. NBL is highly heterogeneous and ranges from spontaneously regressing to highly aggressive disease. One of the risk factors for poor prognosis are aberrations in the receptor tyrosine kinase anaplastic lymphoma kinase (ALK), which is involved in the normal development and function of the nervous system. ALK mutations lead to constitutive activation of ALK and its downstream signalling pathways, thus driving tumorigenesis. A wide range of steric ALK inhibitors has been synthesized, and several of these inhibitors are already in clinical use. Major challenges are acquired drug resistance to steric inhibitors and pathway evasion strategies of cancer cells upon targeted therapy. This review will give a comprehensive overview on ALK inhibitors in clinical use in high-risk NBL and on the potential and limitations of novel inhibitors. Because combinatory treatment regimens are probably less likely to induce drug resistance, a special focus will be on the combination of ALK inhibitors with drugs that either target downstream signalling pathways or that affect the survival and proliferation of cancer cells in general.

Complete remission for 4 years with crizotinib in advanced ALK-positive non-small cell lung cancer after thoracostomy for empyema

INTRODUCTION

Anaplastic lymphoma kinase (ALK) gene translocation occurs in 3%-5% of patients with non-small cell lung cancer (NSCLC), typically in younger patients. Crizotinib (tyrosine kinase inhibitor) has been considered as the standard of care for advanced ALK-positive lung cancer but it only gives a median progression-free survival of 7.7-11 months.

CASE

A 41-year-old old man, former smoker, was diagnosed with NSCLC in the right lung with manifest pleural effusion. This case was complicated by a pleural empyema and because of a trapped lung, there was an indication for the construction of a thoracostomy. After confirmation of the ALK translocation, therapy with crizotinib was started. After 8 weeks, there was excellent response, and 6 months later, all lesions were undetectable on CT scan. There was also complete healing of the thoracostomy wound.

CONCLUSION

This case describes a relatively young patient with a poor prognosis but with a remarkable and long-term response to crizotinib monotherapy.

Treatment of ALK-positive nonsmall cell lung cancer: recent advances

PURPOSE OF REVIEW

The review will highlight recent advances in development of ALK-TKIs and management of patients with ALK-positive nonsmall cell lung cancer.

RECENT FINDINGS

There has been rapid progress in the use of targeted therapies for ALK-positive NSCLC. Since the discovery, development and approval of crizotinib in 2011, three second-generation ALK-TKIs, ceritinib, alectinib and brigatinib have been approved by the FDA. A range of newer generation ALK inhibitors with improved potency against ALK and against mutations that confer resistance to crizotinib are in clinical development.

SUMMARY

Our review will discuss the recent phase III data with ceritinib and alectinib as well as clinical trials with other ALK inhibitors. We will also address two important issues in the management of ALK-positive NSCLC, prevention and treatment of brain metastases and management of emergent ALK-TKI resistance mechanisms.

Targeting ALK in Cancer: Therapeutic Potential of Proapoptotic Peptides

ALK is a receptor tyrosine kinase, associated with many tumor types as diverse as anaplastic large cell lymphomas, inflammatory myofibroblastic tumors, breast and renal cell carcinomas, non-small cell lung cancer, neuroblastomas, and more. This makes ALK an attractive target for cancer therapy. Since ALK–driven tumors are dependent for their proliferation on the constitutively activated ALK kinase, a number of tyrosine kinase inhibitors have been developed to block tumor growth. While some inhibitors are under investigation in clinical trials, others are now approved for treatment, notably in ALK-positive lung cancer. Their efficacy is remarkable, however limited in time, as the tumors escape and become resistant to the treatment through different mechanisms. Hence, there is a pressing need to target ALK-dependent tumors by other therapeutic strategies, and possibly use them in combination with kinase inhibitors. In this review we will focus on the therapeutic potential of proapoptotic ALK-derived peptides based on the dependence receptor properties of ALK. We will also try to make a non-exhaustive list of several alternative treatments targeting ALK-dependent and independent signaling pathways.

Entrectinib and other ALK/TRK inhibitors for the treatment of neuroblastoma

RTK plays important roles in many cellular signaling processes involved in cancer growth and development. ALK, TRKA, TRKB, TRKC, and ROS1 are RTKs involved in several canonical pathways related to oncogenesis. These proteins can be genetically altered in malignancies, leading to receptor activation and constitutive signaling through their respective downstream pathways. Neuroblastoma (NB) is the most common extracranial solid tumor in childhood, and despite intensive therapy, there is a high mortality rate in cases with a high-risk disease. Alterations of ALK and differential expression of TRK proteins are reported in a proportion of NB. Several inhibitors of ALK or TRKA/B/C have been evaluated both preclinically and clinically in the treatment of NB. These agents have had variable success and are not routinely used in the treatment of NB. Entrectinib (RXDX-101) is a pan-ALK, TRKA, TRKB, TRKC, and ROS1 inhibitor with activity against tumors with ALK, NTRK1, NTRK2, NTRK3, and ROS1 alterations in Phase I clinical trials in adults. Entrectinib’s activity against both ALK and TRK proteins suggests a possible role in NB treatment, and it is currently under investigation in both pediatric and adult oncology patients.

Phase I clinical and pharmacokinetic study of PM01183 (a tetrahydroisoquinoline, Lurbinectedin) in combination with gemcitabine in patients with advanced solid tumors

Background To determine the recommended dose (RD) of a combination of PM01183 and gemcitabine in patients with advanced solid tumors. Methods Forty-five patients received escalating doses of PM01183/gemcitabine on Days 1 and 8 every 3 weeks (d1,8 q3wk) following a standard 3 + 3 design. Results PM01183 3.5 mg flat dose (FD)/gemcitabine 1000 mg/m² was the highest dose level tested. Dose-limiting toxicities (DLTs) were mostly hematological and resulted in the expansion of a lower dose level (PM01183 3.5 mg FD/gemcitabine 800 mg/m²); 19 patients at this dose level were evaluable but >30% had DLT and >20% had febrile neutropenia. No DLT was observed in 11 patients treated at PM01183 3.0 mg FD/gemcitabine 800 mg/m², which was defined as the RD. This regimen was feasible and tolerable with manageable toxicity; mainly grade 3/4 myelosuppression. Non-hematological toxicity comprised fatigue, nausea, vomiting, and transaminases increases. Fifteen (33%) patients received ≥6 cycles with no cumulative hematological toxicity. Pharmacokinetic analysis showed no evidence of drug-drug interaction. Nine of 38 patients had response as per RECIST (complete [3%] and partial [21%]), for an overall response rate (ORR) of 24% (95% Confidence Interval [CI] 12-40%). Eleven patients (29%) had disease stabilization ≥4 months. Responses were durable (median of 8.5 months): overall median progression-free survival (PFS) was 4.2 months (95% CI, 2.7-6.5 months). Conclusions The RD for this combination is PM01183 3.0 mg FD (or 1.6 mg/m²)/gemcitabine 800 mg/m² d1,8 q3wk. This schedule is well tolerated and has antitumor activity in several advanced solid tumor types.

Discovery of Clinical Candidate CEP-37440, a Selective Inhibitor of Focal Adhesion Kinase (FAK) and Anaplastic Lymphoma Kinase (ALK)

Analogues structurally related to anaplastic lymphoma kinase (ALK) inhibitor 1 were optimized for metabolic stability. The results from this endeavor not only led to improved metabolic stability, pharmacokinetic parameters, and in vitro activity against clinically derived resistance mutations but also led to the incorporation of activity for focal adhesion kinase (FAK). FAK activation, via amplification and/or overexpression, is characteristic of multiple invasive solid tumors and metastasis. The discovery of the clinical stage, dual FAK/ALK inhibitor 27b, including details surrounding SAR, in vitro/in vivo pharmacology, and pharmacokinetics, is reported herein.

Aberrant expression of anaplastic lymphoma kinase in lung adenocarcinoma: Analysis of circulating free tumor RNA using one-step reverse transcription-polymerase chain reaction

Lung adenocarcinoma patients harboring anaplastic lymphoma kinase (ALK) gene rearrangements respond well to approved ALK inhibitors. However, to date, limited evidence is available regarding whether using circulating free tumor mRNA to identify aberrant ALK expression is possible, and its feasibility remains to be clearly addressed. The present study evaluated ALK expression by a one-step reverse transcription‑polymerase chain reaction (PCR) assay on the circulating free tumor mRNA from 12 lung adenocarcinoma patients. Additionally, the present study tested for ALK rearrangements by fluorescence in situ hybridization (FISH) and immunohistochemistry. A molecular genetic characterization was performed on tumor tissues and plasma samples. Aberrant ALK expression was detected in 2/12 patients using mRNA purified from plasma specimens and the results agreed with the FISH and immunohistochemistry findings of solid biopsy samples. The detection of aberrant ALK expression on circulating free tumor RNA may be feasible using a one‑step real‑time PCR assay and may be particularly helpful when a solid biopsy sample is not available.

'Inflammatory myofibroblastic tumour'-like dedifferentiation of anaplastic lymphoma kinase-rearranged lung adenocarcinoma

AIMS

Anaplastic lymphoma kinase (ALK) functions as an oncogenic driver in a subset of haematopoietic, epithelial and mesenchymal neoplasms. Activation of ALK most commonly occurs through gene fusion events, the presence of which predicts response to ALK-targeted inhibitors in some tumour types. Echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusions represent the majority of ALK rearrangements in lung adenocarcinomas and were, until recently, thought to be exclusive to that tumour type. However, recent work has identified EML4-ALK fusions in ~20% of inflammatory myofibroblastic tumours (IMTs), particularly in those arising in the lung. Here, we present a patient with an ALK-rearranged poorly differentiated lung adenocarcinoma with a predominant sarcomatoid component that was morphologically indistinguishable from IMT.

METHODS AND RESULTS

Targeted next-generation sequencing revealed EML4-ALK rearrangements in both components, with identical fusion sequences. Copy number analysis demonstrated focal gain of the MYC gene in the IMT-like component. The findings support a diagnosis of ALK-rearranged lung adenocarcinoma with IMT-like dedifferentiation.

CONCLUSIONS

Our findings suggest that ALK-driven epithelial and mesenchymal neoplasms exist on a morphological spectrum, and emphasize the need to consider translocation testing in pulmonary tumours with unusual sarcomatoid morphology.