Design of phase I combination trials: recommendations of the Clinical Trial Design Task Force of the NCI Investigational Drug Steering Committee

Anticancer drugs are combined in an effort to treat a heterogeneous tumor or to maximize the pharmacodynamic effect. The development of combination regimens, while desirable, poses unique challenges. These include the selection of agents for combination therapy that may lead to improved efficacy while maintaining acceptable toxicity, the design of clinical trials that provide informative results for individual agents and combinations, and logistic and regulatory challenges. The phase I trial is often the initial step in the clinical evaluation of a combination regimen. In view of the importance of combination regimens and the challenges associated with developing them, the Clinical Trial Design (CTD) Task Force of the National Cancer Institute Investigational Drug Steering Committee developed a set of recommendations for the phase I development of a combination regimen. The first two recommendations focus on the scientific rationale and development plans for the combination regimen; subsequent recommendations encompass clinical design aspects. The CTD Task Force recommends that selection of the proposed regimens be based on a biologic or pharmacologic rationale supported by clinical and/or robust and validated preclinical evidence, and accompanied by a plan for subsequent development of the combination. The design of the phase I clinical trial should take into consideration the potential pharmacokinetic and pharmacodynamic interactions as well as overlapping toxicity. Depending on the specific hypothesized interaction, the primary endpoint may be dose optimization, pharmacokinetics, and/or pharmacodynamics (i.e., biomarker).

Tackling Crizotinib Resistance: The Pathway from Drug Discovery to the Pediatric Clinic

Neuroblastoma is a childhood malignancy that has not yet benefitted from the rapid progress in the development of small-molecule therapeutics for cancer. An opportunity to take advantage of pharmaceutical innovation in this area arose when the identification of ALK fusion proteins in non-small cell lung cancer (NSCLC) occurred in parallel to the discovery of point mutations of ALK in neuroblastomas. ALK is now known to be a marker of poor outcome in neuroblastoma, and therefore, urgent development of specific ALK inhibitors to treat this devastating disease is a necessity. However, the translation of small molecules from adult directly into pediatric practice has thus far been challenging, due to mutation-specific structural variances in the ALK kinase domain. We discuss how the most recent structural and biological characterizations of ALK are directing preclinical and clinical studies of ALK inhibitors for both NSCLC and neuroblastoma.

Whole-genome sequencing of an aggressive BRAF wild-type papillary thyroid cancer identified EML4-ALK translocation as a therapeutic target

BACKGROUND

Recent advances in the treatment of cancer have focused on targeting genomic aberrations with selective therapeutic agents. In radioiodine resistant aggressive papillary thyroid cancers, there remain few effective therapeutic options. A 62-year-old man who underwent multiple operations for papillary thyroid cancer and whose metastases progressed despite standard treatments provided tumor tissue.

METHODS

We analyzed tumor and whole blood DNA by whole genome sequencing, achieving 80× or greater coverage over 94 % of the exome and 90 % of the genome. We determined somatic mutations and structural alterations.

RESULTS

We found a total of 57 somatic mutations in 55 genes of the cancer genome. There was notably a lack of mutations in NRAS and BRAF, and no RET/PTC rearrangement. There was a mutation in the TRAPP oncogene and a loss of heterozygosity of the p16, p18, and RB1 tumor suppressor genes. The oncogenic driver for this tumor is a translocation involving the genes for anaplastic lymphoma receptor tyrosine kinase (ALK) and echinoderm microtubule associated protein like 4 (EML4). The EML4-ALK translocation has been reported in approximately 5 % of lung cancers, as well as in pediatric neuroblastoma, and is a therapeutic target for crizotinib.

CONCLUSIONS

This is the first report of the whole genomic sequencing of a papillary thyroid cancer in which we identified an EML4-ALK translocation of a TRAPP oncogene mutation. These findings suggest that this tumor has a more distinct oncogenesis than BRAF mutant papillary thyroid cancer. Whole genome sequencing can elucidate an oncogenic context and expose potential therapeutic vulnerabilities in rare cancers.

Novel agents in development for advanced non-small cell lung cancer

The identification of EGFR mutations and ALK rearrangements in nonsmall cell lung cancer (NSCLC) has led to the rapid development of targeted therapies and significant changes in the treatment paradigm. Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) and crizotinib are now standard therapies for patients with the appropriate molecular alteration. Current investigations are determining the mechanisms of resistance to targeted therapies and developing novel agents to combat resistance. For patients with KRAS mutant NSCLC, a phase III trial of the MEK inhibitor, selumetinib, has been initiated. For patients without a defined mutation or a mutation without a known targeted therapy, immunotherapy, ganetespib, nintedanib and MET inhibitors in combination with EGFR TKIs are in development. Preliminary results of phase III trials raise doubts about the future development of dacomitinib as a second-line agent.

Non-Small Cell Lung Cancer beyond Biomarkers: The Evolving Landscape of Clinical Trial Design

The approval of EGFR and ALK directed tyrosine kinase inhibitors materialized the concept of tailoring therapy on the basis of specific biomarkers for treating patients with NSCLC. Research for other biologics, although demonstrating clinical benefit, has been less successful so far for producing biomarkers that predict response. Blocking angiogenesis is the prototype for the agents that belong in the latter group that target specific molecules, yet they are currently approved for relatively unselected groups of patients. In order to meet the goal of personalizing care in the various settings of NSCLC, a wealth of biologics and compounds are currently being tested in clinical trials in different phases of clinical development. In a subset of the relevant studies, a biomarker perspective is appreciated. This review summarizes the clinical rationale of the major ongoing phase II and III NSCLC studies that employ targeting specific molecules with novel agents, as well as innovative strategies, and includes a comparative discussion of the different designs.

Crizotinib: A comprehensive review

Anaplastic lymphoma kinase (ALK) gene rearrangements are present in a small subset of non-small-cell lung cancers. ALK-positivity confers sensitivity to small-molecule ALK kinase inhibitors, such as crizotinib. The integration of crizotinib into standard treatment practice in NSCLC will rest on the widespread implementation of an effective screening system for newly diagnosed patients with NSCLC which is flexible enough to incorporate new targets as treatments are developed for them. Phase I and II studies of crizotinib in ALK-positive lung cancer have demonstrated significant activity and impressive clinical benefit, which led to its early approval by USFDA in 2011. Although crizotinib induces remissions and extends the lives of patients, there have been reports of emerging resistance to Crizotinib therapy. In this review, we discuss the history, mechanism of action, uses, adverse effects, dose modifications and future challenges and opportunities for patients with ALK-positive lung cancers.

The clinical development of MEK inhibitors

Aberrant activation of the RAS-RAF-MEK-ERK1/2 pathway occurs in more than 30% of human cancers. As part of this pathway, MEK1 and MEK2 have crucial roles in tumorigenesis, cell proliferation and inhibition of apoptosis and, therefore, MEK1/2 inhibition is an attractive therapeutic strategy in a number of cancers. Highly selective and potent non-ATP-competitive allosteric MEK1/2 inhibitors have been developed and assessed in numerous clinical studies over the past decade. These agents are not efficacious in a broad range of unselected cancers, although single-agent antitumour activity has been detected mainly in tumours that harbour mutations in genes encoding the members of the RAS and RAF protein families, such as certain melanomas. Combinations of MEK1/2 inhibitors and cytotoxic chemotherapy, and/or other targeted agents are being studied to expand the efficacy of this class of agents. Identifying predictive biomarkers, and delineating de novo and acquired resistance mechanisms are essential for the future clinical development of MEK inhibitors. We discuss the clinical experience with MEK inhibitors to date, and consider the novel approaches to MEK-inhibitor therapy that might improve outcomes and lead to the wider use of such treatments.

New strategies in neuroblastoma: Therapeutic targeting of MYCN and ALK

Clinical outcome remains poor in patients with high-risk neuroblastoma, in which chemoresistant relapse is common following high-intensity conventional multimodal therapy. Novel treatment approaches are required. Although recent genomic profiling initiatives have not revealed a high frequency of mutations in any significant number of therapeutically targeted genes, two exceptions, amplification of the MYCN oncogene and somatically acquired tyrosine kinase domain point mutations in anaplastic lymphoma kinase (ALK), present exciting possibilities for targeted therapy. In contrast with the situation with ALK, in which a robust pipeline of pharmacologic agents is available from early clinical use in adult malignancy, therapeutic targeting of MYCN (and MYC oncoproteins in general) represents a significant medicinal chemistry challenge that has remained unsolved for two decades. We review the latest approaches envisioned for blockade of ALK activity in neuroblastoma, present a classification of potential approaches for therapeutic targeting of MYCN, and discuss how recent developments in targeting of MYC proteins seem to make therapeutic inhibition of MYCN a reality in the clinic.

Emerging options for the management of non-small cell lung cancer

Lung cancer is one of the leading causes of death in industrialized and developing countries. Approximately 80% of patients are diagnosed with non-small cell histology. Although a multidisciplinary approach is necessary for the treatment of patients at early or locally-advanced stages of the disease, further successes in the treatment of patients with advanced disease will largely rely on improved systemic tumor control. Although therapies directed against the epidermal growth factor receptor (EGFR) have been incorporated into daily clinical practice, the value of other treatments remains to be elucidated. The current review highlights the most important driver mutations in non-small cell lung cancer (NSCLC) and describes recent study results and the status of EGFR-directed therapy, anaplastic lymphoma kinase (ALK)-directed agents, antiangiogenic therapy, and mesenchymal-epithelial transition factor (MET) inhibitors. However, many other agents with different modes of action are being examined in clinical research.

Second-Line Therapy for Advanced NSCLC

Most patients with lung cancer have non-small cell lung cancer (NSCLC) subtype and have advanced disease at the time of diagnosis. Improvements in both first-line and subsequent therapies are allowing longer survival and enhanced quality of life for these patients. The median overall survival observed in many second-line trials is approximately 9 months, and many patients receive further therapy after second-line therapy. The cytotoxic agents pemetrexed and docetaxel and the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) erlotinib and gefitinib are standard second-line therapies. For patients with EGFR mutation, a TKI is the favored second-line therapy if not already used in first-line therapy. For patients without the EGFR mutation, TKIs are an option, but many oncologists favor cytotoxic therapy. The inhibitor of the EML4/ALK fusion protein, crizotinib, has recently become a standard second-line treatment for patients with the gene rearrangement and has promise for patients with the ROS1 rearrangement.

Potential therapies for anaplastic lymphoma kinase-driven tumors in children: progress to date

Anaplastic lymphoma kinase (ALK) is an oncogenic tyrosine kinase that is deregulated due to a variety of molecular mechanisms in pediatric cancer. They include chromosomal translocations, activation mutations, and gene amplifications. Since the initial discovery of ALK as an oncogenic tyrosine kinase involved in the chromosomal translocation t(2, 5)(p23;q35) in 1994, more than 20 translocation partners of ALK have been identified in various cancers. Furthermore, deregulation of ALK tyrosine kinase activity is critical for the pathogenesis of several other pediatric tumors, including neuroblastomas and inflammatory myofibroblastic tumors. The recent discovery of ALK translocations in adult lung cancer patients (non-small cell lung cancer) has accelerated the development of inhibitors of ALK tyrosine kinase as therapeutic agents. While excellent clinical response has been observed in many patients, the acquisition of clinical resistance to ALK inhibition highlights the need for development of second-generation ALK kinase inhibitors and/or combination therapies that target downstream signaling mediators or antibody drug conjugates. This article provides an update on the spectrum of ALK-driven tumors in the pediatric population and the potential therapies which target these tumors.

Emerging drugs for neuroblastoma

INTRODUCTION

Neuroblastoma accounts for 8 - 10% of pediatric cancers and is responsible for 15% of childhood cancer deaths. Despite multimodality treatment, the overall survival (OS) and event-free survival (EFS) in high-risk patients remain suboptimal. More than half of children diagnosed with high-risk neuroblastoma either do not respond to conventional therapies or relapse after treatment.

AREAS COVERED

This review discusses about the unmet medical needs for new therapeutic options against high-risk neuroblastoma. New drugs and therapeutic strategies that are under development in clinical trials, which are currently recruiting patients.

EXPERT OPINION

There is a need to improve the response rate of induction chemotherapy, which is not effective in a third of patients and also the other components of the current treatment, little efficacious in avoiding the relapses. Few drugs have been introduced as upfront therapy in the last years. Topotecan, irinotecan and temozolomide are expected to improve the response in high-risk neuroblastoma, but their impact on OS and EFS is unknown. Anti-GD2 antibodies combined with other immunomodulators (IL-2, GM-CSF) are an important advance in the treatment of these children. Nevertheless, the hope is put in the new drugs directed to molecular targets of neuroblastoma. Anti-angiogenic drugs, ALK antagonist and PI3K/Akt/mTOR inhibitors are among the most promising.

ALK in lung cancer: past, present, and future

In 2007, scientists discovered that anaplastic lymphoma kinase (ALK) gene rearrangements are present in a small subset of non-small-cell lung cancers. ALK-positive cancers are highly sensitive to small-molecule ALK kinase inhibitors, such as crizotinib. Phase I and II studies of crizotinib in ALK-positive lung cancer demonstrated impressive activity and clinical benefit, leading to rapid US Food and Drug Administration approval in 2011. Although crizotinib induces remissions and extends the lives of patients, cures are not achieved as resistance to therapy develops. In this review, we will discuss the history of this field, current diagnostic and treatment practices, and future challenges and opportunities to advance outcomes for patients with ALK-positive lung cancers.

Overcoming acquired resistance to kinase inhibition: the cases of EGFR, ALK and BRAF

In the past decade, several kinase inhibitors have been approved based on their clinical benefit for cancer patients. Unfortunately, in many cases, patients develop resistance to these agents via secondary mutations and alternative mechanisms. This review will focus on the cases of acquired resistance to EGFR and ALK inhibitors for non-small cell lung cancer patients and BRAF inhibitors for melanoma patients. I will overview the main causes of acquired resistance, and explore the chemical scaffolds as well as combination of drugs, used to tackle these major causes of resistance.

Personalized targeted therapy for lung cancer

Lung cancer has long been recognized as an extremely heterogeneous disease, since its development is unique in every patient in terms of clinical characterizations, prognosis, response and tolerance to treatment. Personalized medicine refers to the use of markers to predict which patient will most likely benefit from a treatment. In lung cancer, the well-developed epidermal growth factor receptor (EGFR) and the newly emerging EML4-anaplastic lymphoma kinase (ALK) are important therapeutic targets. This review covers the basic mechanism of EGFR and EML4-ALK activation, the predictive biomarkers, the mechanism of resistance, and the current targeted tyrosine kinase inhibitors. The efficacy of EGFR and ALK targeted therapies will be discussed in this review by summarizing the prospective clinical trials, which were performed in biomarker-based selected patients. In addition, the revolutionary sequencing and systems strategies will also be included in this review since these technologies will provide a comprehensive understanding in the molecular characterization of cancer, allow better stratification of patients for the most appropriate targeted therapies, eventually resulting in a more promising personalized treatment. The relatively low incidence of EGFR and ALK in non-Asian patients and the lack of response in mutant patients limit the application of the therapies targeting EGFR or ALK. Nevertheless, it is foreseeable that the sequencing and systems strategies may offer a solution for those patients.