Targeting the insulin-like growth factor axis for the development of novel therapeutics in oncology

Insulin-like growth factors (IGF) are polypeptide hormones with potent anabolic and mitogenic effects that regulate cell growth and differentiation. Dysregulation of the IGF axis has been well documented in the development and progression of multiple types of cancer. As a result, compounds targeting the IGF axis have become an area of intense preclinical and clinical research for cancer therapeutics. The IGF axis is intimately involved with the insulin-signaling pathway because of their close homologies. This homology may explain hurdles encountered in the clinical development of IGF-targeted therapies, such as less-than-expected antitumor efficacy that may arise from compensatory increases in the activity of insulin receptor isoform A (IR-A), in response to IGF-I receptor (IGF-IR) inhibition and perturbations in glucose homeostasis, arising from the inhibition of insulin receptor isoform B (IR-B) activity. In this brief review, we compare differentiating factors that characterize the 3 major classes of IGF-targeting compounds: therapeutic antibodies that target IGF-IR, small molecule tyrosine kinase inhibitors that inhibit kinase activities of IGF-IR and IR, and antibodies that target IGF ligands.

Current and emerging medical treatments for non-small cell lung cancer: a primer for pulmonologists

Pulmonary physicians commonly develop relationships with lung cancer patients through the evaluation and staging of the disease prior to the discussion of treatment options with oncologists. Given the relationship that develops, a pulmonologist is often asked about aspects of the treatment plan that may be slightly outside of their comfort zone. The aim of this overview of medical treatment of non-small cell lung cancer is to provide the pulmonologist with an overview of the evidence guiding current practice so that they can be more comfortable answering their patients' questions while awaiting the expert opinion of the oncologist. We discuss standard chemotherapeutic agents, their common side effects, and their use in the adjuvant and neoadjuvant setting, as definitive therapy for locally advanced disease, as palliative therapy for advanced disease, and as maintenance therapy. We also discuss the mechanisms of action and side effects of targeted therapies (including inhibitors of vascular endothelial growth factor [VEGF], epidermal growth factor receptor [EGFR] signaling and the anaplastic lymphoma kinase [ALK] protein), their currently accepted uses, and upcoming phase III trials, the results of which may influence standard practice.

The role of the insulin-like growth factor signaling pathway in non-small cell lung cancer and other solid tumors

The type 1 insulin-like growth factor receptor (IGF-1R) and its downstream signaling components have become increasingly recognized as having a driving role in the development of malignancy, and consequently IGF-1R has become a potential target for cancer therapy. Several inhibitors of IGF-1R are in clinical development for the treatment of solid tumors, including non-small cell lung cancer (NSCLC). These IGF-1R-targeted agents include monoclonal antibodies such as cixutumumab (IMC-A12), AMG-479, AVE1642, BIIB022, dalotuzumab (MK-0646), and robatumumab (Sch717454), the ligand neutralizing antibody Medi-573, and the small molecule inhibitors BMS-754807, linsitinib (OSI-906), XL228, and AXL1717. Two phase III trials of the anti-IGF-1R monoclonal antibody, figitumumab (CP-751,871), were discontinued in 2010 as it was considered unlikely either trial would meet their primary endpoints. In light of disappointing clinical data with figitumumab and other targeted agents, it is likely that the use of molecular markers will become important in predicting response to treatment. This review outlines the role of IGF-1R signaling in solid tumors with a particular focus on NSCLC, and provides an overview of clinical data.