Recent Developments and Challenges in Molecular-Targeted Therapy of Non-Small-Cell Lung Cancer

Treatment of lung cancer with conventional therapies, which include radiation, surgery, and chemotherapy results in multiple undesirable adverse or side effects. The major clinical challenge in developing new drug therapies for lung cancer is resistance, which involves mutations and disturbance in various signaling pathways. Molecular abnormalities related to epidermal growth factor receptor (EGFR), v-Raf murine sarcoma viral oncogene homolog B1 (B-RAF) Kirsten rat sarcoma virus (KRAS) mutations, translocation of the anaplastic lymphoma kinase (ALK) gene, mesenchymal-epithelial transition factor (MET) amplification have been studied to overcome the resistance and to develop new therapies for non-small cell lung cancer (NSCLC). But, inevitable development of resistance presents limits the clinical benefits of various new drugs. Here, we review current progress in the development of molecularly targeted therapies, concerning six clinical biomarkers: EGFR, ALK, MET, ROS-1, KRAS, and B-RAF for NSCLC treatment.

Pathway Targeted Immunotherapy: Rationale and Evidence of Durable Clinical Responses with a Novel, EGF-directed Agent for Advanced NSCLC

Abnormalities in the epidermal growth factor (EGF) and EGFR pathway promote progression of NSCLC. Immunization with EGF vaccine induces specific, neutralizing anti-EGF antibodies that prevent binding of the ligand to its receptor. This concept of pathway targeted immunotherapy (PTI) was validated in vitro by dose-related suppression of EGFR, Akt, and Erk1/2 phosphorylation in cell lines with different mutations. A randomized phase II trial showed improved overall survival (OS) in subgroups with advanced NSCLC showing a clear immunologic response. By per-protocol analysis of the ensuing phase IIb trial, patients receiving EGF PTI survived 3 months longer than controls (12.43 versus 9.43 months; hazard ratio = 0.77 [95% confidence interval, 0.61-0.98]). These data were confirmed in a larger trial showing an OS benefit over control of >3 months. The variable most strongly correlated with efficacy was circulating EGF at enrolment. Patients with serum EGF levels >250 pg/mL benefited most from treatment with EGF PTI. Of 188 patients tested, 94 were above this biomarker threshold. The OS benefit from active versus control treatment was 6.7 months. More than 15% of patients had responses for >5 years. Long-term survivors are seen in all EGF PTI trials. Treatment is well-tolerated, induces high anti-EGF antibody titers, reduces levels of circulating serum EGF, achieves durable responses, and significantly prolongs OS. A threshold of 250 pg/mL has been set to enrich the study population in the ongoing pivotal trial. This biomarker-guided study in an enriched population of patients with both squamous and nonsquamous stage IV NSCLC aims to replicate the favorable efficacy/tolerability balance of earlier studies.

Immunotherapy Comes of Age in Lung Cancer

Lung carcinoma is the leading cause of death by cancer worldwide. When possible, surgery is the best treatment strategy for patients with non-small-cell lung cancer. However, even with curative-intent therapy, most patients will develop local or systemic recurrence and, ultimately, succumb to their disease. In recent years, evidence on the role of the antitumor activity of the immune system and the understanding of tumor immunosurveillance have resulted in the emergence of immunotherapy as a promising therapeutic approach in lung cancer. The main approaches are immune checkpoint inhibition, such as blockade of the cytotoxic T-lymphocyte antigen-4 and programmed cell death-1 receptors and the programmed cell death-1 ligand, and vaccine therapy, which elicits specific antitumor immunity against relevant tumor-associated antigens. We have reviewed recently reported results from clinical trials and the possible future role of vaccine therapy and immune checkpoint inhibition in the treatment of small cell lung cancer and non-small-cell lung cancer.

The future of immunotherapy in the treatment of lung cancer

SUMMARY 

Despite advances in the understanding of the genetic and nongenetic mechanisms involved in driving the development of lung cancers, mortality from lung cancer remains very poor. Detection and recognition of pathogens as being foreign and the facilitation of their destruction is the fundamental role of the immune system. Recent approval for the use of immunotherapeutics in the treatment of melanoma and prostate cancer, and emerging evidence of the interplay between malignant cells and the host immune response in recognizing them have led to a new focus in the treatment of lung cancer. Such strategies include vaccination therapies and immune checkpoint blockade, many of which have reached Phase III trials but with modest translation to clinical benefit. This article looks at the biology and current clinical data in the use of these immunological agents.

[Development of an immunochromatographic test system for the detection of human enidermal growth factor]

A method was developed for the rapid detection of human epidermal growth factor based on a sandwich-format immunochromatographic assay. The contact between the sample and the test strip with immobilized immunoreagents initiates the fluid flow movement across the membrane components of the test strip, immunochemical reactions, and the formation of colored lines. Requirements on the configuration of the test system in order to achieve the lowest limit of detection were defined in the course of the development of the assay. It was shown that this method enables the detection of human epidermal growth factor within 5 min at concentrations as low as 10 pg/mL in aqueous solutions, urine, and the blood serum and plasma. The developed test system can be used for point-of-care diagnostics.

Immunotherapy in lung cancer

Survival rates for metastatic lung cancer including non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) are poor with 5-year survival of less than 5%. The use of molecular targeted therapies has improved median overall survival (OS) in a limited group of NSCLC patients whose tumors harbor specific genetic alterations. However for a large group of NSCLC and SCLC molecular alterations are not available to lead to direct targeted therapies. Recent favorable results of newer trials of therapeutic vaccines and checkpoint inhibitors have proven against the common belief that lung cancer is nonimmunogenic. In particular, the checkpoint inhibitors targeting cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and the programmed death-1 (PD-1) pathway have shown durable clinical responses with manageable toxicity. Several phase II and III clinical trials testing the association of different schedule of chemotherapy and immunotherapy or immunotherapy alone are ongoing in lung cancer and important results are expected in the near future. However, more studies are needed to understand the optimal combination of immunotherapeutic agents with chemotherapy and radiation therapy for the treatment of NSCLC and SCLC.

What lies within: novel strategies in immunotherapy for non-small cell lung cancer

Immunotherapy has become an increasingly important therapeutic strategy for those with cancer, with phase III studies demonstrating survival advantages in melanoma and castration-resistant prostate cancer. Non-small cell lung cancer (NSCLC) is a promising target for the next generation of immune-based strategies. In this article, we examine the current state of the art in lung cancer immunotherapy, including vaccines that specifically target lung tumor antigens and immune checkpoint antibodies such as antiprogrammed death 1 (anti-PD-1). Both approaches harness innate immunity against tumors by suppressing tumor-induced immune paresis. Methods. To identify relevant clinical trials of immunotherapy in NSCLC, PubMed and Medline databases were searched using the terms "immunotherapy" and "NSCLC," and several other therapy-specific search terms (e.g., PD-1, NSCLC). Additionally, abstracts presented at international lung cancer symposia, the American Society of Clinical Oncology annual meeting, and the European Society of Medical Oncology annual meeting between 2005 and 2013 were evaluated. Results. Large international phase III trials of NSCLC vaccines have completed accrual in both the adjuvant and metastatic disease settings. Results of the START study were disappointing, but results from other studies are still awaited. Immune checkpoint modulation has shown promise, with separate phase I studies of the anti-PD-1 antibody, nivolumab, and anti-PD-L1 antibody, MPDL3280A, demonstrating good tolerance and durable responses for certain patients with NSCLC who were heavily pretreated. Conclusions. Immune-based strategies have shown initial promise for early- and advanced-stage NSCLC. Validating these findings in randomized studies and discovering durable biomarkers of response represent the next challenges for investigation.