The phosphoinositide 3-kinase-AKT-mammalian target of rapamycin (PI3K-AKT-mTOR) pathway is a frequently hyperactivated pathway in cancer and is important for tumor cell growth and survival. The development of targeted therapies against mTOR, a vital substrate along this pathway, led to the approval of allosteric inhibitors, including everolimus and temsirolimus, for the treatment of breast, renal, and pancreatic cancers. However, the suboptimal duration of response in unselected patients remains an unresolved issue. Numerous novel therapies against critical nodes of this pathway are therefore being actively investigated in the clinic in multiple tumor types. In this review, we focus on the progress of these agents in clinical development along with their biological rationale, the need of predictive biomarkers and various combination strategies, which will be useful in counteracting the mechanisms of resistance to this class of drugs.
Antineoplastic Agents ; therapeutic use ; Drug Resistance, Neoplasm ; Humans ; Molecular Targeted Therapy ; Neoplasms ; drug therapy ; genetics ; metabolism ; PTEN Phosphohydrolase ; genetics ; metabolism ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; metabolism ; Proto-Oncogene Proteins c-akt ; antagonists & inhibitors ; metabolism ; Proto-Oncogene Proteins c-ret ; metabolism ; Sirolimus ; therapeutic use ; TOR Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism

Despite recent improvements to current therapies and the emergence of novel agents to manage advanced non-small cell lung cancer (NSCLC), the patients' overall survival remains poor. Re-challenging with first-line chemotherapy upon relapse is common in the management of small cell lung cancer but is not well reported for advanced NSCLC. NSCLC relapse has been attributed to acquired drug resistance, but the repopulation of sensitive clones may also play a role, in which case re-challenge may be appropriate. Here, we report the results of re-challenge with gemcitabine plus carboplatin in 22 patients from a single institution who had previously received gemcitabine plus platinum in the first-line setting and had either partial response or a progression-free interval of longer than 6 months. In this retrospective study, the charts of patients who underwent second-line chemotherapy for NSCLC in our cancer center between January 2005 and April 2010 were reviewed. All the patients who received a combination of gemcitabine and carboplatin for re-challenge were included in the study. These patients were offered second-line treatment on confirmation of clear radiological disease progression. The overall response rate was 15% and disease control rate was 75%. The median survival time was 10.4 months, with 46% of patients alive at 1 year. These results suggest that re-challenge chemotherapy should be considered in selected patients with radiological partial response or a progression-free survival of longer than 6 months to the initial therapy.
Adult ; Aged ; Aged, 80 and over ; Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Carboplatin ; administration & dosage ; Carcinoma, Non-Small-Cell Lung ; drug therapy ; pathology ; Deoxycytidine ; administration & dosage ; analogs & derivatives ; Disease Progression ; Disease-Free Survival ; Female ; Follow-Up Studies ; Humans ; Lung Neoplasms ; drug therapy ; pathology ; Male ; Middle Aged ; Neoplasm Staging ; Remission Induction ; Retrospective Studies ; Survival Rate