Simultaneous quantification of triazolam and its metabolites in human urine by liquid chromatography-tandem mass spectrometry

A simple, simultaneous, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for the determination of triazolam and its metabolites, α-hydroxytriazolam (α-OHTRZ) and 4-hydroxytriazolam (4-OHTRZ), in human urine was developed and validated. Triazolam-d4 was used as the internal standard (IS). This analysis was carried out on a Thermo(?) C(18) column, and the mobile phase was composed of acetonitrile/H(2)O/formic acid (35:65:0.2, v/v/v). Detection was performed on a triple-quadrupole tandem MS using positive ion mode electrospray ionization, and quantification was performed by multiple reaction monitoring mode. The MS-MS ion transitions monitored were m/z 343.1 → 308.3, 359.0 → 331.0, 359.0 → 111.2, and 347.0 → 312.0 for triazolam, α-OHTRZ, 4-OHTRZ, and triazolam-d(4), respectively. The lower limits of quantification of the analytical method were 0.5 ng/mL for triazolam, 5 ng/mL for α-OHTRZ, and 0.5 ng/mL for 4-OHTRZ. The within- and between-run precisions were less than 15%, and accuracy was -12.33% to 9.76%. The method was proved to be accurate and specific, and it was applied to a urinary excretion study of triazolam in healthy Chinese volunteers.     

Evolutionary modeling of combination treatment strategies to overcome resistance to tyrosine kinase inhibitors in non-small cell lung cancer

Many initially successful anticancer therapies lose effectiveness over time, and eventually, cancer cells acquire resistance to the therapy. Acquired resistance remains a major obstacle to improving remission rates and achieving prolonged disease-free survival. Consequently, novel approaches to overcome or prevent resistance are of significant clinical importance. There has been considerable interest in treating non-small cell lung cancer (NSCLC) with combinations of EGFR-targeted therapeutics (e.g., erlotinib) and cytotoxic therapeutics (e.g., paclitaxel); however, acquired resistance to erlotinib, driven by a variety of mechanisms, remains an obstacle to treatment success. In about 50% of cases, resistance is due to a T790M point mutation in EGFR, and T790M-containing cells ultimately dominate the tumor composition and lead to tumor regrowth. We employed a combined experimental and mathematical modeling-based approach to identify treatment strategies that impede the outgrowth of primary T790M-mediated resistance in NSCLC populations. Our mathematical model predicts the population dynamics of mixtures of sensitive and resistant cells, thereby describing how the tumor composition, initial fraction of resistant cells, and degree of selective pressure influence the time until progression of disease. Model development relied upon quantitative experimental measurements of cell proliferation and death using a novel microscopy approach. Using this approach, we systematically explored the space of combination treatment strategies and demonstrated that optimally timed sequential strategies yielded large improvements in survival outcome relative to monotherapies at the same concentrations. Our investigations revealed regions of the treatment space in which low-dose sequential combination strategies, after preclinical validation, may lead to a tumor reduction and improved survival outcome for patients with T790M-mediated resistance.     

Optimization of dosing for EGFR-mutant non-small cell lung cancer with evolutionary cancer modeling

Non-small cell lung cancers (NSCLCs) that harbor mutations within the epidermal growth factor receptor (EGFR) gene are sensitive to the tyrosine kinase inhibitors (TKIs) gefitinib and erlotinib. Unfortunately, all patients treated with these drugs will acquire resistance, most commonly as a result of a secondary mutation within EGFR (T790M). Because both drugs were developed to target wild-type EGFR, we hypothesized that current dosing schedules were not optimized for mutant EGFR or to prevent resistance. To investigate this further, we developed isogenic TKI-sensitive and TKI-resistant pairs of cell lines that mimic the behavior of human tumors. We determined that the drug-sensitive and drug-resistant EGFR-mutant cells exhibited differential growth kinetics, with the drug-resistant cells showing slower growth. We incorporated these data into evolutionary mathematical cancer models with constraints derived from clinical data sets. This modeling predicted alternative therapeutic strategies that could prolong the clinical benefit of TKIs against EGFR-mutant NSCLCs by delaying the development of resistance.     

A new target for therapy in squamous cell carcinoma of the lung

Investigators report the identification of novel somatic mutations in the DDR2 kinase gene in squamous cell carcinoma of the lung. Cellular, biochemical, and human data suggest that tumor cells harboring DDR2 mutations have increased sensitivity to existing tyrosine kinase inhibitors, providing rationale for clinical trials of agents that inhibit DDR2 kinase in the disease.     

Medication compliance and clinical outcomes of fixed‐dose combinations vs free combinations of an angiotensin II receptor blocker and a calcium channel blocker in hypertension treatment

Using the National Health Insurance Research Database of Taiwan, the authors identified 1136 patients taking fixed‐dose combination and 4544 patients taking free combinations of an angiotensin II receptor blocker and a dihydropyridine calcium channel blocker from January 2009 to December 2012. At a mean follow‐up of 2.1 years, the fixed‐dose combination was associated with improved medication adherence and persistence and better survival free from major adverse cardiac events and hospitalization for heart failure compared with the free combination regimens.