Determination of osimertinib in human plasma, urine and cerebrospinal fluid.

Aim: Osimertinib (Tagrisso, AZD9291) has been approved for the treatment of patients with metastatic EGFRm T790M non-small-cell lung cancer. Results: Rapid and sensitive LC-MC/MS methods were developed for osimertinib and its metabolites, AZ13597550 and AZ13575104, in human plasma (low- and high-range), urine and cerebrospinal fluid. We discuss the challenges of these multi-analyte and multiple matrix assays. The methods have been successfully validated and used for the analysis of over 20,000 clinical samples, with successful incurred sample reproducibility. Conclusion: The assays have been shown to be selective, accurate and robust, providing high-throughput analysis during the clinical development of osimertinib.

Development of an LC-MS/MS-based method for quantitation of osimertinib in human plasma and cerebrospinal fluid.

Aim: The transitivity of osimertinib to cerebrospinal fluid (CSF) is of clinical concern. A quantitative LC-MS/MS method for the determination of osimertinib in human plasma and CSF was developed to evaluate its transitivity. Results: The calibration range was 40-1000 nM in plasma and 0.8-100 nM in CSF. Accuracy and precision were within 15%. Osimertinib in the CSF but not in plasma strongly adsorbed onto the storage container. The mean adsorbed loss of osimertinib was 45.5% in CSF. Nonspecific binding in CSF was decreased by protein addition (mean loss = 5.8%). Conclusion: A robust validated method was developed for the quantification of osimertinib in human plasma and CSF.

Osimertinib Quantitative and Gene Variation Analyses in Cerebrospinal Fluid and Plasma of a Non-small Cell Lung Cancer Patient with Leptomeningeal Metastases.

BACKGROUND: Leptomeningeal metastases (LM) are much more frequent in patients of non-small lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. Osimertinib, a third-generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFRTKI) shows promising efficacy for LM. OBJECTIVE: The aim of this study was to analyze the concentration of osimertinib and gene variation of circulating tumor DNA (ctDNA) in human plasma and cerebrospinal fluid (CSF). Furthermore, we explored whether ctDNA in CSF might be used as a biomarker to predict and monitor therapeutic responses. METHODS: The dynamic paired CSF and blood samples were collected from the NSCLC patient with LM acquired EGFR-TKI resistance. A method based on ultra-high performance liquid chromatography- tandem mass spectrometry (UPLC-MS/MS) was developed and validated for detecting osimertinib in CSF and plasma samples. Gene variations of ctDNA were tested by next-generation sequencing with a panel of 1021 genes. RESULTS: The concentrations of osimertinib in CSF were significantly lower than that in plasma (penetration rate was 1.47%). Mutations included mTOR, EGFR, CHECK1, ABCC11, and TP53 were explored in ctDNA from plasma and CSF samples. The detected mutation rate of CSF samples was higher than that of plasma samples (50% vs. 25%). Our data further revealed that the variations allele frequency (VAF) and molecular tumor burden index (mTBI) of ctDNA derived from CSF exhibited the negative correlation with efficacy of treatment. CONCLUSION: ctDNA from CSF might be a useful biomarker for monitoring the efficacy of treatment and an effective complement to nuclear magnetic resonance imaging (MRI) for LM.

Dissociation between central and peripheral antihistamine activities of the new antiallergic agent N-[4-[4-(diphenylmethyl)-1-piperazinyl]-butyl]-3-(6-methyl-3-pyridyl) acrylamide in rats and monkeys.

In order to examine the penetration of N-[4-[4-(diphenylmethyl)-1-piperazinyl]-butyl]-3-(6-methyl-3-pyrid yl) acrylamide (AL-3264, CAS 118420-47-6), a new antiallergic agent, into the brain, the antihistamine activities in the central and peripheral tissues from the rats and monkeys orally treated with AL-3264 were measured in comparison with those of ketotifen, oxatomide, mequitazine and terfenadine. These 5 drugs dose-relatedly suppressed the histamine-induced dye leakage in the rat skin and, except terfenadine, inhibited the binding of 3H-mepyramine to brain homogenates obtained from the rats treated orally with the drugs. The ratio (0.07) of AL-3264 for the central (3H-mepyramine binding) to peripheral (dye leakage) antihistamine activities was lower than that of ketotifen, oxatomide and mequitazine, and higher than that of terfenadine. The serum and cerebrospinal fluid (CSF) samples, which were collected from the monkeys treated with 80 mg/kg p.o. of AL-3264, terfenadine or oxatomide, inhibited the histamine-induced contractions in isolated guinea pig trachea. The ratio (0.003) of AL-3264 for the central (CSF) to peripheral (serum) antihistamine activities was lower than that of terfenadine and oxatomide. These results suggest that AL-3264 is poorly accessible to the brain, and may be regarded as a non-sedative antiallergic agent.