Wide-range and high-throughput quantification of anamorelin in human plasma using ultra-high-performance liquid...

Cancer cachexia is characterized by weight loss, muscle mass loss, and reduced food intake. Anamorelin is a ghrelin receptor agonist approved for the treatment of cancer cachexia. In this study, we established and validated an assay for quantification of anamorelin in human plasma.

For quantification of anamorelin, samples were pretreated with solid-phase extraction and analyzed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). This analytical method was validated in accordance with the Food and Drug Administration (FDA) bioanalytical method validation guidance. We used the established assay to quantify plasma anamorelin concentrations in five patients with cancer cachexia treated with anamorelin.

The validation results of this assay method met the acceptance criteria recommended by the FDA guidance. Within-batch and batch-to-batch precision at the lower limit of quantification and three quality control levels were within 6.20 % and 6.55 % coefficient of variation, respectively. Within-batch and batch-to-batch accuracies ranged from -2.58 to -1.33 % and -3.78 to -1.69 %, respectively. Recovery rates and matrix effects corrected by internal standard were 82.7-84.2 % and 102.7-104.6 %, respectively. Using the established assay with a calibration range of 0.1-2500 ng/mL, plasma anamorelin concentrations were successfully quantified in all 15 plasma samples from 5 patients with cancer cachexia.

We established and validated a method to measure plasma anamorelin concentrations using UHPLC/MS-MS combined with SPE, and successfully applied the novel method to measure plasma anamorelin concentrations in patients with cancer cachexia. By measuring plasma anamorelin concentrations in large scale studies, the established quantitative method is expected to contribute to the pharmacokinetic study of anamorelin.