Incorporating dried blood spot LC-MS/MS analysis for clinical development of a novel oncolytic agent.

AIM: Design and execution of a dried blood spot (DBS-LC-MS/MS) assay for pharmacokinetic analyses in oncology patients. RESULTS & DISCUSSION: The methodology was validated to collect and store DBS samples from multiple clinical sites, and analyze blood with diverse hematocrit ranges (25-55) to match the potential patient population. Bridging data comparing DBS and plasma showed high degree of concordance with DBS:plasma ratios of 0.81, demonstrating no preferential uptake or association with cellular components of the blood. Pharmacokinetic analysis supporting clinical development was performed using 20 µl of blood collected as DBS. Incurred sample reanalysis showed high correlation. CONCLUSION: Successful validation of a DBS method and implementation in the clinic enabled pharmacokinetic analysis during the clinical development of a novel oncolytic agent in oncology patients.

High sensitive assay employing column switching chromatography to enable simultaneous quantification of an amide prodrug of gemcitabine (LY2334737), gemcitabine, and its metabolite dFdU in human plasma by LC-MS/MS.

In this study we report a high sensitive method for the simultaneous analysis of LY2334737 (2'-deoxy-2',2'-difluoro-N-(1-oxo-2-propylpentyl)-cytidine), an amide prodrug of gemcitabine (2', 2'-difluoro-deoxycytidine), along with its active drug gemcitabine and its major metabolite dFdU (2',2'-difluoro-deoxyuridine) by LC-MS/MS. Quantification of all three analytes within a single analysis was challenging because the physio-chemical properties of LY2334737 were significantly different from gemcitabine and dFdU and was accomplished by incorporating column-switching. The assay was fully validated to quantify LY2334737 from 0.1 to 100ng/mL, gemcitabine from 0.25 to 100ng/mL and dFdU from 1 to 1000ng/mL in order to cover the diverse concentration ranges expected in clinical samples. A 25-fold dilution was also validated to accommodate any samples outside this range. Overall, the assay had good accuracy (ranging from -7.0 to 1.2% relative error) and precision (ranging from 2.1 to 8.4% relative standard deviation). Extraction efficiency was greater than 80% for all three analytes and there were no matrix effects. Plasma samples were stable for 24h at room temperature, 660 days in frozen storage, and at least 4 freeze-thaw cycles, at both -20 and -70°C. Data from clinical trials showed that plasma concentrations for LY2334737, gemcitabine, and dFdU were successfully quantified from a single LC-MS/MS analysis and that the assay ranges selected for the three analytes were appropriate and minimized the need for reanalysis.