A Validated DBS Method for Quantitation of a Novel Mutant IDH1/2 Inhibitor, Vorasidenib Using 10 μL Mice Blood: Application to a Pharmacokinetic Study in Mice

Background: Vorasidenib is a pan-IDH inhibitor, undergoing clinical trials for the treatment of acute myeloid leukemia. Methods: In this paper, we present the data of method validation to quantify vorasidenib in the mice blood mice using dried blood spot (DBS) method on LC-MS/MS as per FDA bioanalytical method validation guideline. Using methanol (enriched with internal standard) as an extraction solvent followed by sonication, vorasidenib was extracted from DBS quality control samples, calibration curve samples and pharmacokinetic study samples. Baseline separation of vorasidenib and the IS in a 2.0 μL injected sample was accomplished by delivering 0.2% formic acid and acetonitrile (25:75, v/v) at a constant flowrate (1.00 mL/min) on a C18 column. The total run time was 2.0 min. Using the transition pair of m/z 415.4→260.4 for vorasidenib and m/z 583.1→186.1 for the IS, the quantitation was performed. The method linearity range was 1.00-3008.00 ng/mL. Results: The recovery of vorasidenib ranged between 71.28%-78.14% across the tested concentrations. No matrix effect was seen. Intra- and inter-day precisions were ≤7.23% and intra- and inter-accuracies ranged between 97.1%-107%. Vorasidenib was stable for three freeze/thaw cycles, up to 7 days at room temperature and for one month at -80°C. Following intravenous and oral administration of vorasidenib to mice, it was quantifiable up to 72 h. The oral bioavailability was 51.6%. Conclusion: All the validation parameters met the acceptance criteria as specified in the FDA regulatory guideline. The results suggest that validated DBS method can be used for pharmacokinetic studies in mice to characterize the pharmacokinetic parameters of vorasidenib post intravenous and oral administration.