Patient-centric microsampling for abrocitinib pharmacokinetics: multiple-analytes assay bridging using Tasso device

<b>Aim:</b> The feasibility of using Tasso devices (Tasso-SST^® and Tasso⁺) collecting capillary blood samples for measuring abrocitinib and its metabolites were evaluated, and assay concordance established between capillary and venous blood samplings. <b>Methods:</b> Capillary serum and venous plasma concentrations were measured using their respective qualified and validated assays. Concentration and exposure comparisons were conducted for abrocitinib and its metabolites (M1, M2 and M4) to establish assay concordance. <b>Results:</b> The correlation coefficient between capillary serum and venous plasma concentrations were &gt;0.98 for all four analytes from three separate assays, and PK parameters (AUC_last and C_max) were compared and met bioequivalence criteria. <b>Conclusion:</b> These results demonstrate the feasibility of patient-centric microsampling device, such as Tasso, in future abrocitinib pediatric study. To evaluate feasibility, the Tasso serum collection microsampling devices were used parallel to venous plasma collection in abrocitinib clinical study. The serum to plasma partial validations were conducted to ensure equivalence between serum and plasma methods. Capillary serum to venous plasma concentration bridging were conducted for abrocitinib and three major metabolites (M1, M2 and M4) per currently available industry white paper. The PK exposure comparison was conducted to demonstrate similarity in concentrations data generated using the two blood collection methods (Tasso vs. traditional venous phlebotomy). Excellent concordance between the two sets of concentrations was demonstrated for all four analytes. For abrocitinib and metabolites pharmacokinetic measurement, Tasso liquid blood microsampling device is less invasive, uses lower blood volume and can be easily implemented at clinical site in pediatric study without the complication of blood-to-plasma ratio determination.