Clinical development of an XXXX pediatric formulation: relative bioavailability, food effect, and steady-state pharmacokinetics.

@entity2239 @entity1
The immunosuppressant @entity2239 used in organ transplantation is formulated as a conventional tablet for adults and a dispersible tablet that can be administered in water for pediatric use. As part of the pediatric clinical development program, the relative bioavailability and food effect for the dispersible tablet were evaluated in healthy adult subjects as a prelude to characterizing the steady-state pharmacokinetics in pediatric kidney allograft recipients. In a randomized, open-label, three-way crossover study, 24 healthy adults received single 1.5-mg oral doses of @entity2239 as (1) six 0.25-mg dispersible tablets in water, (2) two 0.75-mg conventional tablets, and (3) six 0.25-mg dispersible tablets in water after a high-fat breakfast. Cmax and AUC were evaluated by standard bioequivalence testing to determine relative bioavailability and to quantify the effect of food. In a multicenter open-label efficacy/safety trial, pediatric renal allograft recipients received 0.8 mg/m2 (maximum 1.5 mg) bid @entity2239 as dispersible tablets in water. Serial trough concentrations over the first week and a steady-state pharmacokinetic profile on day 7 posttransplant were collected in 19 @entity1 ranging from ages 2 to 16 years old. The bioavailability of @entity2239 from the dispersible tablet was 10% lower relative to the conventional tablet, with a ratio (90% confidence interval) of 0.90 (0.76-1.07). After a high-fat meal, tmax was delayed by a median 2.5 hours, and Cmax was reduced by 50%. Overall absorption, however, was not affected by food inasmuch as the fed/fasting AUC ratio was 0.99 (0.83-1.17). In pediatric @entity1 , steady state was reached between days 3 and 5. The corresponding steady-state parameters were as follows: Cmin, 4.4 +/- 1.7 ng/ml; Cmax, 13.6 +/- 4.2 ng/ml; and AUC, 87 +/- 27 ng.h/ml. Steady-state concentration-time profiles in pediatric transplant @entity1 receiving the dispersible tablet were comparable to those of adult @entity1 receiving the conventional tablet when both were dosed to yield similar trough concentrations. If a pediatric @entity1 is converted from the @entity2239 dispersible tablet to the conventional tablet, this should be based on a 1:1 milligram switch with subsequent therapeutic drug monitoring to further individualize the dose as needed. The dispersible tablet formulation should be taken consistently either with or without food to minimize fluctuations in exposure over time.
