This phase I, open-label, multicenter, randomized, crossover study was conducted in accordance with Good Clinical Practice, and adhered to the International Conference on Harmonization Guideline E6 and ethical principles outlined in the Declaration of Helsinki. The study received approval from relevant independent review boards or ethics committees (listed in the Supplementary Appendix) before commencement. All patients provided written informed consent. This study is registered at ClinicalTrials.gov (NCT01519011).
Study design
The trial comprised two stages:
Stage 1 evaluated the relative bioequivalence of the pharmacokinetic (PK) parameters two formulations of CC-486. Patients were randomized 1:1 to receive one dose of CC-486 either as two 150-mg tablets (Formulation A) or a single 300-mg tablet (Formulation B) in a fasted state on day 1, and then crossed over to receive one dose of the alternate CC-486 dosing regimen (also in a fasted state) after an interval of ≥ 48 h following the initial dose.
Stage 2 assessed the food effect on the bioavailability of CC-486 Formulation B. Patients were randomized 1:1 to receive the single CC-486 300-mg tablet on each of two PK study days under fed or fasted conditions, and then crossed over to receive the same 300-mg tablet formulation under the opposite (fasted or fed) condition after an interval of ≥ 48 h.
Fasted state required an overnight fast of at least 8 h, and no food was allowed for at least 2 h post-dose. Water could be taken as desired, except for 1 h before or after CC-486 administration. In the fed state, following an overnight fast, patients were to eat breakfast 30 (± 5) min before planned administration of CC-486. A high-fat (~ 50% of total caloric content) and high-calorie (~ 800–1000 cal) breakfast was consumed, comprising approximately 150, 250, and 500–600 cal from protein, carbohydrate, and fat, respectively.
Blood samples for PK assessments were collected before administration of CC-486, and at 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, and 8 h post-dose. All plasma PK samples were analyzed centrally using a validated proprietary high-performance liquid chromatography/tandem mass spectrometric method. The lower limit of quantitation for azacitidine in human plasma was 1.00 ng/mL, with linearity demonstrable to 1000 ng/mL (upper limit of quantitation). PK parameters evaluated were area under the plasma concentration–time curve from time 0 to time t (time to last measurable concentration [AUCt]) and from time 0 extrapolated to infinity (AUC∞), maximum plasma concentration (Cmax), time to Cmax (Tmax), terminal half-life (t1/2), apparent total clearance (CL/F) and volume of distribution (Vz/F).
After completing Stage 1 or Stage 2, patients could enter an extension phase of the study and receive azacitidine 75 mg/m2/day IV or SC for 7 consecutive days of repeated 28-day cycles for up to six cycles.
Statistical analyses
We chose a sample size of 54 patients in each stage (approximately 60 patients enrolled to account for ~ 10% dropout rate) to provide 90% power to conclude bioequivalence and food effect, respectively, assuming the within-patient coefficient of variation as approximately 30%. Power calculations are based on a two one-sided test procedure at the 5% significance level for bioequivalence acceptance limits (80, 125) and assumes a true mean ratio of the log-transformed PK parameters AUC∞ and Cmax between 0.95 and 1.05 when comparing the test (1 × 300 mg tablet) and reference (2 × 150 mg tablet) in the bioequivalence stage; and the test (1 × 300 mg tablet under fasted condition) and reference (1 × 300 mg tablet under fed condition) in the food effect stage. For Tmax, a non-parametric statistical method was used to compare the median Tmax between formulations A and B, and between fed vs fasted states.