Pharmacokinetic Effects of QTI571 on Sildenafil and Bosentan in Pulmonary Arterial Hypertension Participants

Geometric Mean Ratio of Dose Normalized Area Under the Curve From Time Zero to Tau (AUCtau) for Bosentan Before and After Imatinib Administrations

AUCtau was the area under the curve calculated to the end of the dosing interval, tau. The effect of co-administration of imatinib at two doses (200 and 400 mg) on the pharmacokinetics of bosentan was performed on dose normalized AUCtau of bosentan. A mixed effects linear model was fitted to the log-transformed PK parameters. This model included treatment (i.e., dose of imatinib) as a fixed effect, and participant as a random effect. Estimates for the treatment differences and associated 90% confidence intervals were obtained from the above model. These estimates and confidence intervals were then "back-transformed" to the original scale, giving, for each dose level of imatinib, the ratio of imatinib + co-administered sildenafil and bosentan (test) relative to the co-administered drugs alone (sildenafil + bosentan) (reference).

Time frame: Day 1: pre-dose, Day 8: pre-dose, 0.5, 1, 2, 3, 4, 6, 8, 10 and 12 hours post-dose, Day 9: pre-dose, Days 22 and 36: pre-dose, 0.5, 1, 2, 3, 4, 6, 8, 10, 12 and 24 hours post-dose

Geometric Mean Ratio of Dose Normalized AUCtau for Sildenafil Before and After Imatinib Administrations

AUCtau was the area under the curve calculated to the end of the dosing interval, tau. The effect of co-administration of imatinib at two doses (200 and 400 mg) on the pharmacokinetics of sildenafil was performed on dose normalized AUCtau of sildenafil. A mixed effects linear model was fitted to the log-transformed PK parameters. This model included treatment (i.e., dose of imatinib) as a fixed effect, and participant as a random effect. Estimates for the treatment differences and associated 90% confidence intervals were obtained from the above model. These estimates and confidence intervals were then "back-transformed" to the original scale, giving, for each dose level of imatinib, the ratio of imatinib + co-administered sildenafil and bosentan (test) relative to the co-administered drugs alone (sildenafil + bosentan) (reference).

Time frame: Day 1: pre-dose, Day 8: pre-dose, 0.5, 1, 2, 3, 4, 6, 8, 10 and 12 hours post-dose, Day 9: pre-dose, Days 22 and 36: pre-dose, 0.5, 1, 2, 3, 4, 6, 8, 10, 12 and 24 hours post-dose

Geometric Mean Ratio of Dose Normalized Maximum Plasma Concentration (Cmax) for Bosentan Before and After Imatinib Administrations