The Pharmacokinetic Profile of Palovarotene: An Open-Label Phase I Trial Investigating the Effect of Food and Potential for Drug-Drug Interaction in Healthy Participants.

Background and objectives: Palovarotene is under development for the treatment of fibrodysplasia ossificans progressiva (FOP). The objectives of this study were to evaluate palovarotene pharmacokinetics under fed versus fasted conditions and its induction potential towards cytochrome P450 3A4 (CYP3A4) substrate, midazolam.

Methods: In this phase I, open-label trial (NCT04829773), palovarotene pharmacokinetics were characterized after repeated once-daily dosing. In one cohort, healthy participants received three doses of palovarotene 20 mg on Days 1, 6, and 11, as whole capsules under fasted or fed conditions, or sprinkled on food under fed conditions. In another cohort, individuals received midazolam 2 mg on Days 1 and 15 and a daily dose of palovarotene 20 mg on Days 2-15. Palovarotene and midazolam pharmacokinetics, including area under the concentration-time curve from time zero to infinity (AUC_(0-∞)) and maximum observed plasma drug concentration (C_max), were assessed. Adverse events (AEs) were recorded.

Results: Overall, 23 participants completed each part. Palovarotene C_max and AUC_(0-∞) increased by 16.5% and 39.7% under fed versus fasted conditions. Pharmacokinetics were comparable between the whole capsule and sprinkled on food, under fed conditions. Midazolam AUC_(0-∞) and C_max decreased by 13.3% and 9.7% upon palovarotene co-administration over 14 days, less than that required to be considered a weak CYP3A4 inducer. Plasma palovarotene exposures were comparable after single and multiple doses. No serious AEs were reported.

Conclusions: These data support palovarotene administration after a meal, as a whole capsule or sprinkled on food. Palovarotene at 20 mg/day is a not a clinical inducer of CYP3A4. These results provide insights into palovarotene pharmacokinetics, aiding optimization of administration for patients with FOP.

Clinical trials registration number: NCT04829773.