Effect of R667, a novel emphysema agent, on the pharmacokinetics of midazolam in healthy men

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 (Cmax), were assessed. Adverse events (AEs) were recorded.

RESULTS

Overall, 23 participants completed each part. Palovarotene Cmax 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 Cmax 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.

Selective Retinoic Acid Receptor γ Agonists Promote Repair of Injured Skeletal Muscle in Mouse

Retinoic acid signaling regulates several biological events, including myogenesis. We previously found that retinoic acid receptor γ (RARγ) agonist blocks heterotopic ossification, a pathological bone formation that mostly occurs in the skeletal muscle. Interestingly, RARγ agonist also weakened deterioration of muscle architecture adjacent to the heterotopic ossification lesion, suggesting that RARγ agonist may oppose skeletal muscle damage. To test this hypothesis, we generated a critical defect in the tibialis anterior muscle of 7-week-old mice with a cautery, treated them with RARγ agonist or vehicle corn oil, and examined the effects of RARγ agonist on muscle repair. The muscle defects were partially repaired with newly regenerating muscle cells, but also filled with adipose and fibrous scar tissue in both RARγ-treated and control groups. The fibrous or adipose area was smaller in RARγ agonist-treated mice than in the control. In addition, muscle repair was remarkably delayed in RARγ-null mice in both critical defect and cardiotoxin injury models. Furthermore, we found a rapid increase in retinoid signaling in lacerated muscle, as monitored by retinoid signaling reporter mice. Together, our results indicate that endogenous RARγ signaling is involved in muscle repair and that selective RARγ agonists may be beneficial to promote repair in various types of muscle injuries.

Pharmacokinetics of a novel agent, R667, in patients with emphysema

AIMS

To evaluate the pharmacokinetics of R667, a novel emphysema agent, in patients with moderate to severe emphysema.

METHODS

Multiple-dose pharmacokinetics of R667 and its metabolites in emphysematous patients were studied in a multicentre, randomized, single-blind, and placebo-controlled trial. Four groups of 10 patients per group received placebo, 0.2, 0.5, or 1 mg R667 once a day for 14-16 days. On day 14 (+/-1), blood samples were taken at predose and 1, 2, 3, 4, 6, 8, 10, 12, 16 and 24 h after dosing.

RESULTS

Pharmacokinetic analysis of the data indicated that the mean steady-state C(max) and AUC(0,tau) of R667 appeared to be dose proportional over the dose range of 0.2-1 mg when administered to emphysematous patients. Mean metabolite to R667 ratios for C(max) or AUC(0,tau) were, in general, similar across the dose range of 0.2-1 mg.

CONCLUSIONS

The pharmacokinetics of R667 and its metabolites appeared to be similar for patients with emphysema and healthy volunteers. Multiple-dose administration of 0.2-1 mg of R667 for up to 16 days was well tolerated in patients with emphysema.