Safety, Tolerability, and Pharmacokinetics of Multiple Repeated Oral Doses of the α2/3/5-Subtype Selective GABAA -Positive Allosteric Modulator PF-06372865 in Healthy Volunteers

Clin Pharmacol Drug Dev. 2021 Jul;10(7):756-764. doi: 10.1002/cpdd.912. Epub 2021 Jan 19.

Abstract

Multiple-dose pharmacokinetics (PK) and safety were investigated in this phase 1 study of PF-06372865, a positive allosteric modulator of α2/3/5 subunit-containing γ-aminobutyric acid A receptors (NCT03351751). In 2 cohorts (7-8 PF-06372865 and 2 placebo in each cohort), healthy adult subjects received twice-daily oral doses of PF-06372865 for 21 days, which included titration in the first 7 days, followed by a maintenance dose of 25 mg twice daily (Cohort 1) and 42.5 mg twice daily (Cohort 2) for 14 days. Serial PK samples were collected on days 1 and 21. Nineteen subjects were assigned to study treatments; 18 completed the study. Approximate dose-proportional increases in maximum plasma concentratin and area under the plasma concentration-time curve over the dosing interval were observed. PF-06372865 was rapidly absorbed with a median time to maximum concentration of 1 to 2 hours following both single- and multiple-dose administration. Mean terminal elimination half-life on day 21 was approximately 11 hours in both cohorts. All adverse events were mild; the most frequently reported was dizziness. After titration, there were no reports of somnolence. There were no clinically significant safety findings, including a lack of withdrawal symptoms on discontinuation of treatment. These results demonstrate that PF-06372865 is safe and well tolerated at doses estimated to achieve high receptor occupancy (>80%), a profile differentiated from nonselective benzodiazepines.

Keywords: CVL-865; GABA; GABAA; PF-06372865; epilepsy.

Publication types

  • Clinical Trial, Phase I
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Adult
  • Area Under Curve
  • Cohort Studies
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Female
  • GABA Modulators / administration & dosage*
  • GABA Modulators / adverse effects
  • GABA Modulators / pharmacokinetics
  • Half-Life
  • Humans
  • Imidazoles / administration & dosage*
  • Imidazoles / adverse effects
  • Imidazoles / pharmacokinetics
  • Male
  • Middle Aged
  • Pyridazines / administration & dosage*
  • Pyridazines / adverse effects
  • Pyridazines / pharmacokinetics

Substances

  • GABA Modulators
  • Imidazoles
  • PF-06372865
  • Pyridazines