Human Abuse Potential of Oral NKTR-181 in Recreational Opioid Users: A Randomized, Double-Blind, Crossover Study.

OBJECTIVE: To evaluate the human abuse potential, pharmacokinetics, pharmacodynamics, and safety of oral NKTR-181 (oxycodegol), a novel full mu-opioid receptor agonist, relative to oral oxycodone. DESIGN: This double-blind, randomized, single-dose, crossover human abuse potential study was conducted in healthy, adult, non-physically dependent recreational opioid users. SETTING: Inpatient clinical research site. SUBJECTS: Seventy-one subjects randomized (95.7% male, 65.2% African American, mean age = 31.7 years). METHODS: The primary objective was to compare two therapeutic doses of NKTR-181 (400 and 600 mg) with 40 and 60 mg of oxycodone and a supratherapeutic dose (1200 mg) of NKTR-181 with 60 mg of oxycodone using visual analog scale (VAS) ratings for Drug Liking "at this moment" (Drug Liking). Secondary objectives included VAS ratings for other subjective measures, and central nervous system (CNS) mu-opioid effects were assessed using pupillometry. Each subject received single oral doses of five treatments and matching placebo. RESULTS: Compared with 40 and 60 mg of oxycodone, the maximum mean Drug Liking score at 400 and 600 mg NKTR-181 was significantly lower, and the rate of onset and extent of Drug Liking for all NKTR-181 doses in the first two hours postdose were also significantly lower. Delayed attenuated Drug Liking and pupillary miosis response following administration of NKTR-181 vs oxycodone were consistent with slower NKTR-181 CNS entry kinetics and mu-opioid receptor binding. No adverse events were rated as severe, and somnolence and dizziness occurred more frequently when subjects received oxycodone. CONCLUSIONS: NKTR-181 at oral doses of 400 and 600 mg showed significantly fewer and less severe subjective effects accepted as representative of opioid abuse potential, such as lower peak Drug Liking in recreational opioid users, than 40 and 60 mg of oxycodone.

A randomized trial of budiodarone in paroxysmal atrial fibrillation.

OBJECTIVE: The aim of this study was to investigate the preliminary safety and efficacy of three doses of budiodarone in patients with paroxysmal atrial fibrillation. BACKGROUND: Budiodarone is a chemical analogue of amiodarone and shares its mixed ion channel electrophysiological properties. It has a shorter half-life than amiodarone. METHODS: Patients with paroxysmal atrial fibrillation and a previously implanted dual-chamber pacemaker capable of storing electrograms for at least 4 weeks were enrolled. Pacemaker memories were used to quantify atrial tachycardia/atrial fibrillation burden (AT/AFB). All antiarrhythmic drugs were stopped for greater than five half-lives and amiodarone greater than 3 months prior to enrollment. Following a 4-week baseline period to assess AT/AFB off antiarrhythmic drugs, patients with AT/AFB between 3% and 70% were blindly randomized to placebo, 200, 400, or 600 mg BID of budiodarone for 12 weeks followed by a 4-week washout period. Pacemakers were interrogated and safety assessed every 4 weeks. Pacemaker-derived electrograms were adjudicated blinded to treatment assignment. The primary study endpoint was percent change from baseline AT/AFB over 12 weeks of treatment compared to placebo. RESULTS: Of 72 randomized patients, 61 completed the study. The median reduction of AT/AFB for the 400 and 600 mg BID groups vs. placebo was 54% and 74% (p = 0.01 and 0.001), respectively. The budiodarone dose-response was statistically significant (p < 0.001). Number and duration of AT/AF episodes were reduced. CONCLUSIONS: In this preliminary study, budiodarone at both higher doses significantly reduced AT/AFB. The study is novel because dual-chamber pacemakers, previously placed for standard clinical indications, were successfully used to monitor AT/AFB.