US-based pharmaceutical company Indivior has reported positive topline results from its pivotal Phase III clinical trial of RBP-6000 for opioid use disorder.
RBP-6000 is an investigational buprenorphine sustained-release formulation based on the ATRIGEL delivery system, which consists of a polymeric solution of a biodegradable, poly(DL-lactide-co-glycolide) co-polymer dissolved in N-methyl pyrrolidone (NMP), a water-miscible biocompatible solvent.
After being subcutaneously injected, NMP releases the polymer matrix and the polymer precipitates, which then traps the drug inside and creates an amorphous solid depot in situ.
The depot releases buprenorphine over a one-month period by diffusion as the polymer biodegrades.
The multicentre, randomised, double-blind, placebo-controlled Phase III clinical trial involved 489 patients with moderate or severe opioid use disorder with no prior disease-related treatment history.
The patients were initially subjected to SUBOXONE (buprenorphine / naloxone) sublingual film for three days, which advised on prevention of withdrawal from opiates and to ensure lack of allergy to buprenorphine.
After exhibiting no significant opioid craving or withdrawal, the patients were administered with RBP-6000 or placebo.
The study was primarily focused on determining the efficacy of RBP-6000 in two dosing regimens to combat opioid use disorder.
The secondary endpoint of the study was to achieve a treatment success with RBP-6000.
Results suggested that the study achieved its both its primary and secondary endpoints.
RBP-6000 was also well tolerated during the study.
Indivior chief scientific officer Christian Heidbreder said: "The treatment of opioid use disorder aims to reduce opioid drug misuse by decreasing cravings and addressing withdrawal symptoms.
“Treatment involves pharmacological and behavioral therapy, as well as psychosocial support to eventually end illicit drug-taking behaviour.
“Opioid use disorder is an underserved disease and we are pleased to add preliminary clinical evidence that supports the efficacy and safety of RBP-6000 in the treatment of this potentially fatal, chronic disease.
"With this compelling Phase 3 data in hand, we are on track to complete the data analysis of this Phase 3 trial, as well as the open-label, long-term assessment of the safety and tolerability of RBP-6000 by Q1 2017 in line with previous guidance."
The study coincides with the US government’s increased efforts to combat opioid abuse, addiction and overdose.
Image: Poppy pod used to develop opium. Photo: courtesy of US gov't site.