A Multicenter, Randomized, Placebo-Controlled Study to Evaluate the Efficacy and Safety of Long-Acting Injectable Formulation of Vanoxerine (Vanoxerine Consta 394.2 mg) for Cocaine Relapse Prevention

Abstract

Objective: To determine the efficacy and tolerability of a long-acting intramuscular formulation of Vanoxerine (Vanoxerine Consta 394.2 mg) for treatment of cocaine-dependent patients. Design, Setting, and Participants: A 12-week, A multicenter, randomized, placebo-controlled trial conducted between June 2009-July 2011, at 17 Hospital-based drug clinics, in the 15 countries. Participants were 18 years or older, had Diagnostic and Statistical Manual of Mental Disorders-5 cocaine use disorder. Of the 2800 patients who were assessed between March 10, 2009 to August 10, 2010, 2600 (93%) were eligible and willing to take part in the trial and were enrolled: 1300 were randomly assigned to receive injections of Long-acting depot formulations of Vanoxerine (Vanoxerine Consta 394.2 mg) given intramuscularly once in 12 weeks and 1300 to receive Placebo injections, given intramuscularly once in 12 weeks. Only 100 of 2800 patients (3.6%) did not meet the inclusion criteria. Main Outcomes and Measures: The primary endpoints (protocol) were: Confirmed Cocaine abstinence (percentage i.e. the number of patients who achieved complete abstinence during 12 weeks). Confirmed abstinence or “cocaine-free” was defined as a negative urine drug test for cocaines and no self-reported cocaine use. Secondary end points included a number of days in treatment, treatment retention and craving. The study also investigated, on 275 participants, degree and time course of Central Dopamine transporter receptor occupancy following single doses of long-acting intramuscular formulation of Vanoxerine (Vanoxerine Consta 394.2 mg) as well as the plasma concentration of Vanoxerine and 17-hydroxyl Vanoxerine. Safety was assessed by adverse event reporting. Results: Of 2600 participants, mean (SD) age was 28.5 (±5.5) years and 598 (23%) were women. 1300 individuals were randomized to receive injections of Long-acting depot formulations of Vanoxerine (Vanoxerine Consta 394.2 mg) and 1300 to receive injections of Placebo. 1417 participants (54.5.0%) completed the trial. Primary Endpoints: Confirmed Cocaine Abstinence: Complete abstinence was sustained by 72% (n = 936) of Vanoxerine patients (patients treated with Vanoxerine Consta 394.2 mg, long-acting depot formulations) compared with 37% (n = 481) of patients treated with Placebo, during weeks 5 - 12. The difference was significant as evaluated using a Chi-square test (χ2 = 672.34, P < 0.0001). Secondary Endpoint: Craving: A statistically and clinically significant reduction in cocaine craving was observed with Vanoxerine (Vanoxerine Consta 394.2 mg, long-acting depot formulations) vs. Placeboby week 4 (P = 0.0048), which persisted every week through 12 (P < 0.0001). Patients given Vanoxerine (Vanoxerine Consta 394.2 mg, long-acting depot formulations) had a 87% decrease in craving from baseline to 12th week. Patients given a Placebo had a 2% increase in craving from baseline to 12th week. Secondary Endpoint: Treatment Retention: Long-acting intramuscular formulation of Vanoxerine (Vanoxerine Consta 394.2 mg) helped significantly more patients complete 12 weeks treatment (n = 936, 72%) compared with Placebo (n = 481, 37%) (χ2 = 635.53, P < 0.0001). Patients on the long-acting intramuscular formulation of Vanoxerine (Vanoxerine Consta 394.2 mg) had longer treatment retention than patients on Placebo. Concentrations of Vanoxerine and 17-Hydroxyl Vanoxerinein Plasma: Analyses were made of 275 study samples. There was no statistically significant difference for plasma Vanoxerine concentrations between days 2 and 84 (p = 0.416). The plasma concentration of Vanoxerine were 70.4 and 94.3 ng/ml and concentrations of 17-hydroxyl Vanoxerine were 10.5 and 13.2 ng/ml, respectively. Plasma levels of Vanoxerine remained above 70 ng/ml for approximately 12 weeks after administration of Vanoxerine, long-acting depot formulations (Vanoxerine Consta 394.2 mg). PET Assessments: Very high central dopamine transporter receptor occupancy by Vanoxerine was detected 1 day after treatments, at which time point the occupancy was 100.0% after Vanoxerine injection (Vanoxerine Consta 394.2 mg). At days 7, 28, 56 and 84 post-Vanoxerine Consta 394.2 mg administration, occupancies were 95% to 79%. Vanoxerine Consta 394.2 mg injection (long-acting intramuscular formulation of Vanoxerine) led to very high occupancy of Central Dopamine transporter receptors in all brain areas examined; nucleus accumbens, caudate nucleus and putamen. Depending on the brain area Central Dopamine transporter receptor occupancy varied between 95.0% and 79% at days 7, 28, 56 and 84 after dosing. High Vanoxerine occupancy (77%) persisted at 12 weeks after the dosings. Adverse Reactions: Adverse events were similar in cocaine-dependent patients treated with the long-acting intramuscular formulation of Vanoxerine (Vanoxerine Consta 394.2 mg) vs. patients treated with Placebo. Conclusions and Relevance: Long-acting depot formulations of Vanoxerine (Vanoxerine Consta 394.2 mg) were more effective than Placebo injection in maintaining short-term abstinence from cocaine and should be considered as a treatment option for cocaine-dependent individuals.