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Vaccine for cocaine dependence: a randomized double-blind placebo-controlled efficacy trial

Kosten, Thomas R; Domingo, Coreen B; Shorter, Daryl; Orson, Frank; Green, Charles; Somoza, Eugene; Sekerka, Rachelle; Levin, Frances R; Mariani, John J; Stitzer, Maxine; Tompkins, D Andrew; Rotrosen, John; Thakkar, Vatsal; Smoak, Benjamin; Kampman, Kyle
AIMS: We evaluated the immunogenicity, efficacy, and safety of succinylnorcocaine conjugated to cholera toxin B protein as a vaccine for cocaine dependence. METHODS: This 6-site, 24 week Phase III randomized double-blind placebo-controlled trial assessed efficacy during weeks 8 to 16. We measured urine cocaine metabolites thrice weekly as the main outcome. RESULTS: The 300 subjects (76% male, 72% African-American, mean age 46 years) had smoked cocaine on average for 13 days monthly at baseline. We hypothesized that retention might be better and positive urines lower for subjects with anti-cocaine IgG levels of >/=42 mug/mL (high IgG), which was attained by 67% of the 130 vaccine subjects receiving five vaccinations. Almost 3-times fewer high than low IgG subjects dropped out (7% vs 20%). Although for the full 16 weeks cocaine positive urine rates showed no significant difference between the three groups (placebo, high, low IgG), after week 8, more vaccinated than placebo subjects attained abstinence for at least two weeks of the trial (24% vs 18%), and the high IgG group had the most cocaine-free urines for the last 2 weeks of treatment (OR=3.02), but neither were significant. Injection site reactions of induration and tenderness differed between placebo and active vaccine, and the 29 serious adverse events did not lead to treatment related withdrawals, or deaths. CONCLUSIONS: The vaccine was safe, but it only partially replicated the efficacy found in the previous study based on retention and attaining abstinence.
PMCID:4073297
PMID: 24793366
ISSN: 0376-8716
CID: 1450282

Valproate treatment and cocaine cue reactivity in cocaine dependent individuals

Reid, Malcolm S; Thakkar, Vatsal
Based on prior clinical trials indicating that gamma-aminobutyric acid (GABA)-based anticonvulsant medications reduce drug craving in cocaine dependent study participants, we tested the effects of valproate treatment on cue-induced cocaine craving. Crack cocaine dependent individuals (N=20) were tested in a randomized, placebo-controlled, within-subjects, crossover study design. Valproate treatment was titrated up to 1500 mg/day by Day 6 of treatment, cue testing was completed on Day 8 of treatment, and all study participants underwent a washout period of 5 days between active and placebo medication treatment periods. Testing included both cocaine and neutral cue exposure sessions, presented in a random and counterbalanced order. Main effects of cue exposure were found for subjective ratings of 'desire to use cocaine now', the cocaine craving index, cocaine-like high, and cocaine withdrawal. Treatment interaction effects were found with 'desire to use cocaine now', which underwent a greater increase following cocaine cue exposure in the valproate condition. Main effects of medication treatment were found, in which lower blood pressure and heart rate, and higher plasma cortisol levels, were associated with valproate treatment. Valproate treatment was also associated, at a trend level, with higher pre-test cocaine craving levels. The results demonstrate that cocaine cue reactivity is a robust phenomena across two assessment sessions, but fail to support the use of valproate as a means of reducing spontaneous and cue-induced cocaine craving. The use of valproate as a treatment for cocaine dependence is not supported
PMCID:2712872
PMID: 19375250
ISSN: 1879-0046
CID: 100423