The first study was a phase IIa study of TA-CD conducted by Dr Margaret Haney, associate professor of Clinical Neuroscience at Columbia University. The study looked at the impact of vaccinating chronic cocaine-dependent volunteers who were not actively seeking to reduce or stop their cocaine use.
Results demonstrated that volunteers who successfully developed good levels of anti-cocaine antibodies in their blood experienced an decrease of the “high” normally expected from cocaine use. This response also resulted in a substantial reduction in the amount of cocaine the volunteers reported using. The study was well controlled and provides encouraging evidence for the potential utility of this therapeutic approach.
The second study was a double-blinded placebo controlled phase IIb study in 114 patients, conducted by Professor Thomas Kosten, chief, Psychiatry Service at Yale University School of Medicine, which looked at cocaine users who were also on methadone maintenance therapy for treatment of heroin addiction.
The primary end-point was an improvement in abstinence from cocaine for three consecutive weeks; this challenging end-point in patients with an average of thirteen years of cocaine abuse was not achieved in part due to a higher than expected placebo effect in the study.
Nevertheless, some significant indications of efficacy were demonstrated in the study including twice as many patients in the treatment group achieving a 50% or greater increase in cocaine-free days as measured by urine analysis.
“We are encouraged by the results from both studies of TA-CD, which support the mechanistic and pharmacological underpinnings of this novel immunotherapy vaccine for the treatment of addiction,” commented Dr Kosten. “While more detailed analyses of the clinical data from these two studies is ongoing, the results are already providing valuable insight for TA-CD's future study design and regulatory options.”