Anti-addiction drug delivery implant outperforms placebo
Buprenorphine is currently administered sublingually but there are concerns about compliance, diversion and the potential for recreational use and abuse. To address these concerns Titan Pharmaceuticals is developing an implantable device that is currently in Phase III.
Results from a company-funded, 24-week Phase III trial of 163 patients have been published in the Journal of the American Medical Association (JAMA). Patients with the buprenorphine implant had fewer urine samples positive for illicit opioids during weeks one to 16.
The mean percentage of urine samples testing negative for illicit opioids from weeks one to 16 was 40.4 per cent in patients receiving buprenorphine via implant, compared to 28.3 per cent in placebo patients. Median figures were 40.7 per cent for the implant and 20.8 per cent for placebo.
Furthermore, patients with the implant were more likely to complete the trial, had fewer withdrawal symptoms and experienced a greater change in clinician global ratings of severity of opioid dependence.
Minor implant site reactions, the most common adverse event, were experienced by 56.5 per cent of patients with the buprenorphine implant and 52.7 per cent receiving the placebo.
Probuphine
The Phase III trial investigated the use of Probuphine, a sub-dermal implant based on ProNeura technology developed by Titan. Buprenorphine HCL is embedded in a polymer matrix and released over a period of up to six months.
Released buprenorphine binds to opioid receptors in the brain, potentially blocking other opioids from attaching. Blocking other opioids could reduce the potential for addictive behaviour.
“By providing a sustained blood level of active medication, Probuphine helps diminish the daily fluctuation of the medication effects – and potentially side effects – and reduces the total exposure of buprenorphine over time", said Walter Ling, lead author of the research paper.
Enrolment in another Phase III trial is now complete and Titan expects it to generate results in the second quarter of 2011. Data from this study will be used by Titan as it tries to obtain marketing approval in the US and Europe.
