Data from a previously completed and announced Phase 3 randomized, placebo-controlled clinical trial of Probuphine were unveiled by Titan Pharmaceuticals, Inc. The results were published in the Journal of the American Medical Association (JAMA).
The article highlights data from the 163-patient trial, which showed that patients receiving Titan's Probuphine implant had significantly less illicit opioid use, experienced fewer symptoms of withdrawal and craving, stayed in treatment longer and had greater overall improvement when compared to placebo patients over the course of the 24-week study.
Probuphine is an innovative, subcutaneous implant formulation designed using Titan's proprietary ProNeura™ technology to deliver a steady, round-the-clock low dose of the marketed drug buprenorphine over six months following a single treatment.
"The introduction of buprenorphine into clinical practice is arguably the most significant improvement in the treatment of opioid addiction in the last decade; however, physicians excited with the clinical success of buprenorphine are also rightfully concerned about medication adherence and diversion - and potential for abuse - of the sublingual formulations of buprenorphine," said Walter Ling, M.D., Professor of Psychiatry and Director, Integrated Substance Abuse Programs at the David Geffen School of Medicine at UCLA and the paper's lead author. "Probuphine does away with these concerns by eliminating the need for take home doses. Additionally, 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."
The publication, "Buprenorphine Implants for Opioid Dependence: A Randomized Controlled Trial" will appear in the October 13, 2010 issue of JAMA and details key trial results:
- Patients receiving Probuphine had a mean percentage of urine samples that tested negative for illicit opioids across the full 24 weeks of 36.6 percent; those in the placebo group had a mean of 22.4 percent (p=0.01)
- Nearly 66 percent of patients receiving Probuphine completed the study vs. the 31 percent who received placebo implants (p<0.001)
- Probuphine patients experienced fewer clinician-rated (p<0.001) and patient-rated (p=0.004) withdrawal symptoms
- Probuphine patients reported lower ratings of craving (p<0.001)
- Probuphine patients had a greater change on clinician global ratings of severity of opioid dependence (p<0.001)
- Probuphine patients demonstrated a greater change on the clinician global ratings of improvement (p<0.001)
- Minor implant site reactions were the most common adverse events and were consistent across the Probuphine and placebo groups
Titan is currently conducting a confirmatory Phase 3 clinical trial of Probuphine for the treatment of opioid addiction. Patient enrollment in that trial is now complete and results are expected in the second quarter of 2011, approximately three months ahead of the original schedule. This study is part of Titan's registration-directed program intended to obtain marketing approval of Probuphine for the treatment of opioid addiction in the U.S. and Europe.
"We believe that Probuphine represents a significant step forward in the safe and effective treatment of opioid addiction," said Dr. Katherine L. Beebe, Senior Vice President, Clinical Development and Medical Affairs and a co-author of the publication. "Probuphine was designed as an innovative implant formulation so that it could reduce the risk of diversion and abuse. With only one treatment, Probuphine provides a round-the-clock, effective low dose of buprenorphine over six months, which should significantly improve compliance. These improvements could change the way opioid addiction is treated and dramatically impact patients' lives."
The World Health Organization estimates that 2.8 million individuals in the U.S. and Europe are addicted to illicit opiates such as heroin, and more than 2.0 million individuals in the U.S. alone are addicted to prescription opioid medications. It is estimated that about 20 percent of this population are currently receiving pharmacological treatment.