Long-acting buprenorphine implant effective for opioid dependence

Phase 3 study results presented at the American Society of Addiction Medicine annual conference indicated efficacy of Probuphine, a 6-month subdermal buprenorphine implant, for long-term maintenance treatment of opioid addiction.

“This was the first head-to-head comparison study of Probuphine and sublingual buprenorphine, demonstrating the efficacy of a long acting 6-month buprenorphine implant,” study researcher Richard N. Rosenthal, MD, of the Icahn School of Medicine at Mount Sinai, said in a press release. “The study results show that participants in the implant group sustained clinical stability over the course of 6 months. The implant group was also more likely to remain free from illicit opioids at 85.7% compared to 71.9% of those maintained on sublingual buprenorphine. If approved, Probuphine could help expand access to medication to treat opioid use disorders, providing people with a new option.”

To assess efficacy and safety of Probuphine (buprenorphine, Titan Pharmaceuticals Inc.), researchers conducted a double-blind, double-dummy, multisite study among 177 adults with opioid dependence who were clinically stabilized for at least 3 months on 8 mg or more of sublingual buprenorphine. Participants were randomly assigned to receive daily sublingual buprenorphine tablets at their previous maintenance dose and four placebo implants or daily sublingual buprenorphine tablets plus four long-acting buprenorphine implants. The intent-to-treat population included 173 participants, of which 84 received long-acting buprenorphine implants. Following implantation, participants provided urine samples at six scheduled monthly visits and four randomly assigned visits.

Analysis indicated a responder rate of 87.6% in the sublingual buprenorphine group and 96.4% in the buprenorphine implants group.

Further, results indicated statistically significant superiority for buprenorphine implants vs. sublingual buprenorphine (P = .034).

Illicit opioid use occurred in 28.1% of the sublingual buprenorphine group and 14.3% of the buprenorphine implants group.

One participant in the buprenorphine implants group discontinued due to muscle spasms. There were no discontinuations in the sublingual buprenorphine group.

Severe adverse events occurred in 10.1% of the sublingual buprenorphine and 3.4% of the buprenorphine implants group (P > 0.05).

Treatment-emergent adverse events of any severity occurred in 6.7% of the sublingual buprenorphine group and 16.1% of the buprenorphine implants group (P > 0.05).

“Like any chronic disease, the ability to personalize treatment is key to long-term success and quality of life for opioid dependent individuals,” Frank J. Vocci, PhD, president and senior research scientist at Friends Research Institute. “The data presented today on Probuphine provides hope for a new option that could address critical issues like medication compliance and the risks of oral buprenorphine.”

Probuphine is currently under final review by the FDA following a 12 to 5 vote by the FDA’s Psychopharmacologic Drugs Advisory Committee in favor of approving the treatment in January 2015.