“Titan Pharmaceuticals’ (now Braeburn Pharmaceuticals) Probuphine was rejected by the FDA in 2013 because patients who had the implant still needed to take “rescue” doses of buprenorphine.
To mitigate that problem, the company has narrowed the indication to patients who are already stabilized on 8 mg sublingual buprenorphine daily or less, after completing an additional trial showing non-inferiority in this population.
But FDA reviewers writing ahead of the Psychopharmacologic Drugs Advisory Committee (PDAC) meeting next Tuesday have highlighted problems with that new study — particularly, that the responder rate “depends on a number of assumptions about missing data and also assumes that use of supplemental buprenorphine is not an indicator of inadequacy of treatment.”
“When analyzed under different assumptions, the response rates are lower than reported by the applicant, and also differ from the expected response rate used to calculate the non-inferiority margin,” the reviewers wrote. “Therefore, under some sets of assumptions, one might question whether enough of the effect size has been maintained to conclude efficacy of Probuphine.”
See related article: A Food and Drug Administration committee voted today in favor of approval for an implant designed to help people beat opioid addictions available at: http://www.cbsnews.com/news/fda-panel-favors-approval-of-implant-to-treat-opioid-addiction/
Source: MedPageToday.com – January 8, 2016