BETHESDA, Md. (
) -- An FDA advisory panel will spend Thursday reviewing a long-acting treatment for opioid addiction from
The panel is expected to be contentious because FDA's own reviewers expressed doubts about the ability of Titan's drug, known as Probuphine, to adequately curb addiction. The FDA's concerns, made public in a review of Probuphine released Tuesday, caused Titan shares to fall 41% to $1.19. The stock rebounded slightly Wednesday, closing at TK.
Probuphine is a small plastic rod embedded with buprenorphine that is implanted under the skin of the upper arm. Unlike oral forms of buprenorphine that must be taken daily, Probuphine is designed to release buprenorphine continuously for six months.
Titan conducted clinical studies demonstrating that opioid addicts implanted with Probuphine were less likely to relapse than patients treated with placebo. The FDA, in its review, said Probuphine's dose may be too low to produce clinically meaningful results. A majority of Probuphine patients in the study required additional oral buprenorphine and only 8% of patients reported opioid-negative urine tests for at least 80% of tests.
"While the placebo group had even more discouraging results, supporting the conclusion that Probuphine does have an effect on drug use, overall, the response was not what one might hope for given that the product ensures compliance with the medication for six months," the FDA review stated.
FDA also raised concerns about the complications arising from the surgical insertion and removal of the Probuphine implant.
Sales of oral forms of buprenorphine, mostly quick-dissolving tablets and film, totaled more than $1 billion last year.
-- Reported by Adam Feuerstein in Boston.