Probuphine

Probuphine (generic: buprenorphine) is an investigational drug currently under FDA review for the treatment of opioid dependence (addiction to opioid drugs such as heroin and narcotics). Buprenorphine, the active ingredient in Probuphine, belongs to a group of drugs called opioid (narcotic) partial agonists. It is useful in treating opioid dependence by interacting with some of the same receptors in the brain that are triggered by the abused drug, producing effects that are similar to, but weaker than those of the abused drug, leading to fewer withdrawal symptoms and cravings.

Probuphine comes in the form of a small, solid implant that is placed by a healthcare provider under the skin, usually in the upper arm. The drug substance is released slowly and continuously into the body for 6 months from a single implant. The Probuphine implant is removed at the end of the treatment period.

Titan Pharmaceuticals, Inc. announced that on April 30, 2013, the U.S. Food and Drug Administration (FDA) issued a Complete Response Letter (CRL) to its New Drug Application (NDA) for Probuphine. The CRL states that the FDA will not approve the application at this time. The FDA has requested additional data supporting the efficacy of Probuphine, including:

• The ability of Probuphine to provide opioid blockade of relevant doses of agonists
• The effect of higher doses of Probuphine, ideally doses more closely approximating the blood plasma levels associated with sublingual doses of buprenorphine of 12 to 16 mg / day
• Human factors testing of the training associated with Probuphine’s insertion and removal

The CRL also included recommendations regarding product labeling and the implementation of the Risk Evaluation and Mitigation Strategy (REMS).