Things are not looking good for Jazz’ date rape drug-based fibromyalgia candidate after a panel of US Food and Drug Administration advisors largely voted against recommending its approval.

The group’s shares plummeted nearly 30% after an FDA Joint Advisory Committee voted 20-2 that the benefit/risk balance did not support the approval of JZP-6 (gamma hydroxybutyrate; GHB), the proposed brand name for which is Rekinla, as a treatment for fibromyalgia.

While documents released earlier this week ahead of the review showed the FDA believes the drug is indeed effective in treating the pain condition, concerns over the potential for abuse and accidental overdose continue to overshadow its therapeutic benefit.

GHB - a nervous system depressant - is already sold by Jazz as a treatment for narcolepsy under the brand name Xyrem, but because of the potential for abuse the drug’s sale is highly restricted and only available to registered patients and doctors via a central pharmacy, and a similar pathway has also been proposed for Rekinla.

The group said it is disappointed with the panel’s recommendation, but said its plans to work closely with FDA on the continuing review of our new drug application for the drug. “We will carefully consider the input of the committee as we seek to address the needs of fibromyalgia patients for new treatment options in a safe and responsible way,” said Bruce Cozadd, chairman and Jazz’ chief executive.

The company is reportedly expecting the FDA to complete its review by October 11.