FDA delays approval of Prestwick drug

The approvable letter specifies conditions that the company must meet prior to obtaining approval to market Xenazine (tetrabenazine) in the US. In this letter, the FDA also indicated its intent to discuss the company’s new drug application (NDA) at an advisory committee meeting, the date for which has not yet been set.

“Prestwick is committed to making Xenazine available in the US as a treatment option for patients with chorea associated with Huntington’s disease. We plan to work closely with the FDA to satisfy the conditions specified in the approvable letter and to present the safety and effectiveness of Xenazine to the advisory committee,” said Dr Kathleen Clarence-Smith, CEO of Prestwick Pharmaceuticals.

Xenazine is a highly selective and reversible dopamine depletor that works by inhibiting vesicular monoamine transporter 2 (VMAT2). Xenazine is the first product for which an NDA has been filed in the US for treatment of chorea associated with Huntington’s disease (HD).

Chorea, a debilitating feature of a number of neurological diseases, is characterized by excessive, involuntary, and repetitive movements, which may involve the face, limbs, or the entire body. In HD, it is the result of overactivity of the neurotransmitter dopamine.

The FDA designated tetrabenazine an orphan product for Huntington’s disease as well as giving it fast track status. Xenazine is approved in eight markets outside of the US and is currently marketed by Prestwick Pharmaceuticals Canada as Nitoman.