US biotechnology company, Pozen, is to drop its migraine therapy MT 100 (metoclopramide plus naproxen) after a US Food and Drug Administration advisory panel declined to recommend its approval on concerns about the development of tardive dyskinesia – a severe movement disorder. However, all is not lost for the company as it plans to file for approval in the near future of a second-generation migraine drug known as Trexima (sumatriptan plus naproxen), which is licensed to GlaxoSmithKline for the US market [[19/05/04g]].

Committee Chair, Karl Kiebutz, commented: “The amount of benefit perceived or demonstrated so far…is not sufficient given the perceived risk.” In the trials overall, 4%-6% more patients treated with MT 100 had a sustained pain response versus those given naproxen alone. This difference was not of statistical significance, but amongst a subgroup of patients with no nausea at the outset, a significant benefit to MT 100 was observed – but was not extended to the two-hour pain response measure. Because of this finding, panel members said the risk of exposing patients to the combination therapy was too great. The FDA “must ask for extreme rigour with this particular drug,” concluded panel consultant, Michael Welch.

The metoclopramide portion of MT 100 has been linked to an unquantified risk of tardive dyskinesia, however Pozen says Trexima is not associated with this condition. “Trexima has already demonstrated greater efficacy without the metoclopramide risk associated with MT 100,” said John Plachetka, the company’s chairman, president and chief executive.

MT 100 has been non-approvable in the USA since June 2004.