Pharnext’s hopes of a quick approval for its Charcot-Marie-Tooth disease project PXT3003 have been dashed by the US FDA. The agency’s request for a second phase III study of the asset could have been foreseen after formulation issues halted the high-dose arm of the previous trial, Pleo-CMT; this was the only dose to show a significant benefit on the primary and secondary endpoints. Still, Pharnext’s stock was down as much as 42% today, below its price when the company reported the first phase III data last October. Pharnext has not given details of the new trial’s design, but there must be worries about whether the group can complete it: Pleo-CMT took three years to yield data, and Pharnext had just €32m ($35m) in cash at the end of March. PXT3003, a combination of baclofen, naltrexone and sorbitol, is in a long-term follow-up study set to yield data later this year. The company is also seeking a fast approval for PXT3003 in Europe, but it now looks likely that regulators there will also request another study. According to EvaluatePharma the only other prominent project in clinical development for Charcot-Marie-Tooth disease is Acceleron’s ACE-083, which is in phase II.