Biohaven falls as US FDA rejects rare nerve disease drug application

Shares of drugmaker Biohaven BHVN.N fall 45% to $7.72 premarket

Co says U.S. FDA has rejected its application to approve troriluzole, a drug for spinocerebellar ataxia (SCA), a rare inherited brain disorder that causes loss of movement and has no approved treatments

The FDA in its so-called complete response letter (CRL) said it was concerned about the design and reliability of co's main study for troriluzole, citing bias and flaws in real-world data used instead of standard trial methods

BHVN says troriluzole slowed disease progression and reduced fall risk in trials

BHVN to meet U.S. FDA to discuss future path for approval, co says

Up to last close, stock down ~63% YTD