** Shares of Praxis Precision Medicines PRAX.O fall ~10% to $301.95 premarket

** Co said late on Monday its experimental epilepsy drug failed to reduce frequency of seizures in a month, missing the main goal of a mid- to late-stage study

** The setback prompted PRAX to pause enrollment in another ongoing study while it reassesses the program

** The drug, vormatrigine, was being tested in adults with focal onset seizures, a neurological disorder characterized by abnormal electrical activity in a specific area of the brain

** This was a "result we did not anticipate," BTIG analysts said, adding that the vormatrigine program "is not without a recoverable path"

** BTIG cuts PT on PRAX to $810 from $843, projecting a 50% chance for the program to succeed, down from 70% previously

** Up to last close, stock has gained nearly 14% YTD