** Shares of biotech firm Praxis Precision Medicine PRAX.O down ~12% at $293.81 after the bell

** Co says its experimental epilepsy drug did not meet the main goal of reducing monthly seizure frequency in a mid-to-late-stage study

** Co to pause enrollment in another ongoing study to reassess the vormatrigine program and determine potential modifications

** The treatment met a secondary measure where more patients saw at least a 50% reduction in seizures, Praxis says

** Adds the trial was studying the safety and efficacy of vormatrigine in adults with focal onset seizures (FOS) who are concurrently taking at least one but no more than three acceptable anti-seizure medications

** Co notes seizure reduction was more pronounced during the second half of the study on higher 30 mg dose

** Up to last close, stock rose nearly 14% YTD