** Drug developer Praxis Precision Medicines' PRAX.O shares surge 90.2% to $109.09 premarket
** Co says its experimental movement disorder drug ulixacaltamide met the main goals of two late-stage studies for essential tremor
** Essential tremor causes involuntary shaking, often in hands, disrupting daily tasks
** Patients on drug showed improved functioning and maintained the effect over time - PRAX
** Co says no drug-related serious side effects; most common were dizziness, brain fog
** Up to last close, stock was down ~25% YTD
(Reporting by Sahil Pandey in Bengaluru)
((Sahil.pandey@thomsonreuters.com))