** Shares of drug developer Pasithea Therapeutics rise 64.3% to $6.31 premarket

** KTTA says its experimental cancer drug, PAS-004, was safe and well tolerated in an early-stage study

** Says one heavily pre-treated patient with stage three colon cancer showed prolonged stable disease

** Co is testing the drug in certain cancer patients whose tumor has an RAF mutation

** Says no treatment-related adverse events were observed and no drug-related dose interruptions or discontinuations

** Co expects to provide additional trial updates on a periodic basis as the trial progresses

** Up to last close, stock down 48% YTD

(Reporting by Sneha S K)

((Sneha.SK@thomsonreuters.com;))