UPDATE 1-Raptor says prelim data on liver disease drug positive

* Says study positive on adolescent patients

* Patients with non-alcoholic steatohepatitis * Shares jump 46 pct to new year-high

Oct 12 (Reuters) - Raptor Pharmaceuticals Corp RPTPD.O said its experimental treatment for a progressive form of liver disease in adolescent patients met its key goal in a mid-stage trial, driving its shares up as much as 46 percent.

The study met its primary end point, which was a 50 percent drop in mean blood levels of alanine aminotransferase (ALT), a common biomarker for non-alcoholic steatohepatitis, the company said in a statement.

Additionally, over half of the study participants had achieved normalized ALT levels by the end of the treatment phase, Raptor said.

Shares of the company were up 27 percent at $4.25 in morning trade on Nasdaq. They touched a 52-week high of $4.90 earlier in the session on Monday. (Reporting by Shailesh Kuber in Bangalore; Editing by Gopakumar Warrier)