June 11 (Reuters) - Sage Therapeutics said on Tuesday its experimental drug was found to be safe and showed some effect in patients with a rare, genetic neurological condition called Huntington's disease in a part of a mid-stage study.

The company, however, said the study in Huntington's disease patients was not designed to show a statistically significant difference between the drug dalzanemdor and placebo.

Shares of the company, which soared 80% initially, erased those gains and were down 1.6% in volatile premarket trading.

The news follows a mid-stage trial failure for the same drug, in April when it was tested in patients with Parkinson's disease. (Reporting by Sriparna Roy in Bengaluru; Editing by Shailesh Kuber)