Stock for Carlsbad-based Isis Pharmaceuticals Inc. has risen 13 percent on news that midstage trials for its experimental heart drug have been successful.

Shares closed Sept. 4 at $29.13 — up $3.30 since the Aug. 31 announcement that Isis’ (Nasdaq: ISIS) compound, called APOIII, reduced the number of triglycerides found in the bloodstream of more than three-quarters of the patients tested.

This isn’t the first time that news on APOCIII sent Isis stock soaring. In June, stock rose about 30 percent after the drug reportedly reduced blood fat levels in diabetics. Isis is a $3.36 billion market cap company that develops RNA-based therapies to deactivate disease-causing genes.

— Meghana Keshavan