Gemphire Therapeutics Inc.'s cholesterol drug, gemcabene, met its primary endpoint in a phase 2b study but failed to match results observed in previous trials.

Under the Royal-1 trial, gemcabene was seen to significantly decrease low-density lipoprotein cholesterol, or LDL-C, in hypercholesterolemic patients: 17.2% versus 5.5% for placebo, but still lower than what was observed previously.

The trial enrolled 56 females and 49 males with a mean age of 61.

Gemphire Therapeutics shares were down nearly 47% to $9.93 at market close on Aug. 7.