Neuralstem Inc. CUR, shares plummeted 61% in premarket trade Tuesday on news of a mid-stage clinical trial miss for its major depressive disorder drug. The drug, NSI-189, did not meet its primary endpoint of a statistically significant reduction in depression symptoms. The company said that the drug did meet a secondary efficacy endpoint of statistical significance on the patient-rated Symptoms of Depression Questionnaire. That secondary endpoint was one of two that the company said it has analyzed so far. "We are encouraged by its emerging clinical profile, and continuing the clinical evaluation of NSI-189 to pursue its full potential is warranted," Dr. Maurizio Fava, the trial's principal investigator, said. Neuralstem shares have surged 12.3% over the last three months to $5.58, compared with a 3.4% rise in the S&P 500 SPX, -1.11% .