A man sitting on a staircase with people walking past him

The man in the center is more depressed than Alkermes' investors are today. Image source: Getty Images.

Get the latest Alkermes stock news and facts.

What happened

Alkermes (NASDAQ:ALKS) is up 30% at 12:43 p.m. EDT after announcing positive phase 3 trial data for its antidepressant drug ALKS 5461.

So what

Alkermes tested ALKS 5461 in patients with major depressive disorder who haven't been helped by other drugs. At the higher dose, ALKS 5461 improved symptoms of depression -- based on two different scales used by doctors -- compared with placebo. The lower dose also helped patients, but the improvement wasn't statistically different from the data for the group that got the placebo.

In January, ALKS 5461 failed two earlier phase 3 trials. The company blamed the failures on the placebo effect. 

Given the unmet need, Alkermes plans to talk to the Food and Drug Administration about submitting a marketing application for ALKS 5461 based on this trial and previously released data.

Now what

We'll have to wait and see if the FDA is willing to approve ALKS 5461 based on the data Alkermes has on hand. If worst comes to worst, the FDA will want more data to approve the drug, but today's results should give investors some confidence that subsequent data will be positive.

Brian Orelli has no position in any stocks mentioned. The Motley Fool recommends Alkermes. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.