What happened?

Shares of Supernus Pharmaceuticals (SUPN -0.73%) are up by 16.7% as of 2:18 p.m. EST on Wednesday after rising by as much as 22.4% earlier today. Investors are bidding up shares of the biopharmaceutical company following its release of positive results from a phase 3 clinical trial for one of its leading pipeline candidates.

So what

A phase 3 trial investigating the efficacy of Supernus Pharmaceuticals' SPN-812 on adults with attention deficit hyperactivity disorder (ADHD) showed that the medicine was able to improve the symptoms of the condition when compared to the placebo, which was the study's primary endpoint. The drugmaker also reported that SPN-812 had a favorable safety profile throughout the study. Note that this medicine has already been reviewed by the U.S. Food and Drug Administration (FDA) for the treatment of ADHD in patients between the ages of 6 and 17.

Hand drawing upward pointing graph.

Image source: Getty Images.

Back in November, the health regulatory agency issued a Complete Response Letter (CRL) to Supernus Pharmaceuticals indicating that it could not approve the drug yet due to concerns unrelated to SPN-812's safety and efficacy. The company will meet with the FDA in January to discuss the next steps for the potential approval of SPN-812 for patients aged 6 through 17, and if all goes well, Supernus Pharmaceuticals will submit another application for the drug, this time for adult ADHD patients, in the second half of 2021.

Now what

Supernus Pharmaceuticals is an intriguing play for those looking for under-the-radar biotech stocks to invest in. In addition to SPN-812, which could win regulatory approval and go on to tap into a "significant market opportunity" in the ADHD market, the company is also developing other medicines for central nervous system disorders, including epilepsy, depression, and Parkison's disease. Of course, there is always the possibility of clinical trial failure or regulatory setbacks, which is why interested investors should consider the risks first, and for those who decide to initiate a position, it is probably best to start small.