What happened

Intra-Cellular Therapies (NASDAQ:ITCI) stock outperformed a booming market last month by jumping 253% compared to a 3% spike in the S&P 500, according to data provided by S&P Global Market Intelligence.

The rally closed an impressive year for shareholders in the biotech stock, which rose 200% for the year to far outpace the market's 29% gain.

Two clinical researchers at work over a microscope

Image source: Getty Images.

So what

December's rally was sparked by encouraging news about one of its most promising drugs, Caplyta. The schizophrenia treatment was approved for sale in the U.S. by the Food and Drug Administration, the company said on Dec. 23. Caplyta was found to significantly improve symptoms of the disease, which affects roughly 2.4 million adults in the U.S. alone. 

Now what

When it goes on sale in early 2020, Caplyta will be Intra-Cellular Therapies' first commercialized property and will need to attract significant demand to help justify the stock's $1.7 billion market capitalization. Yet shareholders are hoping December's FDA approval is just the first of many to come in the field of neurological diseases, including treatments for Alzheimer's, depression, and bipolar disorder.