Drug company United Therapeutics saw its shares fell 12 percent on Wednesday after its fourth-quarter revenue fell short of Wall Street expectations.

Revenues for the fourth quarter increased by 1 percent to $409 million, compared to $404.9 million in the same period in 2015. Analysts expected the company to report revenue of $415.5 million.

“The quarterly trends for the fourth quarter were down from the third quarter, but this is a typical quarterly choppiness that we see with our sales,” said Chief Executive Officer Martine Rothblatt on the earnings conference call.

United Therapeutics stock closed down 12.47 percent Wednesday, from $167.92 to $146.98.

Once adjusted for stock option expense and non-recurring costs, earnings were $4.12 per share, beating analyst expectations. Of 10 analysts, the average earnings per share expectation was $3.61.

The Silver Spring-based company reported net income of $110.3 million, or $2.43 per share, compared to $104.6 million, or $2.10 per share, in the same quarter of 2015.

For the year, the company reported a profit of $713.7 million, or $15.25 per share.

The hypertension pill Adcirca saw $21.2 million in additional sales for the quarter, but sales of the hypertension drug Tyvaso fell by $25.6 million, offsetting fourth-quarter growth.

Total revenues for 2016 increased by 7.7 percent to $1.6 billion, up from $1.47 billion last year. Revenue growth for the year was driven by a $93.4 million increase in sales of Adcirca.

The 8-K filing can be found here.