United Therapeutics Corp. jumped 18 percent in New York trading, after gaining U.S. marketing approval for the oral version of its treatment for high blood pressure in the arteries that supply the lungs.

The drugmaker climbed to $104 at 8:46 a.m., on the first trading day after announcing Dec. 20 that the Food and Drug Administration had cleared sales of orenitram for the treatment of pulmonary arterial hypertension to improve exercise capacity in some patients.

The approval was Silver Spring, Maryland-based United Therapeutics’ fifth for a pulmonary hypertension treatment, Roger Jeffs, the company’s president and chief operating officer, said in the statement. The FDA had rejected the oral version of the therapy twice before, in March and in October 2012.

The decision will further “our mission of providing a wider choice of PAH therapies for physicians and patients,” the CEO said in the statement. “We are grateful for the FDA’s thorough review and will continue to build clinical support for the use of orenitram.”

The pill’s active ingredient, treprostinil, is the same as in the company’s approved injection and inhalation solution for PAH, a life-threatening disorder, United Therapeutics said.

The shares had gained 64 percent for the year through last week.