United Therapeutics (NSDQ:UTHR) said today that its board of directors approved the repurchase of up to $250 million of the biotech’s common stock.

The share repurchase program is effective immediately and United said it will stay open until the end of 2017. The company can make purchases in the open market, accelerated share repurchases or in privately negotiated transactions.

“We are pleased to continue our track record of returning value to our shareholders via stock repurchases,” chairman & CEO Martine Rothblatt said in prepared remarks. “When this new $250.0 million repurchase program is completed, we will have returned over $2.0 billion to our shareholders over a six-year period, repurchasing more than 35% of our outstanding shares during that time.”

Also this week, United shares fell after the company missed earnings and revenue expectations on The Street with its 1st quarter results.

The Silver Spring, Md.-based company posted profits of $178.6 million, or $3.89 per share, on sales of $370.5 million for the 3 months ended March 31, for bottom-line loss of -24% on sales growth of 0.4% compared with the same period last year.

In early April, the Patent Trial and Appeal Board of the U.S. Patent and Trademark Office ruled that the claims of a United patent that covers Remodulin are unpatenable due to obviousness. SteadyMed (NSDQ:STDY) challenged the patent in October last year.

The patent, No. 8,497,393, relates to the process to purify prostacyclin derivatives, including treprostinil, which is the active ingredient in United’s Remodulin and SteadyMed’s Trevyent.