United Therapeutics (UTHR) - Get Report rose 5% late Monday after the biotech guided toward a better-than-expected third quarter and said it would buy back 4 million shares.

United said it would raise $210 million through the sale of five-year convertible notes in a private placement to fund the buyback. The company also said 130 patients have enrolled in a 200-patient trial of inhaled treprostinil.

The Silver Spring, Md., company said it expects its third quarter to be flat with second-quarter results. The company made 73 cents a share on an adjusted basis in that quarter on revenue of $40 million.

Analysts surveyed by Thomson Financial were looking for a 54-cent profit for the quarter ended Sept. 30 on sales of $38 million.

The company said 130 patients have been enrolled in United Therapeutics' Triumph-1 trial, a 200-patient 12-week placebo-controlled trial of inhaled treprostinil in pulmonary arterial hypertension. United Therapeutics believes that the improvement in enrollment pace makes it unlikely that the company will perform an interim assessment after 150 evaluable patients have completed the study. As a result, the Triumph-1 trial is expected to conclude when 200 evaluable patients have completed the study, which is expected to occur following the enrollment of approximately 220 patients overall.

In addition, enrollment has commenced in United Therapeutics' Freedom-C (combination therapy) trial, a 16-week placebo-controlled trial of UT-15C sustained-release oral treprostinil in pulmonary arterial hypertension. The Freedom trials -- Freedom-C and Freedom-M, a 12-week frontline monotherapy trial -- are expected to enroll 450 patients at 50 centers worldwide, subject to interim assessments.

Shares rose $3.16 to $60.17.