Remodulin (treprostinil) is therapy that United Therapeutics developed to treat symptoms of pulmonary arterial hypertension, or PAH.

The U.S. Food and Drug Administration approved Remodulin in May 2002. It is administered as a continuous infusion or as an injection under the skin or into a vein.

How Remodulin works

PAH is a progressive condition characterized by the narrowing of pulmonary arteries, or blood vessels in the lungs. The narrowing restricts blood flow, increasing the pressure in the lungs and making it difficult to transport oxygen to the rest of the body.

The active component of Remodulin, treprostinil, is a man-made form of the hormone prostacyclin.

Prostacyclin, which widens blood vessels, is produced by cells in the walls of blood vessels. When it binds to receptors on cells lining pulmonary artery walls, it triggers signaling pathways that cause the blood vessels to relax and widen. Prostacyclin also prevents blood cells called platelets from clumping and blocking arteries.

By mimicking these two mechanisms, Remodulin is designed to help blood flow through the lungs more efficiently. This should increase oxygen availability to the rest of the body, making it easier for a patient to be active.

Remodulin in clinical trials

The FDA based its approval of Remodulin on the results of a 12-week clinical trial of 470 patients worldwide. The findings, published in the American Journal of Respiratory and Critical Care Medicine, showed that Remodulin improved PAH symptoms, compared with a placebo.

One measure of its effectiveness was its ability to improve patients’ exercise ability. The test  was how far a patient could walk in six minutes. Another effectiveness measure was whether Remodulin could reduce patients’ shortness of breath, assessed by the Borg dyspnea score. The therapy improved patients’ performance on both measures after 12 weeks, compared with the placebo group.

The FDA also weighed the results of a clinical trial of Remodulin’s long-term safety and effectiveness. The study followed 860 patients for up to four years. The results were published in The European Respiratory Journal.

Another trial was an eight-week, placebo-controlled evaluation (NCT00058929) of whether shifting patients from another prostacyclin therapy, Flolan, to Remodulin was safe and effective.

The results, published in the journal Chest, showed that Remodulin helped prevent functional deterioration in 93 percent of patients who had stopped taking Flolan, compared with only 12.5 percent taking a placebo.

United Therapeutics is also investigating Remodulin as a potential treatment for other conditions. An example is a Phase 2 clinical trial (NCT02261883) that is evaluating its effectiveness as an add-on treatment to standard therapies for babies with persistent pulmonary hypertension of the newborn. Researchers are recruiting up to 70 participants at multiple U.S sites.

Other information

Common side effects of Remodulin include reactions or pain at the injection site, headache, diarrhea, nausea, jaw pain, and swelling.

Remodulin was the first formulation of treprostinil to be approved as a PAH therapy. United Therapeutics also produces two other approved formulations. One, marketed under the brand name Orenitram, is extended-release oral tablets. The other, marketed as Tyvaso, is an inhalant.


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