A drug widely used as a therapy for pulmonary hypertension (PH) is now available in intravenous (IV) form. Remodulin (treprostinil sodium), manufactured by United Therapeutics, has been available to people with PH since 2002 in the form of a continuous subcutaneous (under the skin) infusion. Last week, the Food and Drug Administration gave its approval for the IV form of the drug based on data establishing its bioequivalence with the subcutaneous version.
United Therapeutics says the drug is immediately available for commercial intravenous use.
"It gives us great satisfaction to make available this new route of delivery for our prostacyclin analog, Remodulin," said Martine Rothblatt, PhD, United Therapeutics' chairman and CEO.
What Are Prostacyclins?
Prostacyclin acts like a natural substance that occurs naturally in the body known as prostaglandin I2. Studies have shown that people with primary pulmonary hypertension don't make enough of this prostacyclin-like substance. In addition to Remodulin, the drug, Flolan (epoprostenol/GlaxoSmithKline) falls in the same category of drugs.
Prostacyclin dilates blood vessels, reduces blood clotting by keeping platelets from clumping together, improves cardiac output, and slows the growth of smooth muscle cells, a characteristic of PH.1
Both Remodulin and Flolan are delivered by catheters attached to small pumps. Remodulin is funneled into the fat under the skin covering the stomach.1
Another Option for Patients
The drug is being offered in IV form due to certain side effects that some patients experience with the subcutaneous form of the drug, Rothblatt explained. "For many hundreds of patients, subcutaneous Remodulin is the answer, as it frees them from the indwelling catheter which is characteristic of Flolan," he said, in a conference call with investors last week. "However, over the past couple of years, we've seen that about a third of the patients who transition to Remodulin drop off of therapy due to intolerable site pain."
As such, IV Remodulin "is an improvement over both Flolan and subcutaneous Remodulin," Rothblatt said.
In addition to providing an answer to patients who experience site pain with subcutaneous Remodulin, the IV form of the drug allows patients to avoid mixing and ice packs, is stable at room temperature, and has a longer half-life than Flolan, Rothblatt stated.
Phase IV Trial Underway
The FDA's approval letter did not request additional clinical trials of IV Remodulin, nor any additional data. United Therapeutics, nonetheless, is continuing a post-marketing Phase IV trial as a condition of the government's accelerated approval of this delivery method. A final study report is due out in late 2005, the company said.
Rothblatt says pricing for IV Remodulin will remain the same as the subcutaneous version. "There's also a strong sentiment among PH physicians that average dosing of Remodulin, both subcutaneous and IV, will actually moderate over time with the introduction of combination therapies, such as sildenafil [Viagra] and endothelin receptor antagonists … and bring prices down," he said, quickly adding that this is currently a hypothetical scenario.
"I think we're entering a very exciting period when many things will be tried in the clinic—many combinations—and the winner will be the patient," Rothblatt said.
1. Pulmonary Hypertension Association. Pulmonary Hypertension Association: A Patient's Survival Guide. 2nd Ed; 2001.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include coverage of health news for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
