An investigational new drug for pulmonary hypertension may improve the quality of life for thousands of patients with scleroderma, lupus, and other associated connective tissue diseases, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in San Antonio, Texas.
Lupus, scleroderma and related connective tissue diseases are chronic inflammatory autoimmune diseases that can damage the blood vessels of the lung and other organs. Pulmonary hypertension, which is high blood pressure in the lungs, is a common and potentially devastating complication of these diseases that causes hearth failure, inability to exercise and ultimately to the death of about half of the patients with this complication within two to three years after diagnosis. P atients with pulmonary hypertension have elevated levels of endothelin, a powerful blood vessel constrictor, in their plasma and lung tissue.
Researchers conducted a multicenter, randomized, double-blind, placebo-controlled trial of sitaxsentan, a once-daily oral endothelin receptor antagonist which blocks the action of endothelin on blood vessels to determine whether it could improve the ability of pulmonary hypertension patients to exercise without difficulty. This 12-week trial involved 178 patients with pulmonary hypertension, 42 of whom had pulmonary hypertension related to a connective tissue disease. Patients received either 100mg or 300 mg of sitaxsentan, or placebo, for 12 weeks. All patients participated in the 6-minute walk test, the standard test for treatments for pulmonary hypertension that measures how far an individual can walk in six minutes, before the treatment began and again at the end of the 12-week trial. Researchers found that patients with pulmonary hypertension related to connective tissue disease who were taking either the 100mg or 300mg dosage significantly improved their walking distance as compared to those taking placebo (whose time actually worsened).
"Sitaxsentan was shown to significantly improve six-minute walk distance, as well as hemodynamics such as cardiac index and pulmonary vascular resistance for patients with pulmonary hypertension related to connective tissue disease," said lead investigator Vallerie McLaughlin, MD, University of Michigan Hospital, Ann Arbor, Michigan. "The first therapy shown to improve key efficacy variables in this population was epoprostenol, a prostacyclin therapy that requires a central catheter and continuous intravenous infusion that is often difficult for patients to tolerate. Thus, the ability of an oral, once daily therapy such as sitaxsentan sodium to improve key efficacy variables represents an important treatment advance."
The American College of Rheumatology is the professional organization for rheumatologists and health professionals who share a dedication to healing, preventing disability and curing arthritis and related rheumatic and musculoskeletal diseases.
For more information on the ACR's annual meeting, see http://www.rheumatology.org/annual.