LAS VEGAS – Scleroderma patients are at particularly high risk for developing pulmonary arterial hypertension, but treatment options are expanding, and with early referral to a PAH specialist, outcomes can be improved, according to Dr. Ronald J. Oudiz.
"In 1995 we had nothing. Now we have nine treatments specifically for PAH, and more that are being looked at," he said at Perspectives in Rheumatic Diseases 2013.
Three major signaling pathways, including the prostacyclin, endothelin, and nitric oxide pathways, form the basis for the available treatment options for this progressive and deadly disease, which has a 36-month survival rate of only about 60%. The treatments include prostacyclin analogues, endothelin receptor antagonists, and phosphodiesterase type 5 (PDE-5) inhibitors, said Dr. Oudiz, professor of medicine at the University of California, Los Angeles, and director of the Liu Center for Pulmonary Hypertension at Harbor-UCLA Medical Center.
The prostacyclin analogues include intravenous epoprostenol, inhaled iloprost, and treprostinil, which can be inhaled or delivered intravenously or subcutaneously. These have been shown to improve performance on the 6-minute walk test in a dose-dependent fashion, Dr. Oudiz noted.
Side effects with prostacyclin analogues can include flushing, headache, rash, thrombocytopenia, infection, and gastrointestinal effects such as diarrhea, nausea, and weight loss.
The endothelin receptor antagonists include bosentan and ambrisentan, which both are delivered orally. Their approval was "revolutionary, because for a while we only had IV drugs," he said.
Side effects with endothelin receptor antagonists include liver function test abnormalities, headache, nasal congestion, and edema. Although these drugs are generally tolerated well, liver function test abnormalities and edema can be troublesome for both patients and physicians as they require close monitoring and dose modification or interruption, he said.
PDE-5 inhibitors include sildenafil and tadalafil, which also are both oral drugs, and which have side effects that are similar to those seen with the endothelin-receptor antagonists, with the addition of myalgia, diarrhea, dyspepsia, and nose bleeds, he noted.
Overall, studies suggest that treatment with PAH drugs not only leads to improved exercise capacity, but probably improves long-term survival. In a meta-analysis of several major PAH drug trials, the majority of studies showed a potential mortality benefit (Eur. Heart. J. 2009;30:394-403), Dr. Oudiz noted.
"I say potential because we know none of the studies assessed in the meta-analysis were powered to examine mortality ... but nevertheless, we believe we’re doing more than just improving exercise capacity," he said.
In fact, in a study published in August in the New England Journal of Medicine, the new endothelin receptor antagonist macitentan was associated with a dose-dependent decrease in the number of outcome events measured, relative to placebo, including death, transplant, and heart failure in patients with PAH, he noted (N. Engl. J. Med. 2013;369:809-18).
"These are some really important endpoints we’re finally starting to meet," he said.
These advances underscore the importance of increased awareness of the risk of PAH in scleroderma and early recognition of the condition, and – since diagnosis and the subtleties of management are complex – they also underscore the importance of early referral to a PAH specialist, he said.
"Early treatment is always preferable to later treatment," he concluded at the meeting held by Global Academy for Medical Education. GAME and this news organization are owned by Frontline Medical Communications.
Dr. Oudiz has received grant or research support from, served as a consultant to, and/or served on a speakers’ bureau for Actelion, Bayer, Gilead, Ikaria, Lung, Pfizer, and United Therapeutics.