Upfront Triple Combination Therapy Shows Promise In Severe Pulmonary Arterial Hypertension

A small pilot study by a team of French researchers has established the long-term benefits of upfront triple combination therapy among patients with severe pulmonary arterial hypertension (PAH)

The U.S. National Library of Medicine (NLM) describes pulmonary arterial hypertension as abnormally high blood pressure in the arteries of the lungs that makes the right side of the heart work harder than normal. The right side of the heart pumps blood through the lungs, where it picks up oxygen. Blood returns to the left side of the heart, where it is pumped to the rest of the body. When the small arteries (blood vessels) of the lung become narrowed, they cannot carry as much blood. When this happens, pressure builds up — called pulmonary hypertension. The heart needs to work harder to force blood through the vessels against this pressure, and over time, this causes the right side of the heart to become larger. Ultimately, heart failure affects the right side of the heart. This is called cor pulmonale.

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The NLM says pulmonary hypertension may be caused by autoimmune diseases that damage the lungs, such as scleroderma and rheumatoid arthritis, birth defects of the heart, blood clots in the lung (pulmonary embolism), heart failure, heart valve disease, HIV infection, low oxygen levels in the blood for a long time (chronic), lung disease, such as COPD or pulmonary fibrosis, medicines (for example, certain diet drugs), and obstructive sleep apnea, but in many patients, the cause of pulmonary hypertension is unknown. In that case, the condition is called idiopathic pulmonary arterial hypertension (IPAH). IPAH is rare, and affects more women than men. If pulmonary hypertension is caused by a known medicine or medical condition, it is called secondary pulmonary hypertension.

A report of the French scientists’ findings is published online before print in the European Respiratory Journal. “Upfront triple combination therapy in pulmonary arterial hypertension: a pilot study” (doi: 10.1183/09031936.00116313 ERJ March 13, 2014 erj01163-2013) notes that patients with severe pulmonary arterial hypertension (PAH) in New York Heart Association (NYHA) functional class (FC) III/IV have a poor prognosis, despite survival benefits being demonstrated with intravenous epoprostenol.

In this pilot study, co-authored by Olivier Sitbon of the Université Paris-Sud, Le Kremlin-Bicêtre and a team of 12 other co-researchers the from nine French medical research institutions and universities, investigated the efficacy and safety of a triple combination therapy regimen in patients with severe pulmonary arterial hypertension (PAH).

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They note that patients with severe PAH in the New York Heart Association (NYHA) functional class (FC) III/IV have a poor prognosis, despite survival benefits being demonstrated with intravenous epoprostenol. In this pilot study, the efficacy and safety of a triple combination therapy regimen in patients with severe PAH was investigated. Data from newly diagnosed NYHA FC III/IV PAH patients (n = 19) initiated on upfront triple combination therapy: intravenous epoprostenol (up to a maximum of 16 ng/kg per minute), bosentan (125 mg twice daily), and sildenafil (20 mg three times daily) between December 2007 and July 2013 were collected retrospectively from a prospective registry. The most commonly reported adverse events were jaw pain, manageable headache, diarrhea, and flushing — all reportedly typical of epoprostenol therapy. Two patients discontinued bosentan (at 11.5 and 31.5 months) due to asymptomatic liver enzyme elevation, but were maintained in FC I/II using epoprostenol and sildenafil.

The scientists report that significant improvements in 6-minute walk distance and haemodynamics were observed after 4 months’ triple combination therapy in 18 patients (p<0.01); 17 patients had improved to NYHA FC I or II. One patient was not included in the month 4 assessment (due to an emergency heart and lung transplant in month 3). At the final evaluation (mean±SD 32±19 months), all 18 patients had sustained clinical and haemodynamic improvement. Overall survival estimates for the triple combination cohort were 100% at 1, 2 and 3 years. Expected survival calculated from the French equation was 75% (95% CI 68–82%), 60% (95% CI 50–70%) and 49% (95% CI 38–60%) at 1, 2 and 3 years, respectively.

The researchers conclude that this pilot study provides preliminary evidence of the long-term benefits of upfront triple combination therapy in patients with severe PAH.

Full text of the European Respiratory Journal article is available at: http://goo.gl/T4gsed

Sources:
European Respiratory Journal
U.S. National Library of Medicine