Pivotal Pulmonary Arterial Hypertension Study Published in The Lancet Concludes That Bosentan (Tracleer(R)) Demonstrates Benefits in Patients With Mildly Symptomatic WHO Functional Class ...(co-primary endpoints were changes inpulm...),Health

A highly significant reduction in PVR of 22.6% (p <0.0001) and a significant 77% risk reduction in delaying the time to clinical worsening (p = 0.011) were seen after six months of bosentan treatment compared with placebo. Time to clinical worsening, defined by death, hospitalization for PAH and symptomatic progression of PAH, showed that more patients remained stable without signs of deterioration in the bosentan-treated group compared with placebo (3.4% vs. 13.2%, p = 0.029). In addition, a significant delay in WHO functional class deterioration was observed in the bosentan group compared with placebo, providing further evidence of delayed disease progression. The improvement in 6MWD did not reach statistical significance (p = 0.076). This may reflect the fact that, on average, patients in EARLY had a relatively well-preserved exercise capacity, which therefore can be more difficult to improve.

The safety and tolerability profile of bosentan was consistent with that observed in previous placebo-controlled clinical trials.(2, 3)

Professor Gerald Simonneau, Hopital Antoine Beclere, Universite Paris-Sud, France commented: "The results from EARLY show the relentlessly progressive nature of PAH, even in its early stages. It is of paramount importance to screen high risk patients to attain a timely diagnosis and then to treat these patients with an evidence-based approach. It is also crucial that all PAH patients, regardless of functional class, are routinely monitored for the earliest signs and symptoms of PAH progression."

A subgroup of patients who received concomitant sildenafil showed improvements in PVR and 6MWD consistent with the overall results.

Further evidence of the effect of bosentan on hemodynamics is provide
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