Combination therapy with ambrisentan (Letairis) and tadalafil (Adcirca, Cialis) can significantly reduce the risk of clinical-failure events for pulmonary arterial hypertension (PAH) patients compared with either drug alone, according to complete results from a clinical trial published in the New England Journal of Medicine.

Risk of first clinical failure — defined as either death, hospitalization for worsening PAH, disease progression or unsatisfactory long-term clinical response to medication — was reduced by half in the combination therapy group versus the two single therapy groups combined (hazard ratio 0.50; 95% CI 0.35-0.72).

“One of the dominant questions in pulmonary hypertension has been ‘Is there an imperative to start multiple agents at the same time?'”¬†Jeremy Feldman, MD, director of the pulmonary hypertension program at Arizona Pulmonary Specialists in Phoenix told MedPage Today. “That has been a point of religion and conjecture until the results of the AMBITION study were released. Now we have really concrete, A-plus evidence that there are clear benefits to the upfront combination therapy.”