Volibris (ambrisentan) is a new endothelin-A-receptor antagonist for treatment of pulmonal arterial hypertension (PAH). Ambrisentan is dosed either as 5 mg or 10 mg once a day. Two randomised, double blinded and placebo controlled studies show that ambrisentan 5 mg and 10 mg gave a statistic significant improvement of the walking distance after 6 minutes, walk distances at respectively 45 meters and 51 meters, compared with placebo (p > 0,001).
The most frequent side effect was peripheral oedemas, which occurred in 17,3 % more in the treated group than in the placebo group.
The price of Volibris (ambrisentan) is equivalent to two other endothelin-receptor antagonists Tracleer (bosentan) and Thelin (sitaxentan) which costs 1.058 Dkr./DDD.
There has not been shown any greater effect or less number of side effects for ambrisentan than for bosentan and sitaxentan, even though ambrisentan appears to have a minor tendency to cause hepatotoxicity than bosentan and sitaxentan. The problems concerning interactions are unresolved.
IRF states that ambrisentan, bosentan and sitaxentan can all be used on the same level, if treatment with endothelin-receptor antagonists has been decided.