The drug, ACT-078573, is the first oral orexin receptor antagonist that penetrates the blood-brain barrier and is capable of inducing a transient and reversible blockade of the two receptors, OX1 and OX2.
The study is a combined proof-of-concept/dose-finding study. As the per-protocol criteria for study continuation have been met, the study now has moved to the next stage and continues with the dose-finding part to establish the lowest effective dose.
“This finding exceeds our expectations. The magnitude of the observed effect clearly demonstrates that the orexin system plays a key role in insomnia patients. The study establishes in a highly significant way that when patients with primary insomnia received ACT-078573, they slept longer during the night compared to when they received placebo,” said Isaac Kobrin, head of Clinical Development at Actelion.
Actelion said a phase III trial in chronic insomnia could be initiated by year-end 2007.
Actelion said the phase III trial would not only focus on whether ACT-078573 induces and maintains sleep in insomnia patients, but will also attempt to demonstrate how antagonizing the orexin receptor could result in a different sleep and side effect profile compared to current sleep medications modulating the GABA-A receptor.