zamicastat + bosentan

A **combination of zamicastat and bosentan** intended for the treatment of pulmonary arterial hypertension (PAH) and related cardiovascular conditions. **Zamicastat** is a small molecule, selective dopamine beta-hydroxylase inhibitor that reduces the synthesis of norepinephrine from dopamine, potentially reducing sympathetic overactivity. It is being developed primarily for hypertension, heart failure, and has an orphan drug status for PAH. **Bosentan** is an oral dual endothelin receptor antagonist (ERA) approved for PAH, working by blocking the effects of endothelin-1, a vasoconstrictive peptide, to lower pulmonary vascular resistance and slow disease progression. This combination targets two distinct pathways: sympathetic nervous system modulation (via zamicastat) and endothelin-mediated vasoconstriction (via bosentan). Clinical trials and literature focus mainly on combinations of bosentan with PDE5 inhibitors for PAH; data on zamicastat with bosentan is extremely limited or in early clinical stages.