From 1 September 2024, mavacamten (Camzyos) will be reimbursed in Belgium for the treatment of obstructive hypertrophic cardiomyopathy.
In hypertrophic cardiomyopathy, there is excessive growth and overactivity of myocytes. Among other things, the protein myosin is overactive. This causes increased contractility and reduced relaxation of the myocytes. In some of these patients, this leads to a narrowing or obstruction of the outflow tract of the left ventricle under the aortic valve (LVOT, left ventricular outflow tract). These patients then have obstructive hypertrophic cardiomyopathy. Mavacamten is an oral cardiac myosin inhibitor. This reduces contractility and improves relaxation of these overactive myocytes. This reduces LVOT obstruction and dyspnea d'effort and improves prognosis. This was demonstrated in the EXPLORER-HCM trial.
The reimbursement criteria are:
- Clinical criteria:
- NYHA class II or III.
- Left ventricular wall thickness ≥ 15 mm (or ≥ 13 mm with a positive family history).
- Left ventricular ejection fraction (LVEF) ≥ 55% (according to echocardiography).
- At least one measurement of left ventricular outflow tract (LVOT) peak gradient ≥ 50 mmHg (at rest or after provocation (e.g. with stress echocardiography)), and Valsalva LVOT gradient ≥ 30 mmHg at the start of treatment.
- Resting oxygen saturation ≥ 90%.
- The patient must have been previously treated with a beta-blocker or a calcium channel blocker (verapamil or diltiazem). This treatment should be continued unless intolerance occurs.
- Genotyping for cytochrome P450 (CYP) 2C19 (CYP2C19) is required to determine the correct dose of Camzyos.
- Before starting treatment, women of childbearing potential must have a negative pregnancy test.
