The project will consist of a multicenter, open-label, randomized study (PROBE design) in patients with CCM to be randomized in a 2:1 ratio (propranolol:control) and will allow comparison of 2 groups: one receiving propranolol (recommended initial dose is 40 mg bid, to be uptitrated to 80 mg bid, however, doses as low as 10 mg bid and up to 160 mg bid are acceptable according to tolerability) on the top of recommended standard care, the other receiving recommended standard care. This investigator-driven study will be open-label with a PROBE design will be applied so that each MRI exam will be centrally read and all adverse clinical events will be centrally adjudicated. It should be pointed out that by no means surgery, whenever indicated, will be delayed and/or avoided because of study treatment allocation.
The purpose of this exploratory trial is to test whether a chronic treatment with propranolol will reduce the burden of cerebrovascular lesions, of clinical events and symptoms in patients with familial CCM. Inherited CCM is a rare disease with a prevalence of less than 5/10.000. Thus, since the number of patients to be included in this exploratory trial will be insufficient to prove or disprove a statistically significant beneficial effect of propranolol on clinical events, the extension to more centers and patients is formally included in the present protocol. Special care will be paid to the biologic consistency of the different endpoints, even if none of them will yield statistically significant differences. The assessment of the tolerability of propranolol in normotensive otherwise healthy patients is another clinically relevant endpoint.
If the overall evaluation of the safety (no difference in AEs and SAEs between propranolol and control arms), and of the efficacy profile (assessed as consistency between incidence of adverse clinical events and magnetic resonance brain imaging results between propranolol and control arms) at the conclusion of the present study, will be reassuring for propranolol, a protocol for a definitive Phase 2 trial will be submitted for approval to Regulatory Authorities. This second trial may be designed as single-arm as far as adequate data on incidence of endpoint events will be available from Treat_CCM.