We sought to assess the effectiveness of combining dual therapy with onabotulinumtoxinA (BTX) add-on to anti-calcitonin gene-related peptide (CGRP) monoclonal antibodies (anti-CGRP MAbs) in treatment-refractory patients with chronic migraine (CM). We retrospectively reviewed the medical files of 19 treatment-refractory patients with CM who had failed to two oral migraine preventatives, at least three consecutive BTX cycles (less than 30% response rate), at least three consecutive sessions with either fremanezumab or erenumab (less than 30% response rate), and were eventually switched to dual therapy with BTX add-on to any of the already-given anti-CGRP MAbs. We then assessed from baseline to each monotherapy or dual intervention predefined efficacy follow-up the changes in the following efficacy outcomes: (i) monthly headache days (MHD), (ii) monthly days with moderate/severe peak headache intensity, and (iii) monthly days with intake of any acute headache medication. Response (50% reduction in MHD) rates, safety, and tolerability were also determined. In the majority of cases (n = 14), dual targeting proved effective and was associated with clinically meaningful improvement in all efficacy variables; 50% response rates (also disability and QOL outcomes) coupled with favorable safety/tolerability. Our results advocate in favor of the view that dual therapy is effective and should be considered in difficult-to-treat CM patients who have failed all available monotherapies.
Keywords: anti-CGRP monoclonal antibodies; chronic migraine; dual therapy; onabotulinumtoxinA; treatment-refractory migraine.