doi:10.3389/fneur.2024.1417831engNavarro-Pérez, María PilarGonzález-Quintanilla, VicenteMuñoz-Vendrell, AlbertMadrigal, ElisabetAlpuente, AliciaLatorre, GermánMolina, FrancisMonzón, María JoséMedrano, VicenteGarcía-Azorín, DavidGonzález-Oria, CarmenGago-Veiga, AnaVelasco, FernandoBeltrán, IsabelMorollón, NoemíViguera, JavierCasas-Limón, JavierRodríguez-Vico, JaimeCuadrado, ElisaIrimia, PabloIglesias, FernandoGuerrero-Peral, Ángel LuisBelvís, RobertPozo-Rosich, PatriciaPascual, JulioSantos-Lasaosa, SoniaLong-term safety of OnabotulinumtoxinA treatment in chronic migraine patients: a five-year retrospective studyART-2024-139155Background: Real-world studies have shown the sustained therapeutic effect and favourable safety profile of OnabotulinumtoxinA (BoNTA) in the long term and up to 4 years of treatment in chronic migraine (CM). This study aims to assess the safety profile and efficacy of BoNTA in CM after 5 years of treatment in a real-life setting. Methods: We performed a retrospective chart review of patients with CM in relation to BoNTA treatment for more than 5 years in 19 Spanish headache clinics. We excluded patients who discontinued treatment due to lack of efficacy or poor tolerability. Results: 489 patients were included [mean age 49, 82.8% women]. The mean age of onset of migraine was 21.8 years; patients had CM with a mean of 6.4 years (20.8% fulfilled the aura criteria). At baseline, patients reported a mean of 24.7 monthly headache days (MHDs) and 15.7 monthly migraine days (MMDs). In relation to effectiveness, the responder rate was 59.1% and the mean reduction in MMDs was 9.4 days (15.7 to 6.3 days; p < 0.001). The MHDs were also reduced by 14.9 days (24.7 to 9.8 days; p < 0.001). Regarding the side effects, 17.5% experienced neck pain, 17.3% headache, 8.5% eyelid ptosis, 7.5% temporal muscle atrophy and 3.2% trapezius muscle atrophy. Furthermore, after longer-term exposure exceeding 5 years, there were no serious adverse events (AE) or treatment discontinuation because of safety or tolerability issues. Conclusion: Treatment with BoNTA led to sustained reductions in migraine frequency, even after long-term exposure exceeding 5 years, with no evidence of new safety concerns.2024http://zaguan.unizar.es/record/13619710.3389/fneur.2024.1417831http://zaguan.unizar.es/record/136197oai:zaguan.unizar.es:136197Frontiers in Neurology 15 (2024), [7 pp.]byhttps://creativecommons.org/licenses/by/4.0/deed.esinfo:eu-repo/semantics/openAccess