[en] Introduction: Anti-CGRP have proven to be an effective and well-tolerated treatment for migraines. However, up to 60% of patients will not have a satisfactory response. In these cases, given the scarce therapeutic alternatives, the switch to another anti-CGRP has been proposed as an option, although there is little evidence in this regard. Objective: To determine the effectiveness of switching to a second antiCGRP after the therapeutic failure of the first in patients with high-frequency episodic migraine or chronic migraine. Methodology: In May 2024, a systematic search was conducted for studies that analyzed the effectiveness of switching to a second anti-CGRP after the therapeutic failure of the first, published since 2018. The PubMed, Embase and Scopus databases were reviewed; and the "snowball" technique was applied. Meta-analyses, systematic reviews, clinical trials and observational studies were included; published in English or Spanish. Results: 69 results were obtained. After the selection process, 14 studies were included in the final review. All the studies found are observational (11 cohorts and 3 case series). In total, the studies add up to a sample size of 511 patients. Most analyze the switch from a specific receptor antibody (Erenumab) to a specific ligand antibody (Galcanezumab, Fremanezumab or Eptinezumab). The studies show at least a partial response at 3 months in approximately 1/3 of the patients. Conclusions: The available evidence suggests that there is a possible benefit in switching to a second anti-CGRP. However, this evidence is not robust as it is based solely on observational studies. Controlled clinical trials would be needed to provide quality evidence and determine the real effectiveness of the switch.

[gl] Introdución: Os anti-CGRP demostraron ser un tratamento eficaz e ben tolerado na migraña. Porén, ata un 60% dos pacientes non presentarán unha resposta satisfactoria. Nestes casos, dadas as escasas alternativas terapéuticas, propúxose como opción o cambio por outro anti-CGRP, aínda que existe escasa evidencia ao respecto. Obxectivo: Determinar a eficacia do cambio a un segundo anti-CGRP tras o fracaso terapéutico do primeiro en pacientes con migraña episódica (ME) de alta frecuencia ou migraña crónica (MC). Metodoloxía: En maio de 2024 realizouse unha busca sistemática de artigos que analizasen a eficacia do cambio a un segundo anti-CGRP tras o fracaso terapéutico dun primeiro, publicados dende o ano 2018. Revisáronse as bases PubMed, Embase e Scopus; e aplicouse a técnica "bola de neve". Incluíronse metaanálises, revisións sistemáticas, ensaios clínicos e estudos observacionais; publicados en inglés ou castelán. Resultados: Obtivéronse 69 resultados. Tras o proceso de selección, 14 estudos foron incluídos na revisión final. Todos os estudos atopados son observacionais (11 cohortes e 3 series de casos). En total os estudos suman un tamaño da mostra de 511 pacientes. A maior parte analizan o cambio dun anticorpo específico contra receptor (Erenumab) a un anticorpo específico contra ligando (Galcanezumab, Fremanezumab ou Eptinezumab). Os estudos demostran unha resposta polo menos parcial aos 3 meses en aproximadamente 1/3 dos pacientes. Conclusións: A evidencia dispoñible suxire que existe un posible beneficio no cambio por un segundo anti-CGRP. Porén, dita evidencia non é robusta ao basearse unicamente en estudos observacionais. Necesitaríanse ensaios clínicos controlados que aporten evidencia de calidade e permitan determinar a efectividade real do cambio.