WHAT IS KNOWN AND OBJECTIVE?: Erenumab and galcanezumab have shown great results for migraine prevention. However, strict inclusion criteria, absence of concomitant medication and selective outcome report of clinical trials may sometimes be barely representative of the real-world daily practice. Therefore, this study was designed to evaluate effectiveness and safety of these two monoclonal antibodies targeting calcitonin gene-related peptide in real-world patients. METHODS: This observational, retrospective study evaluated the effectiveness and safety of erenumab 140 mg and galcanezumab 120 mg in 142 real-world patients who had previously not responded to three well-established pharmacological alternatives for migraine prevention. To do so, a combination of objective parameters (monthly headache days and acute migraine-specific medication days) and subjective measurements (Migraine Disability Assessment questionnaire, Headache Impact Test and Visual Analogue Scale), validated for clinical research in migraine, were assessed during clinical interview. RESULTS AND DISCUSSION: Findings here reported show that erenumab and galcanezumab reduced monthly headache days, acute migraine specific medication days per month, Headache Impact Test score, Migraine Disability Assessment Test score and Visual Analogue Scale score after 3 and 6 doses (p < 0.01). Additionally, more than 25% of the patients enrolled in the study experienced a reduction by a half in monthly headache days, and more than 50% of the patients also reported a reduction by a half in the number of migraine specific medication days. Both treatments exhibited a great safety profile, rarely leading to discontinuation because of poor tolerance. WHAT IS NEW AND CONCLUSIONS?: Altogether, these results support previous real-life studies regarding effectiveness and safety and provide an interesting insight in how these preventive therapies are also effective in patients diagnosed with difficult to treat migraine who have previously failed, at least, three different drug classes stablished by current neurology guidelines for migraine prevention. Moreover, these data may suggest that erenumab and galcanezumab are able to not only diminish frequency, but also migraine intensity, and that it should be also considered as an effectiveness measure in line with other authors suggestion.