Key messages

• Migraine patients having failed more than four conventional prophylactic medications have been excluded from clinical studies assessing novel CGRP mAb therapies.
• Preliminary results of a highly refractory population typically seen in specialized headache clinics and treated with monthly 140 mg erenumab are presented.
• After 6 months of treatment with erenumab, this small case series illustrates a beneficial ≥50% reduction in frequency of migraine headache days in patients having failed up to seven preventative drugs.