Fig. 1

Mean change from baseline in frequency of headache days. Patient-reported estimate of number of days in a month with a headache (≥4 h) at each administration visit through visit 8.^† Mean (SD) headache-day frequency at baseline was 20.6 (5.4) days per month. *P < 0.001 Wilcoxon signed rank test for change versus baseline (level of significance: 5%). ^†The numbers of patients in administration (Admin) visits 9–13 were as follows: Admin 9, n = 119; Admin 10, n = 50; Admin 11, n = 24; Admin 12, n = 13; Admin 13, n = 7. Mean changes from baseline for Admin visits 9–13 were each significant (Admin 9–12, P < 0.001; Admin 13, P = 0.016)