Prognosis Following Discontinuation of OnabotulinumA Therapy in "Super-responding" Chronic Migraine Patients.

[OBJECTIVE] To determine whether the successful treatment of chronic migraine (CM) with onabotulinumA (BotoxA) may be followed by a continued respite from headache once therapy has been discontinued.

[BACKGROUND] The optimal duration of prophylactic therapy for migraine generally and for CM treated with BotoxA specifically is unknown.

[METHODS] We conducted a prospective cohort study evaluating a series of patients with CM at a university-affiliated headache subspecialty clinic in Reno, Nevada, all of whom were treated according to a uniform protocol involving serial injections of BotoxA. We followed all positively responding patients who met our stopping rule for a minimum of 6 months after discontinuation of BotoxA, and we assessed the incidence of clinical worsening in that group.

[RESULTS] A total of 105/131 patients (80%) for whom complete follow-up was available reported no clinical worsening or need to resume prophylactic therapy over the 6 months following discontinuation of BotoxA therapy. Patients with pre-treatment baseline chronic daily headache (CDH) of greater than 6 months duration were more likely to report clinical deterioration within 6 months of stopping treatment, as compared to patients with CDH of less than 6 months. A greater number of BotoxA treatments required to achieve our stopping rule correlated with clinical deterioration within 6 months of stopping treatment.

[CONCLUSIONS] In many CM patients who experience an especially positive response to serial BotoxA injection therapy, clinical improvement may be sustained for a period of at least 6 months following discontinuation of prophylactic therapy.