Observational, open-label, non-randomized study on the efficacy of onabotulinumtoxinA in the treatment of nummular headache: The pre-numabot study

Abstract

Background Nummular headache is a primary headache characterised by superficial, coin-shaped pain. Superficial sensory fibre dysfunction might be involved in its pathophysiology. Considering the mechanism of action of onabotulinumtoxinA, it could be a reasonable option in treatment of nummular headache. The aim of the study was to evaluate the efficacy and tolerability of onabotulinumtoxinA in a series of nummular headache patients. Patients and methods This was an observational, prospective, non-randomized and open-label study. Nummular headache patients with at least 10 headache days in three preceding months were included. They were administered 25 units of onabotulinumtoxinA. The primary endpoint was the decrease of headache days per month, evaluated between weeks 20 to 24, compared with baseline. The secondary endpoints included reduction of intense headache days and acute treatment days evaluated between weeks 20–24 and weeks 8–12, compared with baseline. The 30%, 50% and 75% responder rates were determined, and tolerability described. Results We included 53 patients, 67.9% females, with a median age of 54 years. Preventive treatment had been used previously in 60.4% of patients. The median diameter of the nummular headache was 5 cm. At baseline, the number of headache days per month was 24.5 (7.3); the number of intense headache days was 12.5 (10.1), and the number of acute treatment days was 12.8 (7.8). After onabotulinumtoxinA, the mean number of headache days per month decreased to 6.9 (9.3) between weeks 20 and 24 ( p < 0.001). Secondary endpoints concerning intense headache days per month and acute treatment days per month were also statistically significant ( p < 0.001). The 50% responder rate, evaluated between weeks 20 and 24, was 77.4% and the 75% responder rate was 52.8%. Concerning tolerability, 26 patients (49.1%) experienced an adverse event (AE), the commonest being injection-site pain in 12 cases (22.6%). There were no moderate or severe AEs. Conclusion It was found that after injecting onabotulinumtoxinA, the number of headache days per month was reduced in nummular headache patients. The number of intense headache days per month and acute treatment days were also lowered. No serious adverse events occurred during treatment.