Patient perspectives on the therapeutic profile of botulinum neurotoxin type A in cervical dystonia.

BACKGROUND: Botulinum neurotoxin type A (BoNT-A) is an effective pharmacological treatment for the management of cervical dystonia (CD) that requires repeated administration at variable intervals. We explored patient perceptions of the impact of CD and the waning of BoNT-A therapeutic effects. METHODS: An internet-based survey was conducted through Carenity, a global online patient community, from May to September 2019. Eligible respondents were adults with CD who had ≥ 2 previous BoNT-A injections. RESULTS: 209 respondents (81% females; mean age of 49.7 years) met the screening criteria. The mean BoNT-A injection frequency was 3.9 injections/year. The mean reported onset of BoNT-A therapeutic effect was 11.7 days and the time to peak effect was 4.5 weeks. Symptom re-emergence between injections was common (88%); the time from injection to symptom re-emergence was 73.6 days (~ 10.5 weeks). Treatment was not reported to completely abolish symptoms, even at peak effect. However, symptom severity was rated (0 = no symptoms; 10 = very strong symptoms) as lowest at the peak of treatment effects (mean scores ~ 3/10), increasing as the effects of treatment start waning (~ 5.5/10) and was strongest one day before the next session (~ 7-8/10). The impact of CD on quality of life followed the same 'rollercoaster' pattern. CONCLUSIONS: This survey highlights the burden of CD symptoms, even in patients undergoing regular treatment. Symptom re-emergence is common and has significant impact on daily activities and quality of life. Greater awareness of the therapeutic profile of BoNT-A treatment should lead to better informed therapeutic discussions and planning.