Efficacy Remaining at Time of Requested Re-Treatment for Cervical Dystonia: A Potential New Treatment Paradigm with DaxibotulinumtoxinA.

The therapeutic efficacy remaining from prior treatments with botulinum toxins (BoNTs) when cervical dystonia (CD) patients prefer to be re-treated has not been well characterized. Here, we assessed the residual therapeutic efficacy of BoNT injections at the time of a patient-desired re-treatment. In pivotal trials for daxibotulinumtoxinA (DAXI) in CD, subjects could request re-treatment before returning to pre-treatment symptom levels (defined as ≤20% of peak efficacy remaining). In this post hoc analysis of the Phase 3 ASPEN-OLS trial, the median percent efficacy remaining (based on change in TWSTRS total score) was determined in subjects who requested re-injection before returning to pre-treatment symptoms. Dysphagia and muscle weakness were evaluated in patients requesting re-treatment with efficacy remaining, relative to those waiting to return to baseline. There were 264 (28.7% of 920 total treatments) patient requests for re-treatment before returning to pre-treatment status across the study. The median percent efficacy remaining at the time of requested re-injection was 45.5%, which corresponded to a median of 16.0 weeks (range 10.9-40.3) post-treatment. The rates of dysphagia (≤4.9%) and muscle weakness (≤6.8%) were low and were not significantly different in those who waited for return to pre-treatment symptom status versus subjects who requested re-injection with efficacy remaining. A significant proportion of CD patients wished to be re-treated with efficacy still remaining from prior BoNT injections as early symptoms re-emerged. With the overall clinical profile of DAXI, physicians can safely provide individualized treatment regimens based on the treatment goals or symptomatic needs of their patients.