Background:
Botulinum toxin-A is a well-established treatment for adult and pediatric
spastic paresis and
cervical dystonia. While guidelines and approved labels indicate that treatment should not occur more frequently than every 12 weeks, studies and real-world evidence show that the timing of symptom recurrence between treatments may vary. Methods: We report
retreatment criteria and response duration (
retreatment intervals) from four pivotal, double-blind, placebo-controlled studies with open-label extensions involving patients treated with
abobotulinumtoxinA (aboBoNTA) for upper limb (NCT01313299) or lower limb (NCT01249404)
spastic paresis in adults, lower limb
spastic paresis in children (NCT01249417), and
cervical dystonia in adults (NCT00257660). We review results in light of recently available preclinical data. Results: In
spastic paresis, 24.0-36.9% of upper limb patients treated with aboBoNTA and 20.1-32.0% of lower limb patients did not require
retreatment before 16 weeks. Moreover, 72.8-93.8% of aboBoNTA-treated pediatric patients with lower limb
spastic paresis did not require
retreatment before 16 weeks (17.7-54.0% did not require
retreatment before 28 weeks). In aboBoNTA-treated patients with
cervical dystonia, 72.6-81.5% did not require
retreatment before 16 weeks. Conclusion: AboBoNTA, when dosed as recommended, offers symptom relief beyond 12 weeks to many patients with
spastic paresis and
cervical dystonia. From recently available preclinical research, the amount of active
neurotoxin administered with aboBoNTA might be
a factor in explaining this long duration of response.