Objective:

To evaluate long-term safety and immunogenicity of up to 4 successive cervical dystonia (CD) treatments with DaxibotulinumtoxinA for Injection (DAXI; DAXXIFY™), a novel botulinum toxin (BoNT) type A with proprietary excipient peptide. 

Background:

DAXI previously demonstrated safety and efficacy in a randomized pivotal study, ASPEN-1.

Design/Methods:

Adults with moderate-to-severe CD were recruited from 65 study centers in the US, Canada, and Europe. Subjects received initial open-label DAXI 125U or 250U based on BoNT treatment history, CD severity, and investigator judgment; successive DAXI treatments could be 125U, 200U, 250U, or 300U. Per-muscle injected volume was within a pre-defined dose range. Re-treatment was based on loss of 80% of peak treatment effect or subject request and investigator judgment. Subjects were followed up to Week 52

Results:

357 subjects (271 from ASPEN-1, 86 de novo) received 985 DAXI treatments. Investigators placed 87% of subjects on at least 1 dose above 125U (≥250U, 77%; 300U, 37%). Commonly reported treatment-related treatment-emergent adverse events (TEAEs) (≥5% of subjects overall) were dysphagia, muscular weakness, and injection site pain. TEAE rates remained stable or decreased after repeat dosing. Treatment-related dysphagia was reported in 3.9%, 4.3%, 4.7%, and 3.1% of subjects in Cycles 1-4, respectively (4.2% of 985 DAXI treatments). There were no serious treatment-related TEAEs. The overall incidence of treatment-induced anti-drug antibodies was low, with no observed trend in incidence over successive doses.

Conclusions:

Repeat treatments with DAXI were safe and well tolerated, with a favorable immunogenicity profile.