Secondary nonresponsiveness to new bulk botulinum toxin A (BCB2024)

Abstract

We report on a patient with cranio-cervical dystonia injected with the new, lower protein formulation of botulinum toxin A who developed secondary resistance to this toxin. Subsequent injections with botulinum toxin B provided substantial reduction of blepharospasm. This is the first reported case of secondary resistance to the new preparation of botulinum toxin A.