Botulinum toxin safe and effective for spasmodic dysphonia treatment: BOISS Study

Japan: Botulinum toxin injection into laryngeal muscles is safe and effective for the treatment of spasmodic dysphonia (SD), finds a recent study in the European Journal of Neurology.

Botulinum toxin injection is an accepted standard treatment for SD and this study provides additional data for safety and efficacy of this treatment, note the authors.

SD is a rare form of focal dystonia that occurs in the absence of phonatory organ paralysis or other structural pathology. It is characterized by involuntary intermittent spasms of the intrinsic laryngeal muscles. BT injection has been standard treatment for spasmodic dysphonia. However, only a few high‐quality clinical studies have appeared, and BT is used off‐label in most countries.

Masamitsu Hyodo, Kochi University, Nankoku, Japan, and colleagues performed a multicenter, placebo‐controlled, randomized, double‐blinded, parallel‐group comparison/open‐label clinical trial (the BOtulinum toxin Injection therapy for Spasmodic dySphonia [BOISS], study).

The study aimed at obtaining approval for BT therapy for SD in Japan. This is the first clinical trial based on Good Clinical Practice (GCP) guidelines to be conducted on BT worldwide.