Myobloc® (rimabotulinumtoxinB) in the treatment of adult sialorrhea

Abstract

Introduction: Sialorrhea (drooling) can cause significant morbidity, including impaired oral hygiene, perioral irritation, embarrassment, swallowing impairment, and increased risk of aspiration, in several neurologic disorders. Local injections of botulinum toxin-B (BoNT-B) into the parotid and submandibular glands reduce saliva production. Methods: This double-blind, placebo-controlled (DBPC) study with open-label (OL) extension determined the efficacy, safety, and tolerability of repeat injections of BoNT-B for the treatment of sialorrhea. In the DBPC phase, adult subjects with Parkinson's disease, amyotrophic lateral sclerosis, medication-induced stroke, and other disorders were randomized (1:1:1) to receive MYOBLOC (rimabotulinumtoxinB) 2500 U vs 3500 U vs placebo. During the OL phase, all subjects received 3500 U during the first OL treatment cycle; dose adjustments were permitted in OL cycles 2 to 4 (injection interval, 11 to 15 weeks). Co-primary outcomes were change from baseline to week 4 in unstimulated salivary flow rate (USFR) and Clinical Global Impression of Change (CGI-C). Results: Of the 187 enrolled subjects, 176 completed the DBPC, 170 entered OL treatment, and 128 completed the OL phase up to 1 year. Treatment with rimabotulinumtoxinB in the DBPC study significantly reduced USFR at week 4 versus placebo (mean treatment effect, ‒0.30 for both doses vs placebo; P<0.0001). CGI-C scores were significantly better at week 4 for both treatment groups vs placebo (‒1.21 for 2500 U and ‒1.14 for 3500 U; both, P<0.0001). Treatment benefits were seen as early as week 1 and were maintained over repeat treatments for up to 1 year. The most frequent AE with rimabotulinumtoxinB was dry mouth (38% to 45%); in subjects who underwent repeat treatment, the incidence of AEs reduced over time. Conclusions: MYOBLOC provided effective treatment for sialorrhea in a DBPC multicenter trial. Long-term, repeat treatment with rimabotulinumtoxinB was effective in reducing sialorrhea in subjects for up to 1 year. Keywords: Botulinum toxin type B; Drooling; MYOBLOC; RimabotulinumtoxinB; Sialorrhea