RimabotulinumtoxinB Reduces Sialorrhea in Adults

By Will Boggs MD

January 16, 2020

NEW YORK (Reuters Health) - RimabotulinumtoxinB (RIMA) safely reduces sialorrhea in adults, according to results from the phase 3 MYSTICOL clinical trial.

Sialorrhea, the excess spillage of saliva from the mouth, affects up to 74% of people with Parkinson's disease and up to half of patients with amyotrophic lateral sclerosis (ALS), and it is commonly seen in stroke survivors.

Injection of botulinum toxin into the salivary glands has been shown to inhibit saliva production, and both serotypes incobotulinumtoxinA and RIMA are approved in the US for management of sialorrhea in adults.

Dr. Stuart H. Isaacson from Parkinson's Disease and Movement Disorder Center of Boca Raton, Florida and colleagues evaluated the safety and efficacy of RIMA 2500 U and 3500 U in their randomized, placebo-controlled, 13-week clinical trial of 187 adults with sialorrhea related to Parkinson's disease (65.2%), stroke (7.0%), ALS (6.4%), medication use (3.2%), cerebral palsy (2.1%), and other causes (16.0%).

Both doses of RIMA significantly reduced unstimulated salivary flow rate (USFR) and improved Clinical Global Impression of Change (CGI-C) at four weeks, compared with placebo, according to the online report in JAMA Neurology.

Reductions in USFR and improvements in CGI-C compared with placebo began at week 1 and persisted through week 8. Reductions in USFR with the higher dose of RIMA persisted through the last office visit (week 11 to 15), whereas improvements in CGI-C with the lower dose of RIMA persisted to the study end.

These primary endpoints did not differ by the injection technique, cause of sialorrhea, severity of illness, sex, or age.

Most patients in both RIMA groups reported at least one adverse event, most commonly mild or moderate dry mouth, dysphagia, and dental caries.

"These data support the clinical use of RIMA for management of troublesome sialorrhea in adult patients," the authors conclude.

Dr. Paolo Banfi from Fondazione Don Carlo Gnocchi, Milan, Italy, who earlier reviewed options for treating sialorrhea in ALS, told Reuters Health by email, "Unfortunately, there is still no standardized saliva collection system today, with obvious bias. In fact, the saliva that wets the chin in these patients during the collection is not considered. The time at which the patients are taking the test isn't standardized for everyone."

"The end result did not surprise me," he said. "The botulinum effect on the salivary glands is well known."

US WorldMeds LLC funded the study, employed one of the 10 authors of the report, and had various relationships with the other nine authors.

Dr. Isaacson did not respond to a request for comments.

SOURCE: http://bit.ly/2NoWEWO JAMA Neurology, online January 13, 2020.