FDA Approves Myobloc Injection for Chronic Drooling in Adults

Myobloc (rimabotulinumtoxinB) injections have been approved by the U.S. Food and Drug Administration (FDA) to treat adults with chronic sialorrhea, or drooling, a condition that’s often experienced by patients with cerebral palsy.

Sialorrhea, commonly known as drooling, refers to an overflow of saliva production. The condition often occurs in many neurological disorders, including neuromuscular diseases such as amyotrophic lateral sclerosis and cerebral palsy, and neurodegenerative diseases such as Parkinson’s disease.

“Sialorrhea can be highly distressing for patients and their caregivers and can have a significant, negative impact on quality of life,” Stuart Isaacson, MD, Director of the Parkinson’s Disease and Movement Disorder Center of Boca Raton, said in a news release.

Myobloc, marketed by US WorldMeds, is the first botulinum toxin type B approved for sialorrhea. Injections are given by healthcare professionals directly into two of the major glands that produce saliva, the parotid and submandibular glands.

According to the company, a single dose can significantly reduce drooling within one week of treatment and remain effective for up to three months.

Myobloc works by blocking the transmission of certain nerve signals to muscles and salivary glands. Specifically, it inhibits the release of the neurotransmitter acetylcholine, a chemical substance involved in the activation of sweat and salivary glands.

Myobloc has already been approved as an intramuscular injection to treat the abnormal head position and neck pain that occurs in adults with cervical dystonia.

Its approval for chronic sialorrhea came under a supplemental Biologics License Application (sBLA) that was supported by clinical trials, including a multicenter Phase 2 study (NCT00515437) in 54 Parkinson’s patients with sialorrhea.

During the trial, participants were randomized to receive either Myobloc or a placebo. Myobloc was injected first into the submandibular glands, and then into the parotid glands. Salivary production and symptomatic relief were measured.

Results revealed gastrointestinal‐related adverse events occurred more frequently in Myobloc-treated patients (31%) than in placebo-treated participants (7%), with dry mouth being the most common event (15%). No serious side effects were attributed to botulinum toxin type B.

The study found saliva production was significantly reduced and symptoms attenuated, in a dose-dependent manner, four weeks after a single Myobloc injection, compared with a placebo. The therapy’s safety and efficacy were further confirmed by subsequent dosing sessions for over one year.

“We are committed to helping patients who struggle with confidence due to their sialorrhea. This new indication for Myobloc offers a fast-acting and proven treatment,” P. Breckinridge Jones, CEO of US WorldMeds, said. “We are proud to support health care providers with an option that can have such a positive impact on the lives of patients and their caregivers.”