Intramuscular treatment with Xeomin (incobotulinumtoxinA) decreases tremor severity and improves hand function in patients with essential tremor of the upper limbs, according to Phase 2 trial results.
Results of the trial, titled “Efficacy and safety of incobotulinumtoxinA for upper-limb essential tremor in a randomised, double-blind, placebo-controlled trial using kinematics-guided clinical decision support,” was presented at the recent 2018 World Congress on Parkinson’s Disease and Related Disorders in Lyon, France.
Essential tremor — often misdiagnosed as Parkinson’s disease — is a progressive movement disorder, found in more people ages 40 and older. It mainly affects the hands and arms, but head, voice, and leg tremors may also occur.
Unlike Parkinson’s, which is associated with motor symptoms such as slow movement and muscle stiffness, essential tremor does not cause other health problems, although unsteady gait may be observed. Also, while patients with Parkinson’s typically experience tremors when their hands are at rest, those with essential tremor have them when using their hands.
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Researchers conducted a randomized, double-blind Phase 2 clinical trial (NCT02207946) — sponsored by Merz Pharma, Xeomin’s developer — to evaluate the effectiveness and safety of a single, kinematics (motion)-guided intramuscular injection of Xeomin in adults with moderate to marked essential tremor in their upper limbs. The trial was conducted in the U.S. and Canada.
A total of 30 patients were included — 19 of whom were randomized to receive Xeomin, at a total dose of up to 195 Units, and 11 received a placebo. The participants all got an injection in the wrist, with optional injections into the shoulder and/or elbow. Muscle selection was based on each patient’s patterns of tremor, while doses per muscle were based on a kinematics-guided TremorTek analysis, which uses a combination of wearable movement sensors and computer software.
Differences between Xeomin and placebo were assessed at weeks four and eight for maximum wrist-tremor amplitude and motor performance, measured by the Fahn-Tolosa-Marin (FTM) Part B score. Analyses of tremor severity, with the FTM tremor scale, and grip strength were conducted over 24 weeks.
Treatment with Xeomin induced a trend toward decreased wrist-tremor amplitude, compared with placebo, at week four, and showed a significant improvement at week eight. Persistent anti-tremor effects were seen by motion measurements up to 24 weeks after a single injection of Xeomin.
The data further demonstrated that Xeomin significantly improved motor performance at both the fourth and eighth weeks. Maximum grip strength in the treated arm decreased by 20%, with no notable change in those on placebo. Although two patients receiving Xeomin reported localized finger-muscle weakness, none of the participants discontinued treatment due to muscle weakness.
“Kinematics-guided incobotulinumtoxinA (Xeomin) administration significantly decreased tremor severity and improved hand motor function versus placebo in patients with ET of the upper limb,” the researchers wrote.
Xeomin was recently approved by the U.S. Food and Drug Administration to treat adults with chronic sialorrhea, or excessive drooling, a common condition in Parkinson’s patients. It has also been approved for the treatment of adults with abnormal head position and neck pain due to involuntary contraction of neck muscles, abnormal spasm of the eyelids (blepharospasm) in patients previously treated with Botox (onabotulinumtoxinA), and to reduce muscle stiffness of the upper limbs.