According to an article published by MD Magazine, valbenazine, a VMAT2 inhibitor, has proven to be effective in treating patients with Tardive Dyskinesia (TD).
Before valbenazine’s FDA approval last year, treatment for Tardive Dyskinesia was limited to a drug cocktail of mild effectiveness.
What is Tardive Dyskinesia?
Tardive Dyskinesia is a serious neurological condition that can occur in people regularly taking anti-psychotic drugs. It causes repetitive, involuntary movements like twitching or grimacing.
Anti-psychotics all work in roughly the same way, by blocking D2 receptors, a subtype of dopamine receptor in the brain. A hypersensitivity to dopamine can result from prolonged blockages of these D2 receptors, which can cause additional neurological damage.
In order to best safeguard against these risks, it is common practice to prescribe anti-psychotics than would act on no more than three-fourths of a patient’s D2 receptors.
Valbenazine Proves Effective
Valbenazine is a VMAT2 inhibitor derived from tetrabenazine. It was approved for use by the FDA back in April 2017.
Unlike anti-psychotics that work by blocking dopamine receptors, VMAT2 inhibitors are designed to work by decreasing the amount of dopamine transmitted the receptor in the first place. It’s like changing the flow of a river by draining its source, rather than simply damming it.
In a six month long randomized double-blind trial (named KINECT-3), clinical researchers found statistically significant evidence that a daily 80mg dose of valbenazine could be effective in treating patients with Tardive Dyskinesia. They found that respondents taking the 80mg dose of valbenazine had a mean Abnormal Involuntary Movement Scale score 3.1 units better than that of the control group, whose score remained essentially unchanged since the start of the trial.
It also seemed that valbenazine presented little risk to patients it was prescribed to, with only slight increases (all under 2%) in reported cases of drowsiness, restlessness, or dry mouth. Patients in the control group even expressed suicidal ideation at a rate of 5.3%, over twice the number reported by the group taking valbenazine.
It seemed the trial had uncovered a real winner.
What’s Next for the Drug?
In a 2018 presentation in Hong Kong, a number of respondents from the KINECT-3 and later subsequent KINECT-4 trial (which was open label) reported their satisfaction with valbenazine.
Additional clinical trials are currently underway to determine if there are associated risks of dependency or withdrawal. They are expected to be completed by April of next year.
