U.S. regulators have approved the first drug for treating a neurological syndrome that causes uncontrollable body movements that can also interfere with speech, swallowing and breathing.
The sometimes-disabling disorder, tardive dyskinesia, is caused by some widely used prescription medicines for psychiatric and gastrointestinal disorders. It can surface while patients are on those medicines or years after they stop. It affects about 500,000 U.S. patients.
The Food and Drug Administration on Tuesday approved Ingrezza, developed by Neurocrine Biosciences, for treating adult patients. The San Diego-based biotech company didn’t disclose the drug’s list price, but said it will when it begins offering the once-a-day capsule for sale in May.
A second drug for the disorder, from Israel’s Teva Pharmaceuticals, is expected to win FDA approval in late August.
Tardive dyskinesia causes repetitive, involuntary movements, including rapid eye blinking, grimacing, lip-smacking and rapid movements of the trunk, arms and legs. It can be embarrassing for patients and lead to social withdrawal and job loss.
The condition usually occurs after long-term use of drugs that block important receptors in the brain that help regulate movement and motor function.
Those drugs include newer pills for schizophrenia and related psychiatric disorders that were touted as safer than older antipsychotic drugs, a claim that led to them being widely prescribed for depression, bipolar disorder and other conditions.
Patients taking certain drugs for acid reflux and other stomach disorders, such as metoclopramide, also have developed tardive dyskinesia.
Until now, treatment generally was limited to stopping or reducing the dosage of the psychiatric or stomach medication, or switching to a different medication. However, stopping the original medication doesn’t halt tardive dyskinesia in most patients, and doing so can destabilize schizophrenia patients, according to Neurocrine’s chief executive, Kevin Gorman.
Ingrezza, known chemically as valbenazine, was tested on more than 1,000 patients. In the final stage of testing, 40 percent of patients given a high dose of Ingrezza saw their movement symptoms decrease by at least half after six weeks, compared to about 19 percent of those getting dummy capsules, Neurocrine reported.
Gorman said study participants who kept taking it after the six weeks had additional improvement and after a year, a small percentage who stopped taking Ingrezza then found their tardive dyskinesia symptoms didn’t return.
Ingrezza’s possible side effects were rare and include fatigue, restlessness, dry mouth, headaches and joint pain.
The drug is also being tested in patients as a possible treatment for Tourette’s syndrome.