Valbenazine granted breakthrough drug status for treating tardive dyskinesia.

The chronic use and high dosing of typical neuroleptics or centrally acting dopamine receptor blocking antiemetics predispose patients to the onset of tardive syndromes. One particular subtype, tardive dyskinesia, is characterized by rapid, repetitive, stereotypic, involuntary movements of the face, limbs or trunk. The inhibition of the vesicular monoamine transporter system, using tetrabenazine therapy, improves the severity of tardive dyskinesia. But there are also drawbacks to tetrabenazine treatment, such as a fluctuating response and the need for frequent intake due to its rapid metabolism. Clinical research on the potentially more efficacious and easier to use tetrabenazine analogs is already under way. One of them is valbenazine, the purified parent drug of the (+)-α-isomer of tetrabenazine. The FDA lowered approval hurdles for valbenazine due to a successful Phase II trial, which showed a distinctive improvement in tardive dyskinesia symptoms during valbenazine administration. This resurgence in the clinical research of tardive syndrome therapy is most welcome. This author notes that the putative long-term side effects of valbenazine should carefully be investigated in the future via naturalistic observational trials. Furthermore, valbenazine may also support the onset of symptoms, such as Parkinsonism and depression, with chronic administration, as it, to a certain extent, shares the mode of action of tetrabenazine.