Rexulti Eases Motor and Psychiatric Symptoms of Huntington’s, Case Report Shows

Rexulti (brexpiprazole), an antipsychotic medicine approved for schizophrenia and in some cases depression, eases motor and psychiatric symptoms of Huntington’s disease, according to a case study.

The study, “Effectiveness of Brexpiprazole in the Treatment in a Patient with Huntington’s Disease,” was published in the journal Psychiatry and Clinical Neurosciences.

Huntington’s disease is a neurodegenerative disorder characterized by uncontrolled jerking and writhing movements known as chorea, loss of cognitive ability, and psychiatric problems. Motor symptoms include difficulty walking and maintaining balance.

Researchers in Japan described the case of a Huntington’s patient whose choreic movements and psychiatric symptoms were successfully resolved with Rexulti, a medication approved in the U.S. to treat schizophrenia and, as an add-on therapy, major depressive disorder.

“To the best of our knowledge, this is the first case report of treatment of an HD patient with brexpiprazole,” the researchers wrote.

The 41-year-old man was admitted to a hospital’s neuropsychiatric unit due to impulsive and aggressive behavior.

Genetic testing confirmed the diagnosis of Huntington’s; the patient had 56 CAG repeats within the HTT gene sequence, surpassing the 35 normally seen in healthy individuals. (Huntington’s is caused by a mutation in the huntingtin, or HTT, gene that leads to excessive repeats of a DNA segment known as CAG.)

The man also had a seven-year history of chorea and cognitive decline.

He was unable to walk without assistance, and he came to the hospital with “abrupt, irregular, and unpredictable movements of his limbs and torso, along with a darting tongue,” according to the report. He also had psychiatric symptoms, including suicidal intention, anxiety and aggression.

Clinicians decided not to treat him with Xenazine (tetrabenazine), a medication specifically approved to treat chorea associated with Huntington’s, because it can worsen psychiatric symptoms.

They also excluded the antipsychotics Zyprexa (olanzapine) and Abilify (aripiprazole) because the patient had aspiration pneumonia — a pulmonary infection that develops when stomach contents reach the lungs — and rhabdomyolysis, in which damaged muscle tissue is destroyed and toxic substances build up in the bloodstream. Both conditions might be made worse by those medications.

The doctors opted for Rexulti, giving the patient 1 milligram per day at first and 2 mg/day after two weeks. The treatment led to marked improvements in his motor function and lessened his psychiatric symptoms, without any obvious side effects.

His mobility and balance were evaluated using the Unified Huntington’s Disease Rating Scale (UHDRS), a scale that ranges from zero (no motor impairments) to 128 (severe motor impairments). His motor score was 38 after six weeks of treatment with Rexulti, down from 61 at admission. He  also showed improvements in gait and on the retropulsion pull test, which assesses a person’s ability to recover from a sudden shoulder pull.

“His gait became so smooth and stable that he was able to climb up stairs without assistance in the ward,” the clinicians wrote.

His score on the Functional Independence Measure, which measures physical disability from 18 (worst) to 126 (best), rose to 111 from 97. Psychomotor aggression, agitation, and suicidal behaviors were resolved completely, the doctors said. After eight weeks of treatment with Rexulti, he was discharged from the hospital.

“This case suggests that [Rexulti] may be clinically useful treatment option for HD,” the physicians said. “However, we should emphasize that this is just a single case report. Further clinical trials are warranted to endorse the findings.”