Agitation is one of the most common symptoms of Alzheimer’s disease, leading patients to become restless or even verbally and physically aggressive. The FDA has approved the first drug to treat these behavioral symptoms.
The Thursday approval of the drug, brexpiprazole (brand name Rexulti), covers the treatment of agitation associated with dementia due to Alzheimer’s. The regulatory decision is an expanded approval for the product, marketed by partners Otsuka Pharmaceutical and Lundbeck. The drug is already used to treat schizophrenia and depression. Last month, an independent FDA advisory committee backed the drug, voting 9-1 that the companies had provided enough data to allow the identification of Alzheimer’s patients with agitation in whom the therapy’s benefits outweigh its risks.
Rexulti is a small molecule formulated as a once-daily pill. The way the drug works in any of its approved indications is not known. But the drug is thought to have an effect on serotonin receptors, receptors found in the central and peripheral nervous systems that play a role in regulating mood and anxiety.
Approval of Rexulti for treating agitation in Alzheimer’s patients is based on the results of two placebo-controlled Phase 3 studies enrolling participants ranging from 51 to 90 years of age. Each 12-week study tested two different doses. The main goal was to measure the change in score according to an assessment that uses input from caregivers to rate the frequency of agitative behaviors. The FDA said results from both studies showed statistically significant and clinically meaningful improvements in treated patients compared to those given a placebo.
The most common side effects reported from these clinical trials included headache, dizziness, urinary tract infection, cold symptoms, and sleep disturbances—both drowsiness and insomnia. The drug retains the black box warning on its label cautioning physicians and patients that treatment with antipsychotic drugs carries an increased risk of death. The warning also says Rexulti is not approved for treating those with dementia-related psychosis without agitation.
Rexulti is available in six doses. For the agitation in Alzheimer’s indication, the recommended starting dose is 0.5 mg taken once daily for the first seven days. For the next seven days, the dose increases to 1 mg once daily. On day 15, the dose increases to 2 mg, which is the recommended target dose. The FDA said the dosage can be increased to the maximum recommended daily dose of 3 mg after at least 14 days, based on the patient’s response to the drug and tolerance of its effects. The drug is not to be used as an “as needed” treatment for agitation.
A Deep-dive Into Specialty Pharma
A specialty drug is a class of prescription medications used to treat complex, chronic or rare medical conditions. Although this classification was originally intended to define the treatment of rare, also termed “orphan” diseases, affecting fewer than 200,000 people in the US, more recently, specialty drugs have emerged as the cornerstone of treatment for chronic and complex diseases such as cancer, autoimmune conditions, diabetes, hepatitis C, and HIV/AIDS.
Rexulti was discovered by Tokyo-based Otsuka and co-developed with Lundbeck. In 2015, the FDA approved the pill as an adjunct to antidepressants for treating major depressive disorder as well as for treating schizophrenia. In 2016, the agency updated the drug’s label to include maintenance treatment of schizophrenia.
Lundbeck, based in Copenhagen, Denmark, reported 3.9 billion Danish krone (about $570 million) in 2022 sales for Rexulti, a 37% increase over sales in the prior year. In Lundbeck’s 2022 annual report, the company said the drug is its largest U.S. product and patient data suggest that more than 75% of the prescriptions are for major depressive disorder. Lundbeck has high hopes for Rexulti in its newest approved indication.
“We expect in 2023 and 2024 there will be targeted investment behind the potential blockbuster opportunity for brexpiprazole for the treatment of agitation associated with Alzheimer’s dementia,” Lundbeck said in the report. “Based on organic growth, we expect revenue to show a mid-single digit compound annual growth rate (CAGR) over the mid-term period (3-4 years).”
Photo: Matthew Horwood, Getty Images
