Background: Bipolar disorder is a severe recurrent, episodic psychiatric condition with a worldwide prevalence of approximately 1%, affecting more than 5 million adults in the United States in 2020. A subtype, bipolar I disorder (BP-I), which accounts for approximately one-quarter of cases, is associated with impairments in psychosocial functioning and quality of life. Recommended treatment options include daily oral, or long-acting injectable, antipsychotics, including the aripiprazole once every month formulation, which has been shown to improve adherence compared with oral treatments. A new formulation of aripiprazole for administration once every 2 months ready to use (Ari 2MRTU) has been shown to have similar efficacy to monthly treatment, with only 6 doses annually.
Objective: To estimate the financial impact of introducing the new formulation of aripiprazole as a treatment option for adults diagnosed with BP-I in the United States.
Methods: A cohort of eligible patients with BP-I was selected from a hypothetical US health plan of 1 million members, and the treatment costs modeled with a 3-year time horizon, in scenarios with or without the addition of Ari 2MRTU. Inputs into the model included user-definable estimates of the current and projected market share of the available antipsychotics, forecast uptake of aripiprazole new formulation, acquisition, initiation, and administration costs, hospitalization costs, time on treatment, and patient adherence. The budget impact was estimated as the difference in the annual cost for the total cohort for the current and new scenarios, the cost per member per month, and the cost per treated member per month. Deterministic sensitivity analyses were also conducted to examine the extent to which the model results were affected by variations in individual input parameters.
Results: The total budget impact of introducing a formulation of Ari 2MRTU as maintenance monotherapy for treating a cohort of eligible patients with BP-I in the United States from a health plan of 1 million members was estimated to be $898,930 over 3 years, representing a per member per month cost saving of $0.025 and a per treated member per month cost saving of $2.43. The sensitivity analysis supports a modest reduction in budget, with the main driver being adherence with medication regimen.
Conclusions: The introduction of Ari 2MRTU as a maintenance treatment for adults with BP-I is expected to have a neutral effect on payer budgets in the United States and is a potentially favorable option for patients who prefer less frequent dosing.