Budget impact of introducing once-every-6-months paliperidone palmitate in US health care plans

BACKGROUND: In the United States, most patients with schizophrenia have Medicaid coverage. Antipsychotic treatments are the cornerstone of schizophrenia management; most patients are treated with daily oral antipsychotics but struggle with medication adherence. Evidence suggests that medication adherence is inversely correlated with dosing frequency. Once-monthly paliperidone palmitate (PP) has been demonstrated to improve adherence compared with oral antipsychotics; transitioning to once-every-3-months PP (PP3M) further improved adherence. In 2021, once-every-6-months PP (PP6M) was approved by the US Food and Drug Administration to provide even longer between-dose intervals. Public health stakeholders who aim to improve medication adherence are interested in understanding how introducing PP6M to the formulary will impact the budget. OBJECTIVE: To evaluate the budget impact of introducing PP6M to the formulary from the perspectives of a hypothetical US multistate health care payer and state Medicaid programs using California, Georgia, and Ohio as examples. METHODS: The budget impact model was developed from a payer perspective, comparing the reference scenario (without PP6M in the market) with a new scenario (with PP6M). The study population included patients with schizophrenia who were eligible to receive PP6M. Market shares were assigned to the reference and new market scenarios. Efficacy was measured by the relative risk of relapse while receiving treatment. Adherence effects were included in the model and affected costs of treatment and relapse rates. A deterministic 1-way sensitivity analysis was performed. RESULTS: Base-case results for a multistate payer with 1 million members demonstrate that adding PP6M to the market results in total incremental plan-level costs ranging from $7,747 in year 1 to $11,501 in year 5. Increased drug costs were offset by administration and relapse cost savings ($105 and $881 in year 5, respectively). The average incremental cost per treated patient per year was stable at $180.06 for each year, and the incremental cost per member per month stayed below $0.01 for each year. The results of the model from the state-level Medicaid scenarios are broadly similar to those of the multistate base-case perspective. The 1-way sensitivity analysis demonstrated the model is most sensitive to the per-package costs of PP6M and PP3M, along with the proportion of patients fully adherent with PP3M. CONCLUSIONS: The budget impact of introducing PP6M as a treatment option is minimal. With the expected cost offsets from reduced administration and relapse costs due to adherence benefits, these results suggest that PP6M can be a viable treatment option from a clinical and a budgetary perspective.