Antipsychotic Treatment Pathways, Real-World Adherence, Healthcare Resource Utilization, and Healthcare Costs Among Patients With Schizophrenia Treated With Once-Monthly, Once-Every-Three-Months, and Once-Every-Six-Months Paliperidone Palmitate in the United States.

PURPOSE: Patients with schizophrenia can initiate once-every-6-months paliperidone palmitate (PP6M), currently the longest dosing interval long-acting injectable (LAI) antipsychotic (AP), following adequate treatment with once-every-3-months paliperidone palmitate (PP3M) or once-monthly paliperidone palmitate (PP1M). However, limited real-world evidence exists describing the AP treatment pathways, adherence, healthcare resource utilization, and costs among patients with schizophrenia treated with PP1M, PP3M, or PP6M.

METHODS

Descriptive retrospective analysis of 3 cohorts of adults with schizophrenia who had ≥4 PP1M, ≥1 PP3M, or ≥1 PP6M claim(s) were selected from Komodo Research Data closed US insurance claims (January 01, 2016 to December 31, 2023; index date: first PP1M/PP3M/PP6M claim on/after January 09, 2021). Patients included had ≥12 months of pre-index insurance eligibility and no bipolar/pregnancy diagnoses. AP treatment pathways were evaluated over the pre-index continuous insurance eligibility period. The 6- and 12-month adherence to the index treatment (proportion of days covered ≥80%), schizophrenia-related inpatient admissions, and direct all-cause costs (2023 US dollars; per-patient-per-year [PPPY]) were described from index to the earliest of end of data or eligibility.

FINDINGS: The sample included 17,463 patients in the PP1M cohort, 5348 in the PP3M cohort, and 628 in the PP6M cohort, with mean follow-up of 16.0, 14.2, and 9.4 months, respectively (mean age 40.6-41.3 years; 24.8-28.2% females). Patients were observed for 4.6 years on average before initiating PP6M, during which 72.1% used oral APs, 83.3% used PP1M (average of 21.9 months), and 71.0% used PP3M (average of 27.8 months); 98.6% of patients transitioned to PP6M directly from PP1M (32.5%) or PP3M (67.5%). Two-thirds of patients (PP1M: 61.2%; PP3M: 64.6%) initiated PP6M at the higher dose strength of 1560 mg. Among patients in the PP1M, PP3M, and PP6M cohorts with sufficient follow-up, 59.4%, 75.8%, and 100% were adherent at 6 months and 51.4%, 59.1%, and 73.9% were adherent at 12 months. At 3 months post index, 5.1% of the PP1M cohort, 2.1% of the PP3M cohort, and 1.8% of the PP6M cohort had a schizophrenia-related inpatient admission. Mean all-cause medical costs PPPY numerically decreased with less frequent administration (PP1M: $22,116; PP3M: $16,030; PP6M: $14,217); PP6M had the lowest medical to total all-cause cost ratio (PP6M: 26.7%; PP3M: 35.5%; PP1M: 44.9%).

IMPLICATIONS: Patients with schizophrenia using PP3M or PP6M were numerically more adherent to treatment, incurred lower medical costs, and a lower proportion had a schizophrenia-related inpatient admission relative to patients using PP1M, suggesting LAIs with longer dosing intervals may improve clinical outcomes and decrease economic burden.