Projecting the Long-Term Economic Impact of Once-Monthly Paliperidone Palmitate Versus Oral Atypical Antipsychotics in Medicaid Patients with Schizophrenia

BACKGROUND: Recent evidence has demonstrated that, over 12 months, pharmacy costs associated with switching nonadherent recently relapsed patients from oral atypical antipsychotics (OAAs) to once-monthly paliperidone palmitate (PP1M) were offset by reduced relapse rates and schizophrenia-related health care costs. In addition, earlier use of PP1M may generate greater cost savings. OBJECTIVE: To project the long-term economic impact when a proportion of nonadherent patients with a recent relapse switch from OAAs to PP1M. METHODS: A 36-month decision-tree model with twelve 3-month cycles was developed from a Medicaid payer’s perspective. The target population was nonadherent, recently relapsed OAA patients. At equal adherence, probability of relapse was equal between PP1M and OAAs, and OAA patients were nonadherent until treatment switch. Event rates (adherence, relapse, and switch) and cost inputs (pharmacy and relapse) were based on the literature, and rates remained constant. Outcomes included number of relapses, pharmacy costs, and relapse costs (2017 U.S. dollars) at years 1, 2, and 3. One-way sensitivity (OSA) and probabilistic sensitivity analyses (PSA) evaluated the effect of varying model inputs on health plan and per-patient level costs. RESULTS: Based on a hypothetical health plan of 1 million members, 3,037 OAA patients were recently relapsed and nonadherent. Compared with continuing OAAs, switching 5% of patients (n = 152) to PP1M resulted in net cost savings of $674,975, $723,298, and $562,310 at the plan level; $4,445, $4,764, and $3,703 per patient switched per year; and $0.0562, $0.0603, and $0.0469 per member per month in years 1, 2, and 3, respectively, resulting in total plan-level savings of > $1.9 million over 3 years. A total of 221 relapses were avoided (year 1: 92; year 2: 72; and year 3: 57). In years 1, 2, and 3, respectively, total annual plan-level schizophrenia-related costs were $114.1 million, $107.2 million, and $105.8 million when all patients switched to PP1M before any subsequent relapse (n = 3,037); $123.4 million, $109.6 million, and $106.7 million when patients switched to PP1M after a first subsequent relapse (n = 2,631); and $127.6 million, $121.6 million, and $117.0 million when all patients remained on OAAs. The cost per patient switched to PP1M was lower when all patients received PP1M before a subsequent relapse versus after their first subsequent relapse at all years (year 1: $37,559 vs. $45,089; year 2: $35,288 vs. $36,321; and year 3: $34,826 vs. $35,155). OSA demonstrated consistent net cost savings per patient switched, ranging from $640 to $10,484 (year 1); $1,774 to $9,245 (year 2); and $1,354 to $7,026 (year 3). PSA demonstrated 96.3%, 99.7%, and 99.7% of iterations were cost saving in years 1, 2 and 3, respectively. CONCLUSIONS: Pharmacy costs associated with switching nonadherent OAA patients with a recent relapse to PP1M were offset by reduced relapse rates and health care costs at years 1, 2, and 3, with earlier use of PP1M resulting in increased cost savings at all years.