OBJECTIVES: To assess lifetime cost-effectiveness of glatiramer acetate (GA) compared to natalizumab (NZ) in patients diagnosed with relapsing-remitting multiple sclerosis (RRMS) in the presence of long-term clinical evidence.
METHODS: A literature-based Markov model was developed with patients transitioning through health-states based on Kurtzke expanded disability status scale (EDSS). Patients in the model are 21 years of age with RRMS and start in any of the health-states at diagnosis. Patients with an EDSS score below 6.0 receive treatment. Treatment effects for relapse and disease progression were obtained from clinical trials and long-term clinical evidence where available. Transition rates were estimated by applying a percent reduction of treatment effects of therapies to natural history rates of relapse and disease progression. Rates were adjusted for treatment discontinuation and persistent NZ antibodies. Patients incurred drug, other medical and lost worker productivity costs. Patients on NZ incurred additional costs for monitoring, diagnosis, and treatment of progressive multifocal leukoencephalopathy (PML), a possible serious adverse event for patients on NZ. Utility weights for each health-state were taken from published utility assessments for people with RRMS. The primary outcomes of the model were lifetime costs and quality-adjusted life years (QALYs). Costs (2005US$) and outcomes were discounted at 3% annually.
RESULTS: The lifetime costs per patient for GA were $352,762 and for NZ were $422,210. QALYs during the lifetime of a patient on GA were 9.303 and 9.300 for a patient on NZ. The incremental cost per QALY for patients on GA and NZ compared to symptomatic treatment alone was $258,464 and $580,119 respectively. GA is cost-saving when compared to NZ. PML had very little impact on results.
CONCLUSION: While incorporating all the long-term clinical evidence, model results indicated that GA was both less costly and more effective over a patient’s lifetime than NZ in treating RRMS.
