Cost-effectiveness analysis of paliperidone palmitate versus long-acting risperidone as maintenance treatment in schizophrenia patients in Italy

Objective To evaluate the cost-effectiveness of paliperidone palmitate (paliperidone long-acting injectable; PP) compared with long-acting injectable risperidone (RRP) in multi-episode patients (two or more relapses) with schizophrenia in Italy. Methods A pre-existing Markov model was utilized to simulate the history of a cohort of multi-episode patients transitioning through different health states on a monthly basis over a 12 or 24 month horizon from the perspective of the Italian National Health Service. Therapeutic strategies consisted of treatment with long-acting injectable risperidone (mean dose 37.5 mg every 2 weeks) or paliperidone palmitate (mean dose 75 mg equivalent [eq.] every month). Probability of relapse, level of adherence, side effects (extrapyramidal symptoms, tardive dyskinesia, weight gain and diabetes) and treatment discontinuation (switch) were derived from long-term observational data when feasible. The cost-effectiveness analysis considered quality adjusted life-years (QALYs) and direct medical costs. QALYs and costs (expressed in 2014 euro) were discounted at 3% annually. A one-way sensitivity analysis and a probabilistic sensitivity analysis were conducted. Results Paliperidone palmitate is the dominant long-acting injectable therapeutic option: a more effective (additional QALYs, less relapses) and less costly treatment option compared with long-acting injectable risperidone over a 12 or 24 month horizon. Results were robust when tested in sensitivity and probabilistic analyses. Conclusions Paliperidone palmitate was cost-saving from the Italian National Health Service perspective compared with long-acting injectable risperidone in the long-term treatment of multi-episode (two or more relapses) schizophrenia patients.