COMPARING HEALTH-RELATED QUALITY OF LIFE OF SCHIZOPHRENIC PATIENTS WITH PREDOMINANT NEGATIVE SYMPTOMS TREATED WITH CARIPRAZINE AND RISPERIDONE

OBJECTIVES: Our study aimed at assessing the health-related quality of life gain with the drug cariprazine in the treatment of schizophrenia for patients with predominant negative symptoms (PNS) compared to risperidone. METHODS: We conducted a data analysis on individual patient level data derived from the RGH-188-005 clinical trial. The 30 items of the Positive and Negative Syndrome Scale (PANSS) were used to categorize patients into 8 different health states denned according to the approach of Mohr and Lenert published in 2004 and 2005. Utilities were assigned to Mohr-Lenert health states in accordance with the 2004 publication by Lenert et al. A Bayesian polytomous state transition model with an uninformative prior was constructed with the software WinBUGS with the involvement of three psychiatrists. This was linked to a Markov model with 8 health states based on the 8 Mohr-Lenert health states to estimate the potential gains in quality-adjusted life years (QALYs) of patients. Therapy switch as an option was built into the model, linked to lack of efficacy and adverse events to reflect real-life treatment patterns. RESULTS: Based on the transition relative frequency matrices, patients had a higher probability of reaching better health states on the cariprazine arm of the RGH-188-005 clinical trial compared to the risperidone arm. In the Markov model, this resulted in an estimated QALY gain of 0.02922 per patient when therapy switch was not considered, comparing cariprazine to risperidone after one year of treatment. The model showed an estimated QALY gain of 0.02530 per patient when therapy switch was considered, comparing cariprazine to risperidone after one year of treatment. CONCLUSIONS: Cariprazine can provide additional health-related quality of life gain in the treatment of schizophrenia for patients with predominant negative symptoms compared to risperidone.