Cost-effectiveness of olanzapine in the first-line treatment of schizophrenia in China

Abstract

Objectives: This study aimed to analyze (1) the cost-effectiveness of olanzapine orally disintegrating tablet (ODT) compared to olanzapine standard oral tablet (SOT) and (2) the cost-effectiveness of olanzapine-SOT compared to aripiprazole-SOT for patients with schizophrenia in China.

Methods: A microsimulation model was adapted from a healthcare payers’ perspective. The model ran over a 1-year time horizon, using quarterly cycles. The costs of adverse events were acquired through a clinical expert panel. The average bidding prices in China of olanzapine-ODT, olanzapine-SOT, aripiprazole-SOT, and other switch alternatives were used. Inpatient and outpatient medical costs were sourced from the Urban Employee Basic Medical Insurance database in Tianjin. Additionally, adherence, efficacy, safety, and utility data were taken from the literature. Uncertainty of parameters were assessed through one-way and probabilistic sensitivity analyses.

Results: The total annual costs per patient in aripiprazole-SOT arm, olanzapine-SOT arm, and olanzapine-ODT arm are USD 2,296.05, USD 1,940.05, and USD 2,292.81, respectively. The average number of relapses per patient in 1 year in the aripiprazole-SOT arm, olanzapine-SOT arm, and olanzapine-ODT arm, are 0.734, 0.325, and 0.198, respectively. The quality-adjusted life years (QALYs) gained per patient in 1 year in the aripiprazole-SOT arm, olanzapine-SOT arm, and olanzapine-ODT arm are 0.714, 0.737, and 0.758, respectively. Consequently, (1) the incremental cost-effectiveness ratios (ICERs) of administrating olanzapine-ODT over olanzapine-SOT are USD 2,791.96 per relapse avoided and USD 16,798.39 per QALY gained; and (2) the ICERs of using olanzapine-SOT over aripiprazole-SOT are USD –870.39 per relapse avoided and USD –15,477.93 per QALY gained. All ICERs are under the willingness-to-pay threshold in China of USD 25,772.67. The sensitivity analyses confirmed the robustness of the results.

Conclusion: As the first-line treatment for schizophrenia in China, olanzapine-ODT is cost-effective compared to olanzapine-SOT and olanzapine-SOT is cost-effective compared to aripiprazole-SOT.

Keywords:

• antipsychotics
• cost-effectiveness
• orally disintegrating
• olanzapine
• schizophrenia

JEL classification codes:

• I18
• I19

Transparency

Declaration of funding

This study was funded by Eli Lilly and Company.

Declaration of financial/other interests

No potential conflict of interest was reported by the authors. YZ and YC are full-time employees of Eli Lilly and Company. The authors have no other relevant financial or other relationships to disclose. One peer reviewer on this manuscript discloses receiving manuscript or speaker’s fees from Astellas, Dainippon Sumitomo Pharma, Eli Lilly, Elsevier Japan, Janssen Pharmaceuticals, Meiji Seika Pharma, Novartis, Otsuka Pharmaceutical, Wiley Japan, and Yoshitomi Yakuhin and research grants from Eisai, Mochida Pharmaceutical, and Meiji Seika Pharma. Another peer reviewer discloses employment at the pharmaceutical company Lundbeck, LLC, which markets a long-acting injectable formulation of aripiprazole, one of the antipsychotic drugs described in the manuscript. The remaining peer reviewers on this manuscript have no other relevant financial or other relationships to disclose.

Acknowledgements

The authors thank Lee J. Smolen and Timothy M. Klein from Medical Decision Modeling Inc. (MDM) for the technique help for the probabilistic sensitivity analysis. The authors also thank Henry Hu for helping with the English language and proofreading the article.