Elicitation of utility scores in Canada for immune thrombocytopenia treated with romiplostim or watch and rescue

Abstract

Objectives:

The objective of this study was to obtain utilities, or preference-based quality-of-life values, from the Canadian general public, for potential health states experienced by immune thrombocytopenia (ITP) patients receiving either romiplostim (a new thrombopoietin mimetic agent) or ‘watch and rescue’ therapy. Utilities are needed to conduct a cost-utility analysis of romiplostim for formulary and reimbursement decisions.

Methods:

An electronic Time Trade-off (TTO) survey was developed and administered to a sample of the general public in Canada, with 12 distinct health states derived from two randomized clinical trials of romiplostim vs watch and rescue treatment. Two pilot tests assessed interpretability and respondent burden. In the final survey, each subject was administered the TTO for four randomly-selected health states. Descriptive statistics were computed for utility scores, and differences between health states were evaluated with an analysis of variance model.

Results:

Eight hundred and twenty-one adults completed the TTO survey. Mean age was 36.4 (SD = 15) years; 63% were female. Mean (SD) utility scores ranged from 0.476 (0.271) for the most severe health state (significant bleeding) to 0.633 (0.282) for the least severe health state depicting successful treatment with romiplostim. Statistical significance was found on the mean difference between the most severe health state and five other health states (p < 0.05). After adjusting utilities for matching Canadian demographic parameters, no substantial difference was found between original utility scores and adjusted scores.

Conclusions:

This study provides evidence of the Canadian general public’s preference for 12 ITP health states pertaining to romiplostim treatment or watch and rescue. This study had a number of limitations, the main ones being the lack of perfect match in demographics between this sample and the Canadian population, as well as the fact that the scenario descriptions were based on both published literature and expert opinion. Despite those limitations, the obtained utility scores may be used in cost-utility models of romiplostim as a treatment for ITP patients in Canada.

Keywords::

• ITP
• Romiplostim
• Utility
• Immune thrombocytopenia
• TTO
• Quality-of-life

Transparency

Declaration of funding

This study was sponsored by Amgen Inc. Thousand Oaks, CA, USA.

Declaration of financial/other interests

ATT has disclosed that he has been a consultant for Amgen and Novartis, and has received grant support from the Canadian Blood Services. DMA has disclosed that he has been a consultant for Amgen, and has received grants from Amgen, GSK, and Hoffman-LaRoche. JM has disclosed that he has no relevant financial relationships. MI has disclosed that he is an employee of PharmIdeas, a company that performed data collection and analysis under contract with Amgen. RD and JI have disclosed that they are employees of Amgen and own stock in the company.

Acknowledgments

The authors would like to acknowledge Olivier Desjardins (formerly of PharmIdeas) and Dr Amiram Gafni (of McMaster University) for their scientific input in the design of the study as well as Marlene Bakmazian, Farhana Khondoker, and Jade Berbari for facilitating data collection, Bechara Farah (all of PharmIdeas) for analyses, as well as Susan Mathias (of Health Outcomes Solutions) and Michelle Zakson (of Amgen Inc.) for writing support.

Notes

*eQtool is a registered trade mark of PharmIdeas USA Inc., a wholly owned subsidiary of PharmIdeas Research and Consulting Inc.