Treatment patterns and outcomes among adults with immune thrombocytopenia receiving pharmaceutical second-line therapies: a retrospective cohort study using administrative claims data

Abstract

Objectives

To describe and compare real-world treatment patterns and clinical outcomes among individuals with immune thrombocytopenia (ITP) receiving second-line therapies (rituximab, romiplostim, or eltrombopag).

Methods

A retrospective cohort study was conducted using a large administrative claims database (January 2013–May 2020) among continuously enrolled patients ≥18 years prescribed second-line ITP therapies. The index date was the date of the first claim of the study medications. Treatment patterns and outcomes were measured during the 12-month follow-up period. Inverse probability of treatment weighting (IPTW) was used to balance covariates across treatment groups. Multivariable logistic regression was used to compare treatment patterns and bleeding risk outcomes.

Results

A total of 695 patients were included (rituximab, N = 285; romiplostim, N = 212; eltrombopag, N = 198). After IPTW, all baseline covariates were balanced. Compared to eltrombopag, patients in the rituximab cohort were 57% more likely to receive other ITP therapies (systematic corticosteroids or third-line therapies) during the follow-up period (odds ratio [OR] = 1.571, p = .030). There was no significant difference in the odds of receiving a different second-line therapy or experiencing a bleeding-related episode among three groups (p > .050). Patients in the romiplostim cohort were 69% more likely to receive rescue therapy compared to those in the rituximab cohort (OR = 1.688, p = .025).

Conclusion

Patients with ITP receiving rituximab were more likely to need other ITP therapies but did not experience higher risk of bleeding compared to those receiving eltrombopag or romiplostim. Benefits, risks, cost-effectiveness, and patient preference should all be considered in optimizing second-line therapy for ITP.

Keywords:

• Immune thrombocytopenia
• retrospective claims analysis
• treatment pattern
• inverse probability of treatment weighting

Transparency

Declaration of funding

This study was partially funded by a Platelet Disorder Support Association (PDSA) Barbara and Peter T. Pruitt, Jr. ITP Research Award.

Declaration of financial/other relationships

Yi Liang has worked as a contractor for AbbVie, Inc. since April 2021 and has no relevant financial interests to disclose. Karen Rascati is a Professor Emeritus at the University of Texas College of Pharmacy and has no relevant financial interests to disclose. Jamie C. Barner is a Professor at the University of Texas College of Pharmacy and has no relevant financial interests to disclose. Kenneth A. Lawson is a Professor Emeritus at the University of Texas College of Pharmacy and has no relevant financial interests to disclose. Radhika Nair is Director of Medical Research Intercept Pharmaceuticals and has no relevant financial interests to disclose. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

Study conceptualization: Yi Liang, Karen Rascati; Study design: Yi Liang, Karen Rascati, Jamie C. Barner, Kenneth A. Lawson, Radhika Nair; Data analyses: Yi Liang; Interpretation of data and critical revision of the manuscript: Yi Liang, Karen Rascati, Jamie C. Barner, Kenneth A. Lawson, Radhika Nair. All authors have read and approved the final draft of the manuscript submitted.

Acknowledgements

The authors thank Jason Melear, MD and Athira Unnikrishnan, MD from Texas Oncology for providing advice and comments on this study. We also thank the Platelet Disorder Support Association (PDSA) for providing financial support for this study.