INTRODUCTION: Chronic myeloid leukemia (CML) is a bone marrow and blood disorder accounting for 15% of adult leukemia. Tyrosine kinase inhibitors (TKIs) have been the standard of care for CML treatment. However, an association between TKI use and cardiovascular events has been observed. Ponatinib and bosutinib are introduced to provide more options for patients who failed their first-line treatment. The incidence of major adverse cardiac events (MACEs), arterial occlusive events (AOEs), and venous occlusive events (VOEs) were assessed among CML patients who were prescribed ponatinib vs bosutinib.

METHODS: A retrospective observational study was conducted among adult CML patients aged ≥18 years with use of 1 or 2 prior TKIs who were prescribed bosutinib or ponatinib. Study patients were selected from the IBM® MarketScan® Research database from July 2012-June 2017. The index date was defined as the index drug prescription date, identified based on TKI use during the identification period (January 2013-December 2016) in a hierarchical order based on the sequence of treatment lines: ponatinib and bosutinib without ponatinib. Continuous health plan enrollment for ≥6 months pre-index date (baseline period) and at least 6 months post-index date (follow-up period) was required. Cardiovascular (CV) events (MACEs, AOEs, VOEs) using ICD-9/10-CM diagnosis codes occurring through the earliest of index TKI discontinuation, switch to another TKI, or end of follow-up period, were calculated as the number of events per 100 person-years (PYs). Inverse probability of treatment weighting (IPTW) was applied to adjust for differences in baseline characteristics between the treatment cohorts. Kaplan-Meier (KM) and Cox proportional hazard model analyses were conducted on the adjusted sample to examine any difference in CV event risk.

RESULTS: After applying the selection criteria, 79 and 109 patients were included in the ponatinib and bosutinib cohorts, respectively. Mean ages were 53 years (ponatinib cohort) and 58 years (bosutinib cohort). The average Charlson Comorbidity Index (CCI) scores - defined by categorizing comorbidities using diagnosis codes - were 1.23 for ponatinib and 1.81 for the bosutinib cohort. Common baseline comorbid conditions included anemia (ponatinib: 49%; bosutinib 34%), hypertension (ponatinib: 33%, bosutinib: 46%), and diabetes (ponatinib: 15%; bosutinib: 29%). Some patients were observed to have CV events, specifically MACEs (ponatinib 8%; bosutinib 16%) and AOEs (ponatinib 15%; bosutinib 28%), before index ponatinib or bosutinib use. In the follow-up period, ponatinib patients were associated with a similar incidence of MACEs (14.70 vs 10.46 per 100 PYs; p=0.464), AOEs (29.56 vs 34.50 per 100 PYs; p=0.632), and VOEs (36.21 vs 34.70 per 100 PYs; p=0.890) compared to bosutinib patients. After applying IPTW, similar risks of the CV events (MACE, AOEs, VTEs) were observed in the KM analysis (Figure 1) expressed as time to CV event. After adjusting for additional confounders using Cox models, compared to those with bosutinib use, ponatinib patients were associated with similar rate of MACEs (Hazard Ratio [HR]: 1.02; 95% CI: 0.34, 3.01), AOEs (HR: 0.90; 95% CI: 0.43, 1.85), and VOEs (HR: 0.92; 95% CI: 0.44, 1.94).

CONCLUSION: Among CML patients treated with ponatinib or bosutinib in second or third line, similar risks of cardiovascular events (MACE, AOEs, VTEs) were observed in the follow-up in this study in a community setting.

Figure 1
Figure 1
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Disclosures

Levy:Takeda (Millennium Pharmaceuticals): Consultancy. Xie:STATinMED Research: Other: I am a paid employee of STATinMED Research which is a paid consultant to Takeda Pharmaceutical Corporation. . Wang:STATinMED Research: Other: I am a paid employee of STATinMED Research which is a paid consultant to Takeda Pharmaceutical Company. . Neumann:Millennium Pharmaceuticals (Takeda): Employment, Other: I am a paid employee of Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Ltd. Srivastava:Millennium Pharmaceuticals (Takeda): Other: I am a paid employee of Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Ltd. Naranjo:Millennium Pharmaceuticals (Takeda): Other: I am a paid employee of Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Ltd. Xu:Millennium Pharmaceuticals (Takeda): Other: I am a paid employee of Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Ltd. Zhang:STATinMED Research: Other: I am a paid employee of STATinMED Research which is a paid consultant to Takeda Pharmaceutical Corporation.. Dalal:Millennium Pharmaceuticals (Takeda): Other: I am a paid employee of Millennium Pharmaceuticals, Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Ltd.

Topics:
bosutinib, leukemia, myelocytic, chronic, ponatinib, protein-tyrosine kinase inhibitor, cardiovascular event, follow-up, anemia, cardiac event, diabetes mellitus, diabetes mellitus, type 2

Author notes

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Asterisk with author names denotes non-ASH members.

© 2019 by The American Society of Hematology
2019
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