Impact of race on the utilization and efficacy of CDK4/6i: Result from a real world database.

Abstract

e13036 Background: The combination of the CDK4/6 inhibitors(CDK4/6i) and endocrine therapy has improved overall survival(OS) in patients(pts) with endocrine sensitive or resistant disease. Only 43 pts of black race were included in the first line trials making interpretation of results in this group difficult. The goal of this retrospective analysis of a real world database was to look at the clinical utilization and prognostic impact of CDK4/6i among pts of white and black race who have hormone receptor positive (HR+ve)/HER2-ve metastatic breast cancer(MBC). Methods: For this analysis, we utilized a federated network of de-identified health data representing approximately 64 million pt lives available through the TriNetX Platform. We identified 5400pts with information on race who had HR+ve/HER2-ve MBC diagnosed between 2015 and 2020. OS was computed using the Kaplan Meier product limit method. Propensity score matching was performed on all comparisons of survival, matching patients from two cohorts on secondary malignancy location (as noted in ICD-10 diagnosis coding)and age group. Results: 4182 white pts and 1199 black pts were identified, and 1,194 pts in each group remained after matching. Mean age at diagnosis was 57.2 and 58.3 yrs among white and black pts respectively. OS among pts of white and black race was significantly different (HR 1.4, 95%CI 1.12-1.70, p < 0.0001), and 2-yr OS was 87.8% and 82.6% respectively. 599(20%) pts of white race and 148(18%) pts of black race received CDK4/6i therapy. The rate of uptake of use CDK4/6i was initially similar in 2015 however by 2020 some differences were observed with rate of uptake being 190 per 1000 and 264 per 1000 among pts of black and white race respectively. Pts of each race appeared to have a similar prevalence of CDK4/6i per line of treatment. OS among pts who received CDK4/6i and were of white and black race was not significantly different(HR 0.94, 95% CI 0.65- 1.38, p = 0.80), and 2-year OS was 69.9% and 69.5% respectively. Conclusions: Overall the proportional use of CDK4/6i was similar among pts of black and white and race. Although initial uptake appears to have been consistent between Black and White pts, further attention is necessary to assess potential disparities in use as time progresses. The use of CDK4/6i in the setting of HR+ve/HER2-ve MBC diminishes the differences in outcome between the two races.