Rates of Ibrutinib Uptake Among Black Patients with Lymphoma in SEER-Medicare Increased over Time

Introduction

Disparities in treatments and survival outcomes have been documented in non-Hodgkin lymphomas (NHL). In the past decade, the Food and Drug Administration (FDA) has approved several new oral therapy options, including ibrutinib, lenalidomide, acalabrutinib, and idelalisib, for the treatment of several NHL subtypes. We hypothesized that racial and socioeconomic disparities would lead to delayed uptake of oral therapy options in older patients with NHL.

Methods

The Medicare Part D dataset, part of the SEER-Medicare linked dataset, was used to identify claims for ibrutinib, acalabrutinib, idelalisib, and lenalidomide from date of drug approval through 2019. Patients with mantle cell lymphoma (MCL), marginal zone lymphoma (MZL), chronic lymphocytic leukemia (CLL), Waldenstrom's macroglobulinemia (WM), and follicular lymphoma (FL) were included since the four oral drugs were approved for their use. Variables reflecting possibly racial and socioeconomic disparities, including race (White, Black, vs Asian, Pacific Islander, and Native American Indian [Asian/PI/NAI]), ethnicity (Hispanic vs non-Hispanic), % poverty and % urban of census tract, and Medicaid eligibility, were included. Bar plots were generated of number of patients with prescriptions for each of the oral drugs over time to assess for rate of uptake and impact of above variables on uptake rate. Cochran Armitage tests were used to test for trend.

Results

In total, 43,636 patients were included in this analysis, among whom 4,832 (19.4%) had MCL, 8,447 (33.9%) had CLL, 209 (0.8%) had WM, 11,439 (45.9%) had MZL, and 18,691 (42.8%) had FL. Most were White (92.6%), non-Hispanic (95.0%), and from census tracts with <20% poverty (81.0%). 3% of patients were dual-eligible for Medicaid at time of diagnosis. The percentage of Black patients in the total population was 3.9%, compared to 2.5%, 6%, 2.4%, 4.5%, and 3% among patients with MCL, CLL, WM, MZL, and FL, respectively ( Figure A).

The number of ibrutinib prescriptions increased from 66 in 2013 to 5,083 in 2019, corresponding to 41 and 589 patients, respectively. The number of acalabrutinib prescriptions also increased from 7 in 2017 to 590 in 2019, corresponding to 5 and 94 patients, respectively. Prescriptions for lenalidomide also increased from 276 in 2013 to 831 in 2019, corresponding to 79 and 148 patients, respectively. Finally, prescriptions for idelalisib started at 98 in 2014, peaked at 395 in 2016, and dropped to 95 by 2019, corresponding to 38, 78, and 20 patients, respectively.

Among patients who received ibrutinib prescriptions, the proportion of Black patients increased from 2.4% in 2013 to 5.8% in 2019. The proportion of Black and Asian/PI/NAI increased from 2.4% in 2013 to 9.5% in 2019 ( P for trend=0.0006) ( Figure B). A similar trend was not seen for any of the other three oral agents related to race, nor were any trends noted among all four oral agents for ethnicity, census tract % poverty, census tract % urban, and Medicaid eligibility across time.

Discussion

In this SEER-Medicare analysis, we found that race appeared to play a factor in prescriptions of ibrutinib, with prescriptions to Black patients gradually increasing over time, despite starting at a proportion even smaller than the proportion of Black patients in the overall dataset. Limitations of this study include limited sampling in SEER-Medicare of patients of minority races as well as potential for missed prescriptions that were not paid for by Medicare. Additionally, we were limited to an assessment of disease incidence rather than prevalence, which may impact proportions of patients using novel oral agents. Overall, these findings suggest that race may continue to play a role in access to care related to novel agents, while oral agents may offer improved equality related to other variables commonly associated with access to care.