Abstract 745: Burden of potential HIV and cancer-related treatment drug-drug interactions: An analysis of SEER-Medicare
Authors: Islam Jessica Yasmine , Zhou Xi , Baggett Christopher , Jamjian Christine , Coghill Anna E. , Suneja Gita , Lund Jennifer L. 
Published: April 2023

Abstract
Background: People living with HIV (PLWH) are less likely to receive any cancer treatment, however, reasons for this disparity are unclear. One factor may be oncologists’ concerns regarding potential drug-drug interactions (DDIs) between cancer and HIV treatments, and their downstream consequences on clinical outcomes. Our objective was to characterize potential DDIs among PLWH diagnosed with common non-AIDS cancers within the year following cancer diagnosis.
Methods: We leveraged the SEER-Medicare database (2007-2018) to identify individuals over the age of 64 diagnosed with breast, colorectal, non-small cell lung (NSCLC), and prostate cancer with Medicare fee-for-service coverage. PLWH were identified using ICD-9 (042-044 or V08) and ICD-10 (B20-B24 or Z21) codes, either at or prior to cancer diagnosis. Participants were required to have continuous enrollment in Medicare Part D (prescription events) from their cancer diagnosis to at least 12 months after their cancer diagnosis (or death) to observe potential changes in highly active antiretroviral therapy use. Potential DDIs between systemic cancer therapies and HAART were identified based on National Comprehensive Cancer Network (NCCN) guidelines and pharmacist input. We estimated the 12-month prevalence of exposure to a potential DDI following cancer diagnosis and identified sociodemographic determinants of exposure to a potential DDI exposure using multivariable Poisson regression.
Results: We identified 667 eligible individuals of whom, 41% had prostate cancer, 34% NSCLC, 16% colorectal and 8% breast cancer. Overall, 46% of participants were NH-Black, 61% 65-70 years of age, 82% men, and 98% resided in urban areas. Sixty-one percent had a low-income subsidy at the time of cancer diagnosis and 45% were dually insured with Medicaid. Overall, 32% received chemotherapy, 16% received hormone therapy, 40% received radiation, and 31% received surgical treatment. Twenty-eight percent received no cancer treatment within one year of their diagnosis, which included 11% for breast, 34% for colorectal, 28% for NSCLC, and 28% for prostate cancers. Eight percent (53/667) overall and 25% (53/212) of those who received chemotherapy were at risk for a potential DDI. Women were more likely to experience a potential DDI (13% vs. 7%, p=0.016), as well as those residing in the South (15% vs. 6% in the Northeast and 5% in the Midwest/West; p=0.001) and those diagnosed with late-stage cancer (17% vs. 1.8%, p&lt;0.001). On multivariable analyses of those at risk of a potential DDI (n=212), NH-Black adults (vs. NH-White; aRR: 1.85; 95% CI: 1.08-3.17), women (vs. men; aRR: 2.16; 1.38-3.37), and those with late-stage cancer (vs. early stage; aRR: 4.87; 95% CI: 1.87-12.70) were more likely to experience a potential DDI.
Conclusion: One-quarter of those receiving systemic therapy were exposed to a potential DDI with those diagnosed at late stage, at highest risk.
Citation Format: Jessica Yasmine Islam, Xi Zhou, Christopher Baggett, Christine Jamjian, Anna E. Coghill, Gita Suneja, Jennifer L. Lund. Burden of potential HIV and cancer-related treatment drug-drug interactions: An analysis of SEER-Medicare [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 745.