Abstract No. 559 Safety and Efficacy of Radioembolization in HIV+ Patients with Hepatocellular Carcinoma

Radioembolization with yttrium-90 (Y90) induces necrosis in hepatocellular carcinoma (HCC) partly through the upregulation of tumor-infiltrating lymphocytes. HIV targets CD4 cells, which may affect the post-radioembolization immune response to tumor neoantigens. The effect of Y90 on peripheral T cells, especially in an HIV+ population, are yet unstudied. This study aims to assess the safety and efficacy of Y90 for the treatment of early and intermediate stage HCC in patients with HIV, as well as the effects of Y90 on CD4 counts in this population. A retrospective review of all patients with HIV who underwent Y90 for the treatment of HCC at a single academic institution between 1/1/2012 and 8/1/2023 was conducted. Patients not on antiretroviral therapy or with advanced/terminal-stage HCC (BCLC C/D) were excluded; 24 patients (mean age, 61.4±10.5, 83.3% male) were analyzed. Imaging response was evaluated with Modified Response Evaluation Criteria in Solid Tumors (mRECIST), and median progression-free survival (PFS) and overall survival (OS) were calculated with Kaplan-Meier analysis. Common Terminology Criteria for Adverse Events (CTCAE) v. 5.0 was used to grade adverse events. 8 patients who had HIV-related labs recorded within 75 days prior to and after Y90 were included in the laboratory analysis. Univariate statistics were used to identify differences in CD4 counts and viral loads before and after radioembolization. Target lesion (mean size, 3.90±2.83 cm) overall response rate and disease control rate were both 100% (17 CR, 7 PR, 0 SD, 0 PD). Median PFS was 17.4 months and median OS was 80.3 months. 29.2% of patients had grade 1/2 adverse events, with no grade 3/4 adverse events. No infection-related adverse events were encountered. The mean pre- and post-Y90 CD4 counts were 393.8/mL and 208.4/mL (p=0.050), with a mean decrease of 185.4/mL (range 17-501). Viral loads were undetectable before and after Y90 (p=1.0). This small single-center retrospective study demonstrates that Y90 can treat early and intermediate HCC in HIV+ patients with a low rate of adverse events and excellent index lesion response by mRECIST. CD4 counts are widely monitored for infection risk and pre-operative clearance for subsequent therapies and orthotopic liver transplant, which makes the potential impact of Y90 on CD4 count of particular importance to those with HIV. After Y90, CD4 effector T cell levels in this cohort decreased without a significant change in viral load or infection, suggesting the importance of laboratory monitoring in this patient population.