BackgroundImmune checkpoint inhibitors are a novel class of targeted therapy that activates T cell-mediated tumor cell death. Controversies exist about the safety and efficacy of immunotherapy in patients with chronic viral infections affecting T cells, such as hepatitis C virus (HCV). Herein, we analyzed the effect of immune checkpoint inhibitors on HCV viremia and HCV-related hepatic outcome.MethodsHCV-infected patients with solid tumors seen at MD Anderson Cancer Center (November 2012–April 2018) were enrolled in a prospective observational study. Patients were monitored for the development of HCV reactivation (HCV-RNA ≥1 log10IU/mL over baseline), hepatitis flare (alanine transaminase increase to ≥3 times upper limit of normal) and HCV-associated hepatitis (HCV reactivation and hepatitis flare) while on cancer treatment.ResultsOut of 205 chronically infected patients with solid tumors, 12 (6%) received immunotherapy and were seen in the HCV clinic, but only four (2%) returned for regular monitoring (Table 1). They were followed for 9 months. None of the four patients received concomitant chemotherapy or steroids. Hepatitis flare occurred in three patients, but HCV reactivation or HCV-associated hepatitis was not detected in any study patient. Immune checkpoint inhibitors were discontinued in one patient (25%) due to hepatitis flare unrelated to HCV.ConclusionThe use of immune checkpoint inhibitors appears to be safe in solid tumor patients with HCV infection.Table 1.Demographics, Types of Cancer, Immunotherapy Received, and Changes in Serum HCV-RNAPatientAge, yearsSexHCV GenotypeCirrhosisType of CancerImmunotherapyBaseline HCV-RNA (log 10IU/mL)Highest HCV-RNA After Baseline (log 10IU/mL)Hepatitis Flare 1 67Male1aYesHepatocellular carcinomaNivolumab + ipilimumab5.455.08Yes a 2 52Male1aNoMelanomaNivolumab + ipilimumab6.976.95Yes b 3 57Male3NoMelanomaPembrolizumab5.726.39No 4 55Male1aNoMelanomaIpilimumab5.757.18 cYes c a After partial hepatectomy. b Negative infectious work-up including hepatitis A, B, E, cytomegalovirus, and herpes simplex virus. c Six months after completing immunotherapy, HCV-associated hepatitis occurred after starting high-dose steroids for brain metastasis.Disclosures H. Torres, Gilead Sciences, Merck & Co., Inc.: Grant Investigator, Grant recipient. Vertex Pharmaceuticals: Grant Investigator, Grant recipient.