Treatment of hepatitis C virus–associated mixed cryoglobulinemia with direct‐acting antiviral agents

Hepatitis C virus (HCV) is the most common cause of mixed cryoglobulinemia syndrome (MCS). The efficacy and safety of all‐oral direct‐acting antiviral (DAA) therapy in HCV‐associated MCS (HCV‐MCS) is largely unknown. The authors studied case series of patients with HCV‐MCS who were treated with sofosbuvir‐based regimens and historical controls treated with pegylated interferon and ribavirin in a single health care network. HCV‐MCS was defined by circulating cryoglobulin associated with systemic vasculitis symptoms. Renal involvement (n = 7) was established by kidney biopsy (n = 5) or by two or more of the following clinical findings: reduced kidney function, proteinuria, or hematuria with other causes excluded (n = 2). Twelve patients received DAA therapy between December 2013 and September 2014. Median age was 61 years, 58% were male, and 50% had cirrhosis. Median baseline serum creatinine was 0.97 mg/dL (range 0.7‐2.47). Four patients received rituximab concurrent with DAA therapy. Sustained virological response rate at 12 weeks (SVR12) was 83% overall. Patients with glomerulonephritis who achieved SVR12 experienced an improvement in serum creatinine and a reduction in proteinuria. Cryoglobulin levels decreased in 89% of patients, with median percent decreasing from 1.5% to 0.5% and completely disappearing in four of nine cases who had cryoglobulins measured after treatment. Serious adverse events were infrequent (17%). In contrast, the historical cohort treated with pegylated interferon and ribavirin experienced only 10% SVR12, with 100% experiencing at least one adverse event and 50% experiencing premature discontinuation due to adverse events. Conclusion: SVR12 rates for sofosbuvir‐based DAA regimens in HCV‐MCS were 83%, significantly higher than historical controls treated with pegylated interferon and ribavirin; patients with glomerulonephritis experienced improvement in renal function, including those not concomitantly treated with immunosuppression. (Hepatology 2016;63:408–417)