Patients on Rituximab Not Properly Screened for HBV

Less than half of patients treated with rituximab for hematologic or oncologic (hem/onc) purposes are screened for hepatitis B virus (HBV) prior to or shortly after therapy initiation, according to a study presented at the American Society of Hematology annual meeting (Atlanta; Dec. 8 to 11). Low pretreatment screening rates demonstrate the need for continued efforts to implement evidence-based HBV screening and prophylaxis guidelines in clinical practice, the researchers say. The researchers from UMass Memorial Medical Center (Worcester, Mass.) retrospectively analyzed data (2005 to 2011) from 103 hem/onc patients over the age of 17 years  who received the monoclonal antibody rituximab (45 percent had diffuse large B-cell lymphoma, 15 percent had other high-grade lymphoma, 14 percent had follicular lymphoma, and 26 percent had another hematologic malignancy). The researchers found that a total of 53 (51.4 percent) were screened for HBV at any point before or during treatment. Only 6.8 percent of patients were screened prior to initiation of treatment and 18.4 percent had HBV screening within 30 days of the first rituximab dose. The median time to screening in patients screened for HBV after 30 days was 196 days after rituximab initiation. Year of therapy did not affect rates of HBV screening. Of the 53 patients screened for HBV prior to or within 30 days of rituximab initiation, eight (15.1 percent) were positive for HBV infection and three were positive for HBsAg, all of whom received HBV anti-viral prophylaxis. Five patients who were negative for HBsAg were positive for HBcAb, and only one of them received anti-viral prophylaxis. Reactivation of HBV in patients taking rituximab has been documented in both patients at high risk of reactivation (HBV surface antigen [HBVsAg] positive) and in lower-risk populations (HBVsAg negative, HBV core antibody positive), where the risk of reactivation with rituximab-based therapy has been cited as 15 percent to 20 percent. Among the 53 patients in this study who underwent HBV screening, there were no cases of HBV reactivation observed over a median follow-up time of 15.6 months. “Altogether, there remains a critical need for standardized recommendations and consensus for screening and prophylaxis of HBV infection in patients who receive rituximab therapy,” conclude the authors, led by Jayde Bednarik, Pharm.D.