SOUTH SAN FRANCISCOThe FDA has approved a supplemental biological license application (sBLA) for Rituxan (rituximab), the monoclonal antibody developed by Genentech, Inc. and IDEC Pharmaceuticals (San Diego) for treatment of patient with relapsed or refractory, low-grade or follicular, CD20-positive, B-cell non-Hodgkin’s lymphoma (NHL). The new product labeling includes re-treatment with rituximab(Drug information on rituximab) after a prior course, initial treatment with eight weekly infusions instead of four, and treatment of bulky disease.
In a phase II multicenter single-arm study, 60 NHL patients were re-treated when they relapsed after obtaining an objective clinical response with their initial 4-week course of rituximab once a week. The overall response rate was 38%, with 10% achieving a complete response. The projected median duration of response is 15 months.
In another phase II multicenter single-arm study, 37 NHL patients received 375 mg/m2 of rituximab once a week for a total of eight weekly infusions. The overall response rate was 57% (14% complete responses). The projected median response duration is 13.4 months.
Results also were submitted from multiple rituximab studies of 39 low-grade NHL patients with relapsed or refractory bulky disease. The overall response rate was 36%, with 3% achieving a complete response. The median duration of response was 6.9 months. Each patient received 375 mg/m2 of rituximab in four weekly infusions.
In addition, the revised package insert will emphasize already existing safety information concerning rare severe and potentially fatal mucocutaneous reactions that have occurred in patients who have received rituximab.
Patients experiencing these reactions have highly compromised immune systems related to their disease, the companies said. Currently, there has been no direct link made between these types of reactions and rituximab use. However, until more is known, it is important that physicians understand that rituximab could have contributed to some of these events and manage their patients accordingly.