ROCKVILLE, Md., March 1 - The FDA today approved Rituxan (rituximab), a therapy for non-Hodgkin's lymphoma, for treatment of rheumatoid arthritis.
Rituxan was indicated for use in combination with methotrexate in patients with moderate-to-severe RA that has been refractory to treatment with Enbrel (etanercept) or Remicade (infliximab).
The approval came on the basis of results from a phase III trial called REFLEX (Efficacy and Safety of Rituximab in Active RA Patients who Experience an Inadequate Response to one or more Anti-TNF-α Therapies). This study found that 51% of 298 patients randomized to methotrexate plus Rituxan at 1,000 mg, versus just 18% of 201 patients in a methotrexate plus placebo arm, achieved at least a 20% improvement in the ACR20 score (P<0.0001).
Moreover, Rituxan demonstrated a significant improvement in ACR50 score (27% versus 5% [P<0.0001]) and ACR70, with 12% of patients reporting at least a 70% improvement in number of tender and/or swollen joints (P<0.0001). The REFLEX results were reported last November at the American College of Rheumatology meeting.
The REFLEX researchers said the difference in the two treatment groups was apparent after eight weeks and was sustained for six months after only two infusions of Rituxan two weeks apart.
Patients in REFLEX had failed 2.5 DMARDs and an average of 1.5 TNF inhibitors.
In a study published in the New England Journal of Medicine in 2004, a single course of two infusions of Rituxan, alone or in combination with either cyclophosphamide or continued methotrexate, provided significant improvement in disease symptoms at both weeks 24 and 48 in patients with active rheumatoid arthritis despite methotrexate treatment.
Rituxan is marketed by Genentech and Biogen Idec Inc.