The FDA ( U.S. Food and Drug Administration ) has approved the therapeutic antibody Rituxan ( Rituximab ) in combination with Methotrexate to reduce signs and symptoms in adult patients with moderately-to-severely active rheumatoid arthritis who have had an inadequate response to one or more tumor necrosis factor ( TNF ) antagonist therapies.

Rituxan is the first treatment for rheumatoid arthritis that selectively targets immune cells known as CD20-positive B-cells. Through this unique mechanism of action, Rituxan may affect multiple pathways by which B-cells are believed to contribute to the initiation and development of rheumatoid arthritis.

The FDA based its approval decision for Rituxan for rheumatoid arthritis on data from three randomized, double-blind, placebo-controlled studies of patients with active rheumatoid arthritis.

Results of the pivotal Phase III trial known as REFLEX showed that a significantly greater proportion of patients who received a single treatment course of two infusions of Rituxan ( 1000 mg on days one and 15 ) with a stable dose of Methotrexate achieved American College of Rheumatology ( ACR ) 20, 50 and 70 response rates compared to patients who received placebo and Methotrexate.
The study included patients with active rheumatoid arthritis who had an inadequate response or were intolerant to prior treatment with one or more TNF antagonist therapies and current Methotrexate therapy.

At 24 weeks, patients receiving Rituxan displayed clinically and statistically significant improvements in rheumatoid arthritis signs and symptoms, including pain and disability. In patients receiving Rituxan:

- 51 percent achieved ACR 20, the primary endpoint of the study, versus 18 percent of placebo patients

- 27 percent achieved ACR 50, versus 5 percent of placebo patients

- 12 percent achieved ACR 70, versus 1 percent of placebo patients

Rituxan was also shown to reduce biologic markers of inflammation.

In REFLEX, the most frequently reported adverse events that occurred with Rituxan were primarily infusion-associated. Serious adverse events occurred in 7 percent of patients receiving Rituxan and Methotrexate compared to 10 percent in patients receiving placebo and Methotrexate.
Less than 1 percent of acute infusion reactions were serious.
The incidence of serious infections was 2 percent in Rituxan-treated patients and 1 percent in placebo-treated patients. The companies are committed to monitoring long-term safety of Rituxan.

Source: Genentech, 2006


XagenaMedicine2006