A Phase III clinical study of Rituximab ( Rituxan ) met its primary endpoint of a greater proportion of Rituximab-treated patients achieving an American College of Rheumatology ( ACR ) 20 response at week 24, compared to placebo.

The study included patients with active rheumatoid arthritis ( RA ) who have had an inadequate response or were intolerant to prior treatment with one or more anti-TNF therapies.

In this study, known as REFLEX ( Randomized Evaluation of Long-term Efficacy of Rituximab in RA ), patients who received a single treatment course of two infusions of Rituximab with a stable dose of Methotrexate ( MTX ) displayed a statistically significant improvement in symptoms compared to patients who received placebo and MTX.

A preliminary analysis of the data did not reveal any unexpected safety signals. The most common side effects in the Rituximab arm included headache, upper respiratory tract infection and nasopharyngitis.

These new Phase III data follow recent positive preliminary findings from a Phase IIb study that evaluated the efficacy and safety of Rituximab in moderate-to-severe RA patients who failed prior treatment with at least one disease-modifying anti-rheumatic drug ( DMARD ).

The REFLEX trial enrolled 520 patients from the United States, Canada and Europe.
The patients were randomized to receive either Rituximab ( 1000 mg i.v. on days one and 15 ) or placebo.
All patients received a stable dose of MTX and a two-week course of corticosteroids.

Rheumatoid arthritis is a debilitating autoimmune disease that affects more than two million Americans and hinders the daily activities of sufferers.
RA occurs when the immune system inappropriately attacks joint tissue, causing chronic inflammation and irreversible destruction of cartilage, tendons and bones, often resulting in disability.
While RA has traditionally been considered a T-cell–mediated disease, emerging research suggests that other immune cells called B cells may play multiple roles in the pathophysiology of RA including autoantibody production, T-cell activation and cytokine production.

Rituximab is a therapeutic antibody that targets and selectively depletes peripheral CD20 positive B cells without targeting stem cells or existing plasma cells.

Source: Genentech, 2005


XagenaMedicine2005