Editor note: On 3/01/2006, Rituxan was FDA approved to be used in combination with methotrexate to treat rheumatoid arthritis by reducing the signs and symptoms in adult patients who have moderately-to-severely active rheumatoid arthritis and have failed one or more anti-TNF drugs e.g. Enbrel (etanercept), Remicade (infliximab), or Humira (adalimumab). See: Rituxan Approved For Rheumatoid Arthritis - The Facts of Rituxan
Rituxan Phase II Clinical Study
Results from Phase II clinical trials for Rituxan were announced by Genentech, IDEC Pharmaceuticals, and Roche, at the 2003 American College of Rheumatology meeting in Orlando, Florida. A single, short course of treatment with Rituxan (two infusions during the first 15 days of treatment) alone, or in combination with methotrexate or cyclophosphamide improved symptoms in patients with moderate to severe rheumatoid arthritis for up to 48 weeks, compared to methotrexate alone.
In the study, patients who had completed the prior 24-week trial were followed so researchers could assess duration of response beyond the initial endpoint of 24 weeks. 161 participants in the four-arm, blinded, placebo-controlled study were randomized to receive either:
- Rituxan alone (2 infusions of 1 g)
- Rituxan (2 infusions of 1 g) plus Methotrexate (10 mg weekly).
- Rituxan (2 infusions of 1 g) plus Cyclophosphamide (2 infusions of 750 mg)
- Methotrexate alone (10 mg weekly).
- Each group also received a 17-day course of corticosteroids (total dose 910 mg)
- Rituxan was infused on days one and 15 of the study only.
Study Results
At 48 weeks, patients receiving Rituxan and Methotrexate experienced the greatest improvement in symptoms:
- 65% of participants showed at least a 20% improvement in symptoms (ACR 20).
- 35% of participants showed at least a 50% improvement in symptoms (ACR 50).
- 15% of participants showed at least s 70% improvement (ACR 70).
Results from patients receiving Rituxan and Cyclophosphamide:
- 44% of participants experienced ACR 20.
- 22% of participants experienced ACR 50.
- 10% of participants experienced ACR 70.
For the patients receiving Rituxan alone:
- 30% experienced ACR 20.
- 13% experienced ACR 50.
- 8% experienced ACR 70.
The results reveal for patients taking methotrexate alone:
- 20% experienced ACR 20.
- 5% experienced ACR 50.
- None experienced ACR 70.
Study Conclusions
The phase II results contribute to the knowledge that B-cells (b-lymphocytes) play a role in immune-mediated inflammatory diseases including rheumatoid arthritis. The makers of the drug have initiated global randomized studies evaluating Rituxan as a treatment for rheumatoid arthritis, including a pivotal phase III study known as REFLEX for patients who have had an inadequate response to anti-TNF drugs and a phase IIb study known as DANCER for patients who have had an inadequate response to DMARDs.
Rituxan is a monoclonal antibody and works by targeting B-cells. Rituxan is already a successful treatment for cancer. More clinical trial results will determine its value for treating rheumatoid arthritis and if Rituxan is ultimately approved by the FDA for the treatment of rheumatoid arthritis.
Related Resources - Rituxan (Rituximab)
Related Resources - Rheumatoid Arthritis
Source: Genentech PRESS RELEASE, October 26, 2003
