Rituxan® (rituximab)

Parent companies: Genentech and Biogen Idec

• Administered via intravenous infusion.
  
  
• Rituxan is amonoclonal antibody (CD20, from mouse tissue) that binds to a receptor on the surface of B cells. These cells are then destroyed and their levels in the circulation are decreased. It is approved for use in the treatment ofmany lymphomas, leukemias, and autoimmune disorders.
  
  
• A Phase I/II double-blind study of 80 people with low-inflammatory SPMS, sponsored by the National Institute of Neurologic Diseases and Stroke, is testing Rituxan versus placebo (RIVITaLISe). The study is still recruiting participants. The primary outcome measure will be the progression of brain atrophy after two years of treatment, unless predetermined analysis shows that the secondary outcome measures of MRI and clinical assessment are more reliable measures of effectiveness than brain atrophy.
  
  
• A Phase II trial examined the effect of a single course of treatment in RRMS, with two infusions of 1,000 mg each, administered two weeks apart. At 24 and 48 weeks, the number of active lesions was reduced by 91 percent and relapses were reduced by 58 percent.
  
  
• The drug was also tested in 30 people with RRMS who had experienced continued clinical activity despite treatment with one of the approved disease-modifying therapies. Participants received two doses of Rituxan, two weeks apart, while continuing to take their usual medication. MRI scans were performed to look for areas of inflammatory lesions at weeks 4, 12, 16, 18, and 24. Multiple Sclerosis Functional Composite (MSFC) and EDSS scores were obtained at baseline and throughout the post-treatment follow-up to determine changes in function and mobility. Gadolinium-enhancing lesions were reduced after treatment with Rituxan; 74 percent of post-treatment MRI scans were free of gadolinium-enhancing activity as compared with 26 percent free of gadolinium-enhancing activity at baseline. Median gadolinium-enhancing lesions were reduced from 1.0 to 0, and there was an 88-percent reduction in the mean number of these lesions. The MSFC improved, while the EDSS remained stable.
  
  
• Serious adverse events have been reported in Rituxan-treated patients with other diseases, including Progressive Multifocal Leukoencephalopathy (PML), an often-fatal viral infection of the brain (as with Tysabri); patients must be closely monitored.