Study visits include screening, baseline/randomization (day 1), day 15, day 28 and then visits every 3 months for up to 2.5 years. A month is defined as 28 days. On study day 15, patients will receive the second dose of either rituximab or placebo; on study day 28 patients will begin treatment with GA therapy. Study days 15 and 28 have an acceptable window of +/- 4 days. Follow-up phone calls are conducted every month to assess adverse events and relapses. All monthly phone calls and quarterly visits must occur with a +/- 7 day window. Unscheduled office visits for the evaluation of symptoms suggestive of relapses will be scheduled as needed and may be prompted by questions elicited during the monthly safety and relapse assessment phone calls, or on the basis of a phone call initiated by the patient. In either case, those handling the phone call will interview the patient according to the questions described in Appendix D and a PDDS will be administered. If a subject reports new or worsening symptoms or there is a one point change in the PDDS score, an unscheduled visit will be necessary. The examining clinician will administer the Expanded Disability Status Scale (EDSS) but will be blinded to the PDDS score and type of visit (unscheduled or scheduled). The treating clinician will determine if the neurological change is considered a relapse based on EDSS scores provided by the EDSS evaluator and clinical presentation, and will make the decision whether or not corticosteroids should be administered for the treatment of a relapse. In addition, patients whose EDSS scores change sufficiently to qualify for SAD at either scheduled or unscheduled visits, will be asked to come in for an additional visit, 12 weeks later, to determine whether the change is sustained.