Reducing the Signs and Symptoms: Initial and Re-Treatment Courses

The efficacy and safety of rituximab were evaluated in two randomized, double-blind, placebo-controlled studies of adult patients with moderately to severely active RA who had a prior inadequate response to at least one TNF inhibitor. Patients were 18 years of age or older, diagnosed with active RA according to American College of Rheumatology (ACR) criteria, and had at least 8 swollen and 8 tender joints.

In RA Study 1 (NCT00468546), patients were randomized to receive either rituximab 2×1,000 mg+MTX or placebo +MTX for 24 weeks. Further courses of rituximab 2×1,000 mg+MTX were administered in an open label extension study at a frequency determined by clinical evaluation, but no sooner than 16 weeks after the preceding course of rituximab. In addition to the intravenous premedication, glucocorticoids were administered orally on a tapering schedule from baseline through Day 14. The proportions of patients achieving ACR 20, 50, and 70 responses at Week 24 of the placebo-controlled period are shown in Table 11.

In RA Study 2 (NCT00266227), all patients received the first course of rituximab 2 × 1,000 mg + MTX. Patients who experienced ongoing disease activity were randomized to receive a second course of either rituximab 2 × 1,000 mg + MTX or placebo + MTX, the majority between Weeks 24–28. The proportions of patients achieving ACR 20, 50, and 70 responses at Week 24, before the re-treatment course, and at Week 48, after retreatment, are shown in Table 11.

Improvement was also noted for all components of ACR response following treatment with rituximab, as shown in Table 12.

The time course of ACR 20 response for RA Study 1 is shown in Figure 2. Although both treatment groups received a brief course of intravenous and oral glucocorticoids, resulting in similar benefits at Week 4, higher ACR 20 responses were observed for the rituximab group by Week 8. A similar proportion of patients achieved these responses through Week 24 after a single course of treatment (2 infusions) with rituximab. Similar patterns were demonstrated for ACR 50 and 70 responses.

Radiographic Response

In RA Study 1, structural joint damage was assessed radiographically and expressed as changes in Genant-modified Total Sharp Score (TSS) and its components, the erosion score (ES) and the joint space narrowing (JSN) score. Rituximab + MTX slowed the progression of structural damage compared to placebo + MTX after 1 year as shown in Table 13.

In RA Study 1 and its open-label extension, 70% of patients initially randomized to rituximab + MTX and 72% of patients initially randomized to placebo + MTX were evaluated radiographically at Year 2. As shown in Table 13, progression of structural damage in rituximab + MTX patients was further reduced in the second year of treatment.

Following 2 years of treatment with rituximab + MTX, 57% of patients had no progression of structural damage. During the first year, 60% of rituximab + MTX treated patients had no progression, defined as a change in TSS of zero or less compared to baseline, compared to 46% of placebo + MTX treated patients. In their second year of treatment with rituximab + MTX, more patients had no progression than in the first year (68% vs. 60%), and 87% of the rituximab + MTX treated patients who had no progression in the first year also had no progression in the second year.

Lesser Efficacy of 500 Vs. 1,000 mg Treatment Courses for Radiographic Outcomes

RA Study 3 (NCT00299104) is a randomized, double-blind, placebo-controlled study which evaluated the effect of placebo + MTX compared to rituximab 2 × 500 mg + MTX and rituximab 2 × 1,000 mg + MTX treatment courses in MTX-naïve RA patients with moderately to severely active disease. Patients received a first course of two infusions of rituximab or placebo on Days 1 and 15. MTX was initiated at 7.5 mg/week and escalated up to 20 mg/week by Week 8 in all three treatment arms. After a minimum of 24 weeks, patients with ongoing disease activity were eligible to receive re-treatment with additional courses of their assigned treatment. After one year of treatment, the proportion of patients achieving ACR 20/50/70 responses were similar in both rituximab dose groups and were higher than in the placebo group. However, with respect to radiographic scores, only the rituximab 1,000 mg treatment group demonstrated a statistically significant reduction in TSS: a change of 0.36 units compared to 1.08 units for the placebo group, a 67% reduction.

Physical Function Response

RA Study 4 (NCT00299130) is a randomized, double-blind, placebo-controlled study in adult RA patients with moderately to severely active disease with inadequate response to MTX. Patients were randomized to receive an initial course of rituximab 500 mg, rituximab 1,000 mg, or placebo in addition to background MTX.

Physical function was assessed at Weeks 24 and 48 using the Health Assessment Questionnaire Disability Index (HAQ-DI). From baseline to Week 24, a greater proportion of rituximab-treated patients had an improvement in HAQ-DI of at least 0.22 (a minimal clinically important difference) and a greater mean HAQ-DI improvement compared to placebo, as shown in Table 14. HAQ-DI results for the rituximab 500 mg treatment group were similar to the rituximab 1,000 mg treatment group; however radiographic responses were not assessed Dosing Precaution in the Radiographic Responses section above). These improvements were maintained at 48 weeks.