Edward M. Vital

Reduction of fatigue in Sjögren syndrome with rituximab: results of a randomised, double-blind, placebo-controlled pilot study

Objective: Primary Sjögren syndrome (pSS) causes significant systemic symptoms including fatigue as well as glandular dysfunction. There are currently no effective systemic therapies; however, open label series have suggested that rituximab may be beneficial for systemic and glandular manifestations. Therefore, we performed a double blind, placebo-controlled, randomised pilot study of the efficacy of rituximab in reducing fatigue in pSS. Methods: A total of 17 patients with pSS and a score on fatigue visual analogue scale (VAS) >50 were randomised to receive either 2 infusions of rituximab 1 g or placebo; patients also received oral and intravenous steroids. Outcome measures included: the proportion of patients with >20% reduction in fatigue VAS, changes in pSS related symptoms, health related quality of life and immunological parameters of pSS. These were measured 6 months after therapy. Results: There was significant improvement from baseline in fatigue VAS in the rituximab group (p<0.001) in contrast to the placebo group (p = 0.147). There was a significant difference between the groups at 6 months in the social functioning score of SF-36 (p = 0.01) and a trend to significant difference in the mental health domain score of SF-36 (p = 0.06). There was one episode of serum sickness in the rituximab treated group. Conclusions: This is the first double blind study of rituximab in pSS to show benefit; further studies are justified.

Highly sensitive B cell analysis predicts response to rituximab therapy in rheumatoid arthritis

OBJECTIVE In rheumatoid arthritis (RA), B cell depletion occurs in all patients treated with rituximab, but the clinical responses to rituximab are variable. A highly sensitive assay was used to test the hypothesis that B cell depletion is variable, and that incomplete depletion leads to a poorer outcome. METHODS Sixty patients with active RA unresponsive to anti-tumor necrosis factor agents received two 1-gram infusions of rituximab. B cell numbers were measured by highly sensitive flow cytometry before and after each infusion and at 3-month intervals thereafter. A reduction in B cell levels below 0.0001x10(9)/liter was defined as complete depletion (compared with 0.05x10(9)/liter by conventional cytometry). Clinical responses were measured using the European League Against Rheumatism (EULAR) criteria. RESULTS At 6 months, 92% of patients had a moderate-to-good clinical response according to the EULAR criteria. B cells were detected in 63% of patients after the first infusion of rituximab (median level 0.0009x10(9)/liter [range<0.0001-0.0015x10(9)/liter), and these patients had poorer clinical outcomes than patients with complete depletion. At 9 months, 82% of patients with complete depletion had a moderate-to- good EULAR response, compared with 43% of those with partial depletion (P=0.01). At 12 months, 59% of complete responders had a moderate-to-good EULAR response, compared with 21% of those with partial depletion (P=0.01). Patients in whom B cells were depleted only after the second infusion did no better than those in whom depletion was never complete and had poorer clinical outcomes than those in whom depletion was initially complete. CONCLUSION This study is the first to show, using a highly sensitive analysis, that rituximab therapy is associated with variable diminution in B cell numbers. A lack of complete depletion of B cells after 1 infusion was associated with a poorer outcome.

Efficacy of rituximab in 164 patients with biopsy-proven lupus nephritis: Pooled data from European cohorts

OBJECTIVE To present a pooled analysis of the efficacy of rituximab from European cohorts diagnosed with biopsy-proven lupus nephropathy (LN) who were treated with rituximab. METHODS Consecutive patients with biopsy-proven LN treated with rituximab in European reference centers were included. Complete response (CR) was defined as normal serum creatinine with inactive urinary sediment and 24-hour urinary albumin <0.5 g, and partial response (PR) as a >50% improvement in all renal parameters that were abnormal at baseline, with no deterioration in any parameter. RESULTS 164 patients were included (145 women and 19 men, with a mean age of 32.3 years). Rituximab was administered in combination with corticosteroids (162 patients, 99%) and immunosuppressive agents in 124 (76%) patients (cyclophosphamide in 58 and mycophenolate in 55). At 6- and 12-months, respectively, response rates were 27% and 30% for CR, 40% and 37% for PR and 33% for no response. Significant improvement in 24-h proteinuria (4.41 g. baseline vs 1.31 g. post-therapy, p=0.006), serum albumin (28.55 g. baseline to 36.46 g. post-therapy, p<0.001) and protein/creatinine ratio (from 421.94 g/mmol baseline to 234.98 post-therapy, p<0.001) at 12 months was observed. A better response (CR+PR) was found in patients with type III LN in comparison with those with type IV and type V (p=0.007 and 0.03, respectively). Nephrotic syndrome and renal failure at the time of rituximab administration predicted a worse response (no achievement of CR at 12 months) (p<0.001 and p=0.024, respectively). CONCLUSION Rituximab is currently being used to treat refractory systemic autoimmune diseases. Rituximab may be an effective option for patients with lupus nephritis, especially those refractory to standard treatment or who experience a new flare after intensive immunosuppressive treatment.

B cell biomarkers of rituximab responses in systemic lupus erythematosus

OBJECTIVE Rituximab appears to be effective in many studies of systemic lupus erythematosus (SLE), with variable initial clinical response and time to relapse. However, results of a randomized controlled trial of rituximab were negative. This study was undertaken to evaluate the effectiveness of rituximab in SLE, using highly sensitive flow cytometry (HSFC), which can define B cell numbers 50-100 times lower than conventional techniques and predicts responses in rheumatoid arthritis. METHODS Thirty-nine patients with active SLE were started on a standard regimen of rituximab with intravenous and oral steroids. Clinical response and relapse were defined using the British Isles Lupus Assessment Group (BILAG) index with criteria for major clinical response, partial clinical response, and nonresponse. HSFC, including analysis of B cell subsets, was performed. RESULTS There was a significant reduction from baseline in global BILAG score at all time points analyzed (P<0.0001), and major clinical response and partial clinical response rates were 51% and 31%, respectively. Time to relapse was highly variable. Fifty percent of the patients relapsed after 6-18 months (earlier relapse); the remainder relapsed at a slower rate (later relapse). B cell depletion and repopulation were variable and were predictive of these clinical outcomes. There was a persistent B cell presence in 21 patients after 2 infusions of rituximab, which included all 7 patients with no response (P=0.012 versus patients with complete depletion of B cells). Memory B cell (P=0.02) and plasmablast (P<0.001) repopulation after 26 weeks was markedly faster in patients with earlier relapse versus patients with later relapse. CONCLUSION Our findings indicate that rituximab is effective in SLE, and clinical responses are supported by close correlation with B cell numbers. HSFC is a valuable tool in the assessment and prediction of response in SLE.

Management of nonresponse to rituximab in rheumatoid arthritis: Predictors and outcome of re-treatment

OBJECTIVE A proportion of patients with rheumatoid arthritis (RA) have disease that fails to respond to an initial cycle of rituximab. Using highly sensitive flow cytometry (HSFC), it has been shown that most patients who do not exhibit a response, as measured using the European League Against Rheumatism (EULAR) criteria, have persistent circulating B cell levels at week 2 after initial treatment with rituximab. This study was undertaken to examine whether an additional cycle of rituximab would improve B cell depletion and clinical response in patients whose disease did not respond to the initial cycle. METHODS Patients with RA (n = 158) were treated with a first cycle of rituximab (2 infusions of 1 gm each). Clinical responses were assessed using EULAR criteria, and patients were categorized as either first-cycle responders or first-cycle nonresponders. Baseline characteristics of first-cycle nonresponders (n = 38) and first-cycle responders (n = 65) with complete data were compared. First-cycle nonresponders (n = 25) were treated with a second cycle of rituximab at least 6 months after the first cycle. HSFC was performed at baseline, immediately prior to the second infusion (week 2), 1 month after the second infusion (week 6), and then every 3 months for each cycle of rituximab. Complete B cell depletion was defined as being <0.0001 x 10(9) cells/liter. RESULTS At baseline, the number of preplasma cells was significantly higher in first-cycle nonresponders than in first-cycle responders (P = 0.003). Following the first infusion of the first cycle of rituximab, only 9% of first-cycle nonresponders (3 of 34) exhibited complete depletion of B-lineage cells, compared with 37% of first-cycle responders (22 of 59) (P = 0.007). Following the first infusion of the second cycle of rituximab, 38% of first-cycle nonresponders exhibited complete depletion. Twenty-six weeks after the second cycle, there was a significant improvement in the Disease Activity Score in 28 joints, with 72% of patients exhibiting a EULAR response. CONCLUSION RA patients whose disease did not respond to an initial cycle of rituximab have higher circulating preplasma cell numbers at baseline and incomplete depletion. Our findings indicate that an additional cycle of rituximab administered prior to total B cell repopulation enhances B cell depletion and clinical responses.

Reduced-dose rituximab in rheumatoid arthritis: efficacy depends on degree of B cell depletion.

OBJECTIVE Studies comparing 500 mg rituximab and 1,000 mg rituximab doses in rheumatoid arthritis have yielded conflicting data on clinical outcomes, but in all of these studies a subgroup of patients has had excellent responses at the lower dose. Historically, it was considered that rituximab uniformly depleted B cells at both doses. Using highly sensitive assays, we have shown that B cell depletion is variable and predictive of clinical response. Using the same techniques, we undertook the present study to test the hypothesis that the level of B cell depletion, rather than the rituximab dose, determines clinical response. METHODS Nineteen patients were treated with two 500-mg infusions of rituximab, and 61 patients were treated with two 1,000-mg infusions of rituximab. Highly sensitive flow cytometry was performed at 0, 2, 6, 14, and 26 weeks. European League Against Rheumatism (EULAR) response rates at 6 months were compared between patients with and those without complete depletion at each dose. RESULTS The median B cell count was numerically higher at all time points following therapy in the 500 mg rituximab group. Twenty-five percent of patients in the 500 mg rituximab group had complete depletion at 2 weeks, compared with 49% of those in the 1,000 mg rituximab group. Complete depletion at 2 weeks after treatment with 500 mg rituximab was associated with lower baseline preplasma cell counts (P = 0.047). Most patients responded after either dose, but response was related to B cell depletion. Notably, in the 500 mg rituximab group all patients with complete depletion had a EULAR good response (P = 0.011). CONCLUSION This pilot study suggests that the degree of B cell depletion, rather than the dose of rituximab, determines clinical response. It may be possible to predict which patients will respond to lower-dose rituximab, and this may allow more cost-effective treatment.

Abatacept in the treatment of rheumatoid arthritis.

T-cell biology has regained importance in the pathogenesis of rheumatoid arthritis. Despite the significant improvements associated with the introduction of tumor necrosis factor-α blockade, reasonable proportions of failures and suboptimal responses have been reported, necessitating a search for alternative targeted therapies. This has included drug therapy designed to interrupt T-cell activation via the co-stimulation pathway. Abatacept is a recombinant fusion protein that blocks the co-stimulatory signal mediated by the CD28-CD80/86 pathway, which is required for T-cell activation. Several clinical trials have confirmed the safety and efficacy of this drug in the treatment of rheumatoid arthritis. This review summarizes the clinical data supporting this line of treatment and considers the safety and efficacy data from phase II and III trials.

Rituximab: novel B-cell depletion therapy for the treatment of rheumatoid arthritis

Significant numbers of patients with rheumatoid arthritis (RA) suffer from disease that is refractory to both conventional therapy and newer biological agents such as TNF-α inhibitors. These patients may respond insufficiently, lose an effective response, develop toxicity or carry contraindications to such agents. Rituximab, a chimeric monoclonal antibody against CD20 that effectively depletes B cells in peripheral blood, has been licensed for the treatment of certain haematological malignancies for almost 10 years. B cells are now known to have multiple key roles in the pathogenesis of RA. Data is now available that indicates efficacy and safety of B-cell depletion with rituximab in the treatment of RA in a variety of patient groups. The clinical outcomes from these studies, together with its safety profile, have led to rituximab being licensed for the treatment of patients with RA who have failed to obtain benefit from anti-TNF-α agents.

The development of targeted therapies in rheumatoid arthritis

The therapy of rheumatoid arthritis has been revolutionised by advances in the understanding of disease at a cellular and molecular level accompanied by the technology to target specific mediators of disease. Proposed therapeutic targets from in vitro and animal models however have frequently resulted in unexpected outcomes in clinical trials. These have included have included cytokines, chemokines, the T cell receptor trimolecular complex, T cells and B cells. The most successful strategies have resulted from a close dialogue between clinical and laboratory work. The key stages in the development of these agents and remaining unanswered questions are reviewed.

An extra dose of rituximab improves clinical response in rheumatoid arthritis patients with initial incomplete B cell depletion: a randomised controlled trial

Objectives Since clinical non-response to 2×1000 mg rituximab has previously been found to be associated with incomplete B cell depletion, we determined, in a randomised controlled proof of concept study, whether patients with initial incomplete B cell depletion would benefit from an additional infusion of rituximab at week 4. Methods Patients with active rheumatoid arthritis despite methotrexate received a first infusion of rituximab 1000 mg and were tested for persistent B cells using highly sensitive flow cytometry on day 15. All received a second infusion of 1 g (according to license), but patients with persistent B cells were subsequently randomised double-blind to receive, 2 weeks later, either a third infusion of 1000 mg rituximab or placebo. Clinical response was determined by European League Against Rheumatism (EULAR) and American College of Rheumatology (ACR) criteria. Results Baseline characteristics were balanced between groups. Treatment with 3×1000 mg rituximab resulted in significantly greater depletion (lower B cell and plasmablast numbers between 8 and 28 weeks) paralleled by significantly better EULAR and ACR20 response rates at 40 weeks (p=0.035 and p=0.027, respectively) and 52 weeks (p=0.021 and p=0.043, respectively) compared with 2×1000 mg. Immunoglobulin titres remained stable in both arms, and adverse event rates were balanced. Conclusions In rituximab-treated patients with incomplete B cell depletion (predictive of poor response), an extra 1000 mg infusion of rituximab at 4 weeks produced both better depletion and clinical responses than placebo with no worsening of safety. Degree of depletion is an important, but modifiable, determinant of response.