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Background The combination of multiple cycles of rituximab and intravenous immune globulins has been reported to be effective in patients with severe pemphigus. The aim of this study was to assess the efficacy of a single cycle of rituximab in severe types of pemphigus.
Methods We studied 21 patients with pemphigus whose disease had not responded to an 8-week course of 1.5 mg of prednisone per kilogram of body weight per day (corticosteroid-refractory disease), who had had at least two relapses despite doses of prednisone higher than 20 mg per day (corticosteroid-dependent disease), or who had severe contraindications to corticosteroids. The patients were treated with four weekly infusions of 375 mg of rituximab per square meter of body-surface area. The primary end point was complete remission 3 months after the end of rituximab treatment; complete remission was defined as epithelialization of all skin and mucosal lesions.
Results Eighteen of 21 patients (86%; 95% confidence interval, 64 to 97%) had a complete remission at 3 months. The disease relapsed in nine patients after a mean of 18.9±7.9 months. After a median follow-up of 34 months, 18 patients (86%) were free of disease, including 8 who were not receiving corticosteroids; the mean prednisone dose decreased from 94.0±10.2 to 12.0±7.5 mg per day (P=0.04) in patients with corticosteroid-refractory disease and from 29.1±12.4 to 10.9±16.5 mg per day (P=0.007) in patients with corticosteroid-dependent disease. Pyelonephritis developed in one patient 12 months after rituximab treatment, and one patient died of septicemia 18 months after rituximab treatment. These patients had a profound decrease in the number of circulating B lymphocytes but normal serum levels of IgG.
Conclusions A single cycle of rituximab is an effective treatment for pemphigus. Because of its potentially severe side effects, its use should be limited to the most severe types of the disease. (ClinicalTrials.gov number, NCT00213512
[ClinicalTrials.gov]
.)
Rituximab, a monoclonal antibody directed against the CD20 antigen of B lymphocytes, has been demonstrated to be effective in various autoimmune diseases6,7,8,9,10,11,12 and in occasional cases of life-threatening pemphigus.13,14,15,16,17,18,19,20,21,22 Recently, the combination of multiple cycles of rituximab and intravenous immune globulin, another potentially active agent in pemphigus, was reported to be effective in a single-center study of 11 patients with pemphigus.23 We report a multicenter series of 21 patients with severe pemphigus treated by a simple regimen of one cycle of rituximab. Immunologic evaluations explored the mechanism of the short-term and long-term effects of rituximab on these patients.
Methods
Patients
Thirteen centers in France participated in this prospective, open trial. The study was approved by the ethics committee of Seine-Maritime, and written informed consent was obtained from each patient.
Consecutive patients with severe mucosal erosions, superficial blisters, or both suggestive of pemphigus vulgaris or pemphigus foliaceus; a histologic picture of intraepidermal acantholysis; and deposition of IgG, complement component 3 (C3), or both on the keratinocyte membrane detected by direct immunofluorescence24 were included if additional criteria were met. These were the absence of response to an 8-week course of treatment with 1.5 mg of prednisone per kilogram of body weight per day (corticosteroid-refractory cases); the occurrence of at least two cutaneous or mucosal relapses during the period when corticosteroid doses were being decreased, despite prednisone doses higher than 20 mg per day (corticosteroid-dependent cases); and contraindication to corticosteroids because of severe associated medical conditions.
Treatment
The patients were treated with one cycle of four weekly infusions of rituximab at a dose of 375 mg per square meter of body-surface area on days 1, 8, 15, and 22. Corticosteroids were maintained at the initial dose until the disease was controlled, and the corticosteroid dose was then reduced by 10% twice a month. Patients with contraindications to corticosteroids were treated with rituximab alone. Complete remission was defined as the epithelialization of all skin and mucosal lesions, partial remission as the epithelialization of more than 50% of lesions but not of all lesions, and relapse as the occurrence of new cutaneous or mucosal erosions.
End Points
The patients were evaluated clinically and biologically every month during the first year of follow-up and every other month during the second year. The primary end point was the rate of complete remission 3 months after the last infusion of rituximab. The secondary end points were the rate of complete remission during the study period, the time from the start of rituximab treatment to complete remission, the number of relapses and the length of time to each relapse, and adverse effects of treatment.
Immunologic Evaluation
Blood samples were collected at each evaluation. Titers of antibodies against desmoglein 1 and desmoglein 3 were measured by a desmoglein enzyme-linked immunosorbent assay (ELISA) test (MESACUP Desmoglein Test, MBL Medical and Biological Laboratories) with 1:100 diluted serum. For determination of IgG subclass, mouse antihuman IgG1, IgG2, IgG3, and IgG4 antibodies (Sigma) and peroxidase-conjugated goat antimouse IgG (Rockland) were used. IgG reactivity of pemphigus vulgaris serum against the NH2 terminal domains of desmoglein 3 was characterized with the use of ELISA with baculovirus-derived recombinant proteins of desmoglein 3.25
The phenotype of peripheral-blood mononuclear cells was determined by three-color flow cytometry with the use of murine monoclonal antibodies against CD3, CD4, CD5, CD19, CD20, CD21, CD22, CD23, CD24, CD27, CD38, CD56, and CD86 (Coulter). The IgG, IgA, and IgM repertoire of peripheral-blood B lymphocytes was determined with the use of the immunoscope technique, a method that evaluates the diversity of the B-lymphocyte repertoire and monitors its evolution. First, a polymerase chain reaction amplified the heavy-chain variable (HV) region of the IgG, IgA, and IgM molecules. In a second step, the lengths of the complementary determining region 3 (CDR3) were analyzed on an automatic sequencer.26 The serum levels of antibodies against pneumococcal capsule polysaccharide and tetanus toxin were determined on days 0, 90, and 180.27
Statistical Analysis
Two-sided P values less than 0.05 were considered to indicate statistical significance. Continuous variables are expressed as means ±SD. Mean doses of prednisone were compared with the use of the nonparametric Wilcoxon test. Roche, France (the maker of rituximab) had no role in the design of the study, in data accrual or analysis, or in manuscript preparation.
Results
Characteristics of the Patients
Twenty-one patients (14 men and 7 women; 14 with pemphigus vulgaris and 7 with pemphigus foliaceus) were enrolled between January 2003 and December 2004 and followed through March 2007. Their mean (±SD) age was 53.7±15.6 years. The baseline clinical characteristics of the patients are shown in Table 1. The mean proportion of the body-surface area involved was 27%. All the patients had severe oral involvement and weight loss of up to 10 kg. In addition, seven patients had severe involvement of one or more other mucosae, including the genital, anal, conjunctival, or pharyngeal mucosae or a combination of these. All patients with corticosteroid-refractory disease and all patients with corticosteroid-dependent disease had been treated previously with various immunosuppressive drugs, intravenous immune globulins, or both without success. The duration of all systemic therapy before study entry ranged from 4 to 168 months (mean, 70.2). Severe associated medical conditions or side effects of corticosteroids were present at baseline in 14 patients (67%). Five patients were treated with rituximab alone because they had contraindications to corticosteroid use. Corticosteroids were contraindicated in two patients because of severe diabetes mellitus, arterial hypertension, or both; in two patients because of a history of severe infection, osteonecrosis of the hip, or both; and in one patient because of old age (84 years) and poor general condition (Table 1).
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Eighteen of 21 patients (86%; 95% confidence interval, 64 to 94) had a complete remission at 3 months, including 12 of 14 patients with pemphigus vulgaris and 6 of 7 with pemphigus foliaceus (Table 2). Two patients with pemphigus vulgaris had a delayed complete remission on days 180 and 360 (Figure 1). One patient with pemphigus foliaceus with lesions that initially involved the entire body surface was only slightly improved after rituximab, and treatment of this patient was considered to have failed. All the other patients (95%) had a complete remission at some time during the study period. The median delays to partial and complete remission are shown in Table 3.
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The mean dose of prednisone for patients with corticosteroid-refractory disease decreased from 94.0±10.2 mg per day at baseline to 12.0±7.5 mg per day at the end of the study (P=0.04) (Figure 1). The mean dose of prednisone for patients with corticosteroid-dependent disease decreased from 29.1±12.4 mg per day at baseline to 10.9±16.5 mg per day at the end of the study (P=0.007). Nine patients reported minor and transient side effects during rituximab infusion: headache in three patients, asthenia in three, fever in one, chills in one, and nausea in one. In addition, two severe side effects were observed: one patient had pyelonephritis 12 months after rituximab treatment, and one patient died from septicemia 18 months after rituximab treatment. The patient who died also had rheumatoid arthritis and was concomitantly treated with the anti–tumor necrosis factor agent etanercept.
Immunologic Evaluations
Peripheral-blood B- and T-lymphocyte subpopulations and T-lymphocyte cytokine production were analyzed longitudinally. The B-cell count decreased dramatically from a median of 275 cells per cubic millimeter (range, 29 to 752) to 0 cells per cubic millimeter (range, 0 to 1) at day 21 and remained undetectable until day 180 in all but two patients. Reappearance of B cells began between day 180 and day 270. Ninety percent of them expressed a CD19+CD27– phenotype suggestive of naive B lymphocytes. Twenty-nine percent had a CD19+ CD38highCD24high transitional phenotype suggestive of the migration of B cells from the bone marrow to the periphery. No major changes in T cells or natural killer cells or in T-cell cytokine production were detected after rituximab treatment.
Using the immunoscope method, we followed the evolution of the repertoire of IgG, IgA, and IgM in blood B lymphocytes in two patients. Before treatment, immunoscope profiles showed some peak expansions in the immunoglobulin HV-region genes (IgVH3a, IgVH3b, and IgVH4), the most represented ones, reflecting in vivo antigen-driven responses. Six months later, reappearing blood B cells showed a typical gaussian distribution of the CDR3 lengths for these IgVH families, similar to that found in the naive B cells of cord blood, suggesting the reconstitution of a diverse B-cell repertoire (data not shown).
Antidesmoglein autoantibody response was then analyzed. A dramatic decrease of IgG and IgG4 anti–desmoglein 1 and anti–desmoglein 3 antibodies was observed in 15 of the 18 patients who had a complete remission 3 months after rituximab treatment, whereas persistent high titers were detected in the 2 patients who had a delayed complete remission and in the 1 patient in whom treatment failed. Persistent high titers or rises in anti–desmoglein 1 and anti–desmoglein 3 antibody levels were detected in patients with relapsing disease and, surprisingly, in five patients with pemphigus vulgaris in whom a complete remission was maintained (Figure 1). To disentangle this discrepancy, we retested serum from these patients on recombinant proteins of five extracellular (EC) domains of desmoglein 3 (EC1 to EC5). Antibodies reacting with epitopes of the EC1 to EC2 domains, which are considered the main pathogenic antibodies,28,29 decreased dramatically after rituximab treatment and remained undetectable until day 540, a result that was in accordance with the absence of mucosal lesions in these patients.30,31
Finally, to assess the influence of rituximab on antimicrobial response, we first determined the serum level of IgG and IgM antibodies. No significant change in mean IgG levels was observed after rituximab treatment (P=0.79). On the contrary, mean IgM levels decreased from 1.5±1.1 g per liter at baseline to 1.1±0.9 g per liter on day 180 and 1.0±0.7 g per liter on day 360 (P=0.003). We then determined that the levels of antibodies against pneumococcal capsule polysaccharide and the levels of antibodies against tetanus toxin were not significantly altered between baseline, day 21, and day 90. The two patients who had severe infections, one at 12 months after rituximab treatment and one at 18 months, had normal serum IgG levels (21 g per liter and 13.5 g per liter, respectively), despite low numbers of circulating B lymphocytes (5 per cubic millimeter and 9 per cubic millimeter, respectively) at the times of their infections.
Discussion
Our study demonstrated the efficacy of rituximab for severe pemphigus; 86% of patients were in complete remission 3 months after receiving four weekly infusions of rituximab. After a 34-month follow-up period, 18 patients were free of disease, and 8 of these patients were not receiving any systemic therapy. Overall, treatment with rituximab both resulted in major clinical improvement and permitted a large decrease in the doses of corticosteroids. Our results were similar to those recently reported by Ahmed et al.,23 who obtained a complete remission in 9 of 11 patients (82%). Our patients were treated with one cycle of four weekly infusions of rituximab, and the patients in the study by Ahmed et al. were treated with two induction cycles of rituximab, followed by consolidation therapy and six infusions of intravenous immune globulins, another potentially active agent in pemphigus.23,32,33 Therefore, we believe multiple cycles of rituximab may not be necessary. Accordingly, we suggest restricting the use of additional cycles of rituximab to the few relapses that cannot be adequately controlled with conventional treatments.
Two severe side effects were observed in our study: pyelonephritis developed in one patient 12 months after rituximab treatment, and one patient died from septicemia 18 months after rituximab treatment. It is important to emphasize that rituximab treatment is associated with a risk of death from severe side effects, such as pneumocystis infection, toxic epidermal necrolysis, and progressive multifocal leukoencephalopathy.34,35 The risk of serious infection led Ahmed et al. to propose combining intravenous immune globulins with rituximab during the first 6 months of treatment with rituximab.23 We do not think that 6 months of treatment with immune globulins would have prevented the two serious infections observed in our study, which occurred at 12 and 18 months in patients who had no defect in IgG serum levels or in preformed antibacterial antibodies. It is not known whether the addition of intravenous immune globulins to rituximab reduces the risk of serious infections.36,37
Immunologic investigations demonstrated that one cycle of rituximab induced a prolonged depletion of peripheral-blood B lymphocytes, followed by the reappearance of B cells with a naive phenotype similar to that found in cord blood from neonates. Rituximab induced a modification of the repertoire of B cells, with the disappearance of the initially expanded populations and the reconstitution of a diverse B-cell repertoire that might account for its long-lasting effect.
The clinical response to rituximab in patients with pemphigus foliaceus was closely related to the evolution of anti–desmoglein 1 antibodies, which dramatically decreased in patients who had a complete remission, whereas we were surprised to observe persistently high levels of anti–desmoglein 3 antibodies in a few patients in whom pemphigus vulgaris was in complete remission. The dissociation between anti–desmoglein 1 and anti–desmoglein 3 antibody responses, as well as the absence of major modification of serum levels of antibodies against pneumococcal and tetanus-toxin antigens, suggested some specificity of rituximab for the autoreactive B-cell response.38,39 One hypothesis is that rituximab would differentially affect the turnover of short-life and long-life plasma cells that produce antibodies directed against desmoglein 1 and desmoglein 3.40
Overall, our study suggests that rituximab is a very effective treatment for severe pemphigus. Larger series with a longer follow-up are needed to assess the long-term risks of this treatment.
Supported by the French Society of Dermatology, Paris, and by Roche, France.
Presented in part at the December 2006 Congress of the French Society of Dermatology and at the September 2006 Congress of the European Society of Dermatological Research (ESDR), both in Paris.
No potential conflict of interest relevant to this article was reported.
We thank Marie-France Hellot for her help with the statistical analysis, Vincent Ferranti for monitoring the study, Ken Wood for assistance in editing an earlier version of the manuscript, and Nathalie Jourdain for excellent secretarial assistance.
Source Information
From Rouen University Hospital, Rouen (P.J., P.M.); INSERM Unité 519, Rouen University Hospital, Rouen (P.J., H.M., D.G., S.J., F.T., P.M.); Henri Mondor University Hospital, Créteil (J.-C.R.); Clermont-Ferrand University Hospital, Clermont-Ferrand (M.D.); Pasteur Institute, Paris (M.-L.G.); Limoges University Hospital, Limoges (C.B.); Nantes University Hospital, Nantes (B.D.); Bordeaux University Hospital, Bordeaux (M.-S.D.); Lille University Hospital, Lille (E.D.); Poissy–Saint Germain-en-Laye Intercommunal Hospital, Saint Germain-en-Laye (C. Pauwels); Paris V University, Paris (N.F.); Paris XIII University Hospital, Bobigny (F.C.); Bichat University Hospital, Paris (C. Picard); Paris X University Hospital, Paris (E.T.-B.); and Reims University Hospital, Reims (P.B.) — all in France; and the Faculty of Medicine, Philipp University, Marburg, Germany (R.M., M.H.).
Address reprint requests to Dr. Joly at the Clinique Dermatologique, Hôpital Charles Nicolle, 1 rue de Germont, 76031 Rouen CEDEX, France, or at Pascal.Joly{at}chu-rouen.fr.
References
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