Abstract

Objectives. To evaluate the safety and efficacy of low-dose rituximab therapy for refractory thrombocytopenia in patients with SLE.

Methods. Ten adult SLE patients with severe refractory thrombocytopenia (mean platelet count 10.4 × 109/l) were enrolled in this prospective pilot study. All patients had failed traditional high-dose CSs and immunosuppressants including methylprednisolone pulse therapy. Patients were scheduled to receive i.v. rituximab at a dose of 100 mg once weekly for 4 weeks. Previous dose of CSs were gradually tapered, and immunosuppressants were withdrawn. Patients were followed at Weeks 4, 12, 24 and 36.

Results. All patients completed four courses of low-dose rituximab infusion. At Week 4, two (20%) patients achieved complete responses (CRs, platelet count >100 × 109/l). The CR rate increased to 60% (six patients) at Week 12, was maintained at Week 24 and began to drop at Week 36 (four patients, 40%). Overall response (OR, platelet count >50 × 109/l) was achieved in 5/10, 6/10, 7/10 and 5/10 patients at Weeks 4, 12, 24 and 36, respectively. Peripheral CD19+ B cells were depleted (<5 × 106/l) in all patients at Week 4, and gradually increased at Weeks 24 and 36. Serum C3, IgG, IgA and IgM levels did not change significantly (P < 0.05). Infusion reaction was observed in two patients. One patient developed pulmonary thrombosis at Week 14 and active tuberculosis at Week 25.

Conclusions. Low-dose rituximab therapy is effective in treating severe thrombocytopenia in SLE patients who do not respond to vigorous glucocorticoid plus immunosuppressants, and in most cases is safe.

Introduction

Autoimmune thrombocytopenia is a common manifestation of SLE. Rituximab, a chimeric mAb against the mature B-cell surface marker CD20, is an emerging new agent for the treatment of various autoimmune diseases [1–3], including SLE [4–8] and ITP [9, 10]. We and other groups reported that rituximab showed promising efficacy in treating refractory severe thrombocytopenia secondary to CTDs [5, 11]. However, the optimal treatment dosage of rituximab has not been explored. When treating CTD, rheumatologists used to adopt the treatment regimen from that used for B-cell lymphoma (375 mg/m2 once a week for consecutive 4 weeks) [12], though it is well realized that the B-cell load in patients with CTD is much less than that in patients with lymphoma and therefore a lower dosage of rituximab might be sufficient [13, 14]. Zaja et al. [15, 16] investigated the efficacy of lower dose rituximab (100 mg i.v. weekly for 4 weeks) in patients with ITP, and found that it had a similar response rate though the response was often slower. In our study, we performed a prospective clinical trial using low-dose rituximab (100 mg i.v. weekly for 4 weeks) to treat SLE patients with refractory thrombocytopenia.

Methods

Patients

From December 2008 to November 2009, 10 adult SLE inpatients with severe refractory thrombocytopenia at Peking Union Medical College Hospital were enrolled in the study. All patients fulfilled at least four of the 1997 ACR revised criteria for SLE [17]. Patients were excluded if they were pregnant, or had severe LN (urinary protein excretion >1.5 g/24 h or serum creatine >1.5 mg/dl), drug-induced thrombocytopenia, active infections (including Type B and C viral hepatitis) or malignant diseases.

All patients had severe thrombocytopenia (platelet count < 10 × 109/l or <30 × 109/l with bleeding propensity). All patients had failed at least one course of methylprednisolone pulse therapy (1 g/day for 3 consecutive days) and (or) IVIG (20 g/day for 3–5 consecutive days) and high-dose glucocorticoid in combination with immunosuppressants, including CYC (i.v. pulse 1000 mg every month or 100 mg/day orally), vincristine (1–2 mg, weekly) and CSA (3–5 mg/kg/day). One of them had failed recombinant human thrombopoietin (rhTPO) and one case had undergone splenectomy without improvement. The study was approved by the ethics committee of Peking Union Medical College Hospital. Written informed consent was obtained from all patients.

Treatment regimen

Rituximab (Roche, USA) at a dose of 100 mg was administered i.v. once weekly for a total of four infusions (Days 1, 8, 15 and 22) [15]. Intravenous CSs were not administered at the time of the rituximab infusions.

Previous doses of oral prednisone or prednisolone were continued and gradually tapered to minimal maintenance dose (prednisone ≤7.5 mg/day). All previous immunosuppressants were withdrawn. Patients were followed at Weeks 4, 12, 24 and 36 after the start of the first dose of rituximab.

Laboratory studies

Laboratory evaluation included: complete haemogram, serum chemistry profiles, ANAs (IIF test), anti-dsDNA antibody (IFF and ELISA tests), anti-ENA antibodies (ID and immunoblot tests) and aCL, anti-β2-glycoprotein-I (anti-β2-GP-I) antibody (ELISA test), LA (DRVVT test), direct and indirect Coombs test, lymphocyte subsets (CD19+ B cells, CD16+CD56+ NK cells, CD3+CD4+ Th cells and CD3+CD8+ Tc cells) and serum immunoglobulin (IgG, IgA and IgM) and complement levels.

Response criteria

Response criteria were defined as follow [9].

  • Complete response (CR): a rise in platelet count to >100 × 109/l.

  • Partial response (PR): a rise in platelet count to between 50 and 100 × 109/l.

  • No response (NR): those patients who did not have CR or PR.

  • Overall response (OR): patients with CR or PR.

Statistical analysis

Standard descriptive summary statistics on all parameters were carried out with SPSS software version 13.0 (SPSS, Chicago, IL, USA), including arithmetic mean, s.d., minimum value, lower quartile, median, upper quartile and maximum value. Wilcoxon signed-rank test was used for comparing parameters before treatment with those after treatment.

Results

The clinical and laboratory characteristics of the patients are summarized in Table 1. All patients were female, age ranged from 20 to 42 years [34.3 (9.5)], SLE disease duration 0.5–20 years [4.5 years; interquartile range (IQR), 1.4–7 years], duration of thrombocytopenia 0.5–10 years (1 year; IQR, 1–5 years) and the mean platelet count at baseline was 10.4 × 109/l (range 4–23 × 109/l). All patients completed four courses of low-dose rituximab infusion. At Week 4, two (20%) patients achieved CR. The CR rate increased to 60% (six patients) at Week 12, was maintained at Week 24 and began to drop at Week 36 (four patients, 40%). ORs were achieved in 5/10, 6/10, 7/10 and 5/10 patients at Weeks 4, 12, 24 and 36, respectively (Fig. 1A and B). The disease activity measured by SLEDAI [18] was markedly decreased in most patients (Table 1).

Fig. 1

Platelet response and monitoring of laboratory parameters. (A) Each column represents response rate at a particular time point. Case 3 was lost to follow-up at Week 14 and was considered as NR at Weeks 24 and 36. (B) Platelet counts. (C) CD19+ B-cell counts. (D) Complement C3 level. (B and C) The central horizontal bold line is the median; the lower and upper box limits are the first and third quartiles, respectively. The whiskers extend to the most extreme data points. (D) Data are presented as mean (s.d.). Normal values are: CD19+ B cells, 180–350 × 106/l; C3, 0.60–1.50 g/l.

Table 1

Basic characteristics, treatment response and adverse events of patients

Case no.SexAge, yearsDuration of SLE, yearsDuration of thrombocytopenia, yearsMedical historyAuto-antibodiesSLEDAI
Platelet count, ×109/l
Adverse events
Week 0Week 24Week 0Week 4Week 12Week 24Week 36
40 Oral ulcers, arthritis, neurological disorder ANA, anti-U1RNP, anti-β2-GP-I 11 34 25 102 16 None 
40 Malar rash, oral ulcers ANA, anti- SSA, LA 95 108 132 158 PE, TB 
42 20 Arthritis, neurological disorder ANA, anti-dsDNA, anti-U1RNP 12 N/A 11 14 11 N/A N/A None 
28 Oral ulcers, arthritis ANA, aCL 11 30 14 10 22 None 
31 0.5 0.5 Oral ulcers, arthritis ANA, anti-U1RNP 14 63 171 186 215 None 
29 0.5 0.5 Photosensitivity, oral ulcers ANA, anti-SSA 75 106 193 144 None 
53 10 10 Nephritis, arthritis ANA, anti-U1RNP 10 26 119 44 39 Infusion reaction 
20 Malar rash, oral ulcers ANA, anti-rRNP 11 22 43 57 35 None 
33 2.5 Serositis, oral ulcers ANA, anti-β2-GP-I, anti-dsDNA, anti-SSA 157 120 121 92 None 
10 27 Malar rash, arthritis ANA, anti-SSA 23 135 193 143 136 Infusion reaction 
Case no.SexAge, yearsDuration of SLE, yearsDuration of thrombocytopenia, yearsMedical historyAuto-antibodiesSLEDAI
Platelet count, ×109/l
Adverse events
Week 0Week 24Week 0Week 4Week 12Week 24Week 36
40 Oral ulcers, arthritis, neurological disorder ANA, anti-U1RNP, anti-β2-GP-I 11 34 25 102 16 None 
40 Malar rash, oral ulcers ANA, anti- SSA, LA 95 108 132 158 PE, TB 
42 20 Arthritis, neurological disorder ANA, anti-dsDNA, anti-U1RNP 12 N/A 11 14 11 N/A N/A None 
28 Oral ulcers, arthritis ANA, aCL 11 30 14 10 22 None 
31 0.5 0.5 Oral ulcers, arthritis ANA, anti-U1RNP 14 63 171 186 215 None 
29 0.5 0.5 Photosensitivity, oral ulcers ANA, anti-SSA 75 106 193 144 None 
53 10 10 Nephritis, arthritis ANA, anti-U1RNP 10 26 119 44 39 Infusion reaction 
20 Malar rash, oral ulcers ANA, anti-rRNP 11 22 43 57 35 None 
33 2.5 Serositis, oral ulcers ANA, anti-β2-GP-I, anti-dsDNA, anti-SSA 157 120 121 92 None 
10 27 Malar rash, arthritis ANA, anti-SSA 23 135 193 143 136 Infusion reaction 

PE: pulmonary embolism; TB: tuberculosis; F: female.

Table 1

Basic characteristics, treatment response and adverse events of patients

Case no.SexAge, yearsDuration of SLE, yearsDuration of thrombocytopenia, yearsMedical historyAuto-antibodiesSLEDAI
Platelet count, ×109/l
Adverse events
Week 0Week 24Week 0Week 4Week 12Week 24Week 36
40 Oral ulcers, arthritis, neurological disorder ANA, anti-U1RNP, anti-β2-GP-I 11 34 25 102 16 None 
40 Malar rash, oral ulcers ANA, anti- SSA, LA 95 108 132 158 PE, TB 
42 20 Arthritis, neurological disorder ANA, anti-dsDNA, anti-U1RNP 12 N/A 11 14 11 N/A N/A None 
28 Oral ulcers, arthritis ANA, aCL 11 30 14 10 22 None 
31 0.5 0.5 Oral ulcers, arthritis ANA, anti-U1RNP 14 63 171 186 215 None 
29 0.5 0.5 Photosensitivity, oral ulcers ANA, anti-SSA 75 106 193 144 None 
53 10 10 Nephritis, arthritis ANA, anti-U1RNP 10 26 119 44 39 Infusion reaction 
20 Malar rash, oral ulcers ANA, anti-rRNP 11 22 43 57 35 None 
33 2.5 Serositis, oral ulcers ANA, anti-β2-GP-I, anti-dsDNA, anti-SSA 157 120 121 92 None 
10 27 Malar rash, arthritis ANA, anti-SSA 23 135 193 143 136 Infusion reaction 
Case no.SexAge, yearsDuration of SLE, yearsDuration of thrombocytopenia, yearsMedical historyAuto-antibodiesSLEDAI
Platelet count, ×109/l
Adverse events
Week 0Week 24Week 0Week 4Week 12Week 24Week 36
40 Oral ulcers, arthritis, neurological disorder ANA, anti-U1RNP, anti-β2-GP-I 11 34 25 102 16 None 
40 Malar rash, oral ulcers ANA, anti- SSA, LA 95 108 132 158 PE, TB 
42 20 Arthritis, neurological disorder ANA, anti-dsDNA, anti-U1RNP 12 N/A 11 14 11 N/A N/A None 
28 Oral ulcers, arthritis ANA, aCL 11 30 14 10 22 None 
31 0.5 0.5 Oral ulcers, arthritis ANA, anti-U1RNP 14 63 171 186 215 None 
29 0.5 0.5 Photosensitivity, oral ulcers ANA, anti-SSA 75 106 193 144 None 
53 10 10 Nephritis, arthritis ANA, anti-U1RNP 10 26 119 44 39 Infusion reaction 
20 Malar rash, oral ulcers ANA, anti-rRNP 11 22 43 57 35 None 
33 2.5 Serositis, oral ulcers ANA, anti-β2-GP-I, anti-dsDNA, anti-SSA 157 120 121 92 None 
10 27 Malar rash, arthritis ANA, anti-SSA 23 135 193 143 136 Infusion reaction 

PE: pulmonary embolism; TB: tuberculosis; F: female.

Monitoring of laboratory parameters

Peripheral CD19+ B cells, with a median baseline count of 226 × 106/l (range, 72–496 × 106/l), all dropped to depleted level (defined as <5 × 106/l) at Week 4, and remained at the depleted level in most patients (8/10, 80%) at Week 12, and gradually increased at Week 24 (7 × 106/l, IQR 6–42 × 106/l) and Week 36 (57 × 106/l, IQR 44–189 × 106/l) (Fig. 1C). Peripheral blood CD3+CD4+ Th cells, CD3+CD8+ cytotoxic T cells (Tc) cells, as well as CD16+CD56+ NK cells, remained stable throughout the study.

Serum C3 level was slightly increased (Fig. 1D), and serum immunoglobulin G (IgG), immunoglobulin A (IgA) and immunoglobulin M (IgM) levels were slightly decreased, but the changes did not reach statistical difference. Four out of 10 patients presented aPLs (Table 1). The titre of aCL and LA remained stable, while the titre of anti-β2-GP-I antibody decreased significantly after treatment.

Adverse events

Two patients (Cases 6 and 10) experienced mild infusion reaction during the first infusion. The reaction disappeared after adjustment of infusion rate. One patient (Case 2) developed pulmonary thrombosis at Week 14 and active tuberculosis at Week 25, and symptoms improved with anti-coagulant and anti-tuberculosis treatments. No viral or fungal infections were observed in these patients.

Discussion

In our prospective cohort study, low-dose rituximab was administered in 10 SLE patients with severe thrombocytopenia who did not respond to traditional treatment including methylprednisolone pulse therapy. The study found that 80% of the patients responded to low-dose rituximab, and the response could be as early as Week 4, in line with the depletion time of B cells. The mechanism of rituximab in treating autoimmune thrombocytopenia remains unclear. Rituximab depletes B cell and inhibits some B-cell pathologic functions, including autoantibody production, antigen presenting and cytokine secretion. B-cell depletion by rituximab may also revert the Th1/Th2 ratio as well as expression of Fas ligand, Bcl-2, Bax in Th cells in patients with ITP [19]. In our study, the response could be maintained throughout 24 weeks, despite concomitant glucocorticoids being gradually tapered, and patients discontinuing previous immunosuppressants. When followed at Week 36, thrombocytopenia began to flare in two patients, requiring retreatment with rituximab. Due to the small number in the study, it was impossible to extrapolate which parameter could be used to predict patient response, though as shown in Table 1, patients with longer duration of thrombocytopenia (>5 years) seem to respond less well to rituximab treatment.

It is not surprising to find that with the low-dose regimen, infusion reaction were rare and did not require discontinuation of treatment. During follow-up, one patient had active tuberculosis at Week 25. Despite the fact that it might not be justified to ascribe the tuberculosis episode solely to low-dose rituximab, as the patient had a very long history of SLE (20 years), and had been vigorously treated with glucocorticoid and immunosuppressants, we suggest cautious tuberculosis screening before rituximab treatment, because low-dose rituximab could also potently deplete B cells.

In our study, four patients had aPLs. Though thrombocytopenia in three of them responded to rituximab treatment, one patient developed thrombosis 14 weeks after the treatment. Suzuki et al. [20] reported two cases of thrombotic exacerbation in lupus patients with APS after retreatment with rituximab. Our study also suggests that in lupus patients with APS, though rituximab is an effective treatment for thrombocytopenia, it cannot effectively prevent patients from developing thromboembolism.

In conclusion, our study shows that low-dose rituximab therapy is promising in treating severe thrombocytopenia in SLE patients. A randomized, comparative study with standard and low-dose rituximab is warranted. In view of the paucity of effective treatment options and cost-effectiveness, low-dose rituximab should be considered in SLE patients with severe thrombocytopenia that do not respond to vigorous glucocorticoid plus immunosuppressants.

graphic

Acknowledgements

Funding: This work was supported by National Key Technology R&D Program (2008BAI59B03, 2008BAI59B02), New Century Excellent Talents Project, Ministry of Education of China (NCET04-0191), National Natural Science Foundation of China (30400410, 30972731) and National Program for Key Basic Research Project (2007CB512405 for Immunology), Ministry of Science and Technology, China.

Disclosure statement: The authors have declared no conflicts of interest.

References

1
Emery
P
Fleischmann
R
Filipowicz-Sosnowska
A
, et al. 
The efficacy and safety of rituximab in patients with active rheumatoid arthritis despite methotrexate treatment: results of a phase IIB randomized, double-blind, placebo-controlled, dose-ranging trial
Arthritis Rheum
2006
, vol. 
54
 (pg. 
1390
-
400
)
2
Hauser
SL
Waubant
E
Arnold
DL
, et al. 
B-cell depletion with rituximab in relapsing-remitting multiple sclerosis
N Engl J Med
2008
, vol. 
358
 (pg. 
676
-
88
)
3
Jones
RB
Tervaert
JWC
Hauser
T
, et al. 
Rituximab versus cyclophosphamide in ANCA-associated renal vasculitis
N Engl J Med
2010
, vol. 
363
 (pg. 
211
-
20
)
4
Kumar
S
Benseler
SM
Kirby-Allen
M
Silverman
ED
B-cell depletion for autoimmune thrombocytopenia and autoimmune hemolytic anemia in pediatric systemic lupus erythematosus
Pediatrics
2009
, vol. 
123
 (pg. 
e159
-
63
)
5
Lee
JW
Kim
HA
Sung
JM
Suh
CH
Successful treatment of refractory immune thrombocytopenia with anti-CD20 antibody in a patient with systemic lupus erythematosus
Lupus
2010
, vol. 
19
 (pg. 
227
-
8
)
6
Limal
N
Cacoub
P
Sène
D
Guichard
I
Piette
JC
Rituximab for the treatment of thrombotic thrombocytopenic purpura in systemic lupus erythematosus
Lupus
2008
, vol. 
17
 (pg. 
69
-
71
)
7
Looney
RJ
Anolik
JH
Campbell
D
, et al. 
B cell depletion as a novel treatment for systemic lupus erythematosus: a phase I/II dose-escalation trial of rituximab
Arthritis Rheum
2004
, vol. 
50
 (pg. 
2580
-
9
)
8
Terrier
B
Amoura
Z
Ravaud
P
, et al. 
Safety and efficacy of rituximab in systemic lupus erythematosus: results from 136 patients from the French autoimmunity and rituximab registry
Arthritis Rheum
2010
, vol. 
62
 (pg. 
2458
-
66
)
9
Garcia-Chavez
J
Majluf-Cruz
A
Montiel-Cervantes
L
Esparza
MG-R
Vela-Ojeda
J
Rituximab therapy for chronic and refractory immune thrombocytopenic purpura: a long-term follow-up analysis
Ann Hematol
2007
, vol. 
86
 (pg. 
871
-
7
)
10
Stasi
R
Pagano
A
Stipa
E
Amadori
S
Rituximab chimeric anti-CD20 monoclonal antibody treatment for adults with chronic idiopathic thrombocytopenic purpura
Blood
2001
, vol. 
98
 (pg. 
952
-
7
)
11
Zheng
WJ
Zhang
X
Wang
Q
Xu
D
Zeng
XF
Zhang
FC
Refractory severe connective tissue disease thrombocytopenia: is rituximab treatment effective and safe?
Ann Rheum Dis
2009
, vol. 
68
 (pg. 
1077
-
8
)
12
Maloney
DG
Grillo-Lopez
AJ
White
CA
, et al. 
IDEC-C2B8 (rituximab) anti-CD20 monoclonal antibody therapy in patients with relapsed low-grade non-Hodgkin's lymphoma
Blood
1997
, vol. 
90
 (pg. 
2188
-
95
)
13
Provan
D
Butler
T
Evangelista
ML
Amadori
S
Newland
AC
Stasi
R
Activity and safety profile of low-dose rituximab for the treatment of autoimmune cytopenias in adults
Haematologica
2007
, vol. 
92
 (pg. 
1695
-
8
)
14
von Bonin
M
Oelschlägel
U
Radke
J
, et al. 
Treatment of chronic steroid-refractory graft-versus-host disease with low-dose rituximab
Transplantation
2008
, vol. 
86
 (pg. 
875
-
9
)
15
Zaja
F
Battista
ML
Pirrotta
MT
, et al. 
Lower dose rituximab is active in adults patients with idiopathic thrombocytopenic purpura
Haematologica
2008
, vol. 
93
 (pg. 
930
-
3
)
16
Zaja
F
Vianelli
N
Volpetti
S
, et al. 
Low-dose rituximab in adult patients with primary immune thrombocytopenia
Eur J Haematol
2010
, vol. 
85
 (pg. 
329
-
34
)
17
Hochberg
MC
Updating the American College of Rheumatology revised criteria for the classification of systemic lupus erythematosus
Arthritis Rheum
1997
, vol. 
40
 pg. 
1725
 
18
Bombardier
C
Gladman
DD
Urowitz
MB
Caron
D
Chang
CH
Derivation of the SLEDAI. A disease activity index for lupus patients. The Committee on Prognosis Studies in SLE
Arthritis Rheum
1992
, vol. 
35
 (pg. 
630
-
40
)
19
Stasi
R
Del Poeta
G
Stipa
E
, et al. 
Response to B-cell depleting therapy with rituximab reverts the abnormalities of T-cell subsets in patients with idiopathic thrombocytopenic purpura
Blood
2007
, vol. 
110
 (pg. 
2924
-
30
)
20
Suzuki
K
Nagasawa
H
Kameda
H
, et al. 
Severe acute thrombotic exacerbation in two cases with anti-phospholipid syndrome after retreatment with rituximab in phase I/II clinical trial for refractory systemic lupus erythematosus
Rheumatology
2009
, vol. 
48
 (pg. 
198
-
9
)

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