Review Article. Cyclophosphamide in Lupus Nephritis. Introduction. Mechanisms of Action of CYC. Chi-Chiu Mok

Transcription

1 Review Article Cyclophosphamide in Lupus Nephritis Chi-Chiu Mok Abstract: Keywords: Cyclophosphamide (CYC) remains the initial treatment of choice for severe lupus nephritis. However, the optimal route, dosage and duration of CYC treatment is not known. While a lower dose and shorter course of CYC may limit toxicities, its long term efficacy as compared to conventional CYC regimens is unconfirmed. Renal flares are common upon CYC discontinuation and maintenance therapy is necessary. For patients with recalcitrant disease, combination strategies consisting of CYC and other modalities such as the nucleoside analogues, apheresis and the biological response modifiers may be beneficial. Immunoablative high-dose CYC, with and without stem cell rescue, has shown preliminary success in refractory lupus nephritis. Alternative options of treatment may also be considered for patients who are recalcitrant or intolerant to CYC. Cytotoxic, glomerulonephritis, immunosuppressive, toxicities Introduction Renal disease in systemic lupus erythematosus (SLE) carries significant mortality and morbidity. Of the various histological classes, diffuse proliferative glomerulonephritis (DPGN) (WHO class IV) carries the worst prognosis, with 11-48% of patients resulting in end stage renal disease at 5 years. 1-6 Focal proliferative glomerulonephritis (WHO class III) with 50% or more of glomeruli involved shares similar prognosis with DPGN and should be treated with equal vigor. 7,8 Pure membranous lupus nephropathy (WHO class V), on the other hand, has a variable prognosis. 9 Aggressive treatment is warranted for patients with deteriorating renal function or severe/ persistent nephrotic syndrome. Cyclophosphamide (CYC), given either orally or as intermittent pulses together with corticosteroid, has been evaluated in randomized controlled trials at the National Institutes of Health (NIH) These studies consistently demonstrated that CYC-containing regimens were superior to steroid alone in the preservation of renal function in severe proliferative lupus nephritis. However, the optimal route, dose and duration of CYC treatment is still uncertain. Both the efficacy and toxicities of CYC appear to be dose-related Although a lower dose and shorter course of CYC may limit toxicities, 18 its long term efficacy when compared to standard CYC regimens remains to be established. Renal flares are common after discontinuation of CYC 19 and maintenance therapy is recommended. Immunoablative high-dose CYC, with and without stem cell rescue, and combination of CYC with other modalities such as the nucleoside analogues, plasmapheresis and the monoclonal antibodies are being explored for refractory lupus. Alternative treatment modalities of treatment may also be considered for patients who are recalcitrant or intolerant to CYC. In this article, the current data on the use of CYC in severe lupus nephritis is being reviewed. DEPARTMENT OF MEDICINE, TUEN MUN HOSPITAL, TSING CHUNG KOON ROAD, TUEN MUN, N.T., HONG KONG SAR Chi-Chiu Mok MD, MRCP Correspondence to: Chi-Chiu Mok Mechanisms of Action of CYC CYC is a pro-drug that requires metabolism by the hepatic cytochrome P450 oxidase system to the active compounds 4-dydroxycyclophosphamide and aldophosphamide, which 1

2 CYC IN SEVERE LUPUS NEPHRITIS are cleaved non-enzymatically into phosphoramide mustard and acrolein. 20 Phosphoramide mustard is responsible for the therapeutic actions of CYC while acrolein contributes to bladder toxicities. CYC produces a dose dependent lymphopenia in human subjects and causes an alteration in lymphocyte subsets. 21 In patients with SLE, intermittent monthly pulse CYC induced a reduction of B-lymphocytes, as well as the CD4+ and CD8+ T-lymphocyte subsets. 22 B-lymphocyte number showed a more rapid recovery at completion of treatment but persistent reduction was observed in the T-lymphocyte subsets, which also showed a diminished proliferative responses to mitogenic stimulation. Moreover, CYC has also been shown to modulate T-cell activation responses and inhibit B-cell antibody production. 23,24 The effects of CYC on the cellular functions of the T-cells and B-cells may account for its therapeutic efficacy in SLE. CYC has been used with success in the lupus-prone mice. CYC delayed the onset and ameliorated immune-mediated glomerulonephritis in the NZB/NZW mice. 25 In the MRLlpr/lpr mice, CYC reduced lymphoid hyperplasia and inhibited autoimmune phenomena. 26 More recently, it was demonstrated that intra-peritoneal administration of CYC to the MRL-lpr/lpr mice reduced the number of immunoglobulin-producing B-cells and serum levels of IgG and IgG anti-dsdna antibodies, which contributed to a reduction in the incidence of renal disease and mortality in these animals. 27 CYC in Severe Proliferative Lupus Nephritis The NIH group of investigators have conducted a series of randomized trials for severe lupus nephritis The first study showed that intravenous pulse CYC plus oral steroid was shown to be significantly more efficacious than steroid alone in the preservation of renal function beyond 5 years. 10,11 The benefits of CYC was particular apparent in high-risk patients who had more chronic changes on renal biopsy. In the second study, in addition to the demonstration of better efficacy of CYC than pulse MP alone, an extended course of pulse CYC (30 months) was associated with a significantly lower rate of renal relapses than a short course of pulse CYC (6 months). 12 The third study demonstrated superiority of a combination of pulse MP and pulse CYC over pulse MP alone in the induction of remission. 13 Long term observation suggested that pulse MP and CYC might be synergistic. 14 CYC in Membranous Lupus Nephropathy Lupus membranous nephropathy remains a therapeutic enigma. More aggressive treatment is needed for patients with declining renal function or persistent/severe nephrotic syndrome. Uncontrolled studies have shown that azathioprine (AZA), chlorambucil or cyclosporin A, used in conjunction with steroid, is effective. 28 An open study demonstrated that oral steroid and the sequential use of oral CYC and AZA alleviated proteinuria and preserve renal function in 90% of patients with membranous lupus nephropathy who presented with nephrotic syndrome. 29 An ongoing randomized controlled trial for the treatment of membranous lupus nephritis is being conducted by the NIH group. 30 Interim results showed that either pulse CYC or cyclosporin A was more effective than prednisone alone in terms of remission and reduction of proteinuria at 12 months. Routes of CYC and Duration of Therapy Daily oral CYC and prednisone was originally used for treating severe lupus nephritis in the 1970's, and had been shown to be more effective than prednisone alone The demonstration of fewer side effects of intravenous pulse CYC over daily oral CYC in the NIH study 10 has rendered oral CYC out of favor. However, in the NIH study, 10 the median duration of oral CYC treatment was 48 months (daily dose: 1-4 mg/kg/ day). An average patient would have received a cumulative dose of more than 70 grams of CYC. As many of the side effects of CYC like malignancy and ovarian failure are dose-related, 16,36-38 it appears that the greater toxicities of the oral CYC regimens in the NIH study are contributed by the higher cumulative doses rather than the route per se. Regimens consisting of a shorter course (6 months) and a lower daily dose (1-2 mg/kg/day) of oral CYC are associated with a much lower incidence of toxicities. 14,39-41 Whether daily oral CYC is more efficacious than intermittent pulse CYC in lupus nephritis is uncertain. In the NIH study, 10 the superiority of intravenous pulse CYC over oral CYC was not statistically significant. Moreover, the result could not be extrapolated to DPGN as all histological classes of lupus nephritis were included. A recent study compared the outcome of two historical cohorts with lupus related DPGN treated with prednisone 2 Hong Kong Bulletin on Rheumatic Diseases

3 MOK and either 12 intravenous pulses of CYC or 6 months' oral CYC (1-2 mg/kg/day) followed by AZA (2 mg/kg/day). 15 It was demonstrated that the oral CYC regimen had a trend of higher remission rate, fewer renal relapses and lower risk of renal function deterioration when compared to the intravenous arm. This trend was evident at 6 months after treatment and persisted up to 24 months. This suggests that an initial induction with a higher cumulative dose of CYC is more effective. The optimal duration of CYC treatment is again unclear. An extended course of intravenous pulse CYC was associated with a significantly lower cumulative risk of renal relapses than a shorter course of CYC at 5 years follow-up (55% versus 10%, p=0.006). 12 However, this was associated with more side effects such as cervical dysplasia. The Euro-Lupus Nephritis Trial was a multicenter randomized study comparing a higher dose intravenous CYC (8 standard pulses in 12 months) with a lower dose CYC regimen (6 fortnightly pulses of 500 mg) for proliferative lupus nephritis. 18 AZA (2 mg/kg/day) was used as maintenance in both arms. It was shown that treatment failure and renal flares were not significantly more frequent in the lower-dose regimen. However, infective complications were lower, although statistical significance could not be reached. As patients with different histological classes of lupus nephritis were recruited and most patients had relatively mild renal disease, the results from this study could not be extended to high-risk patients. Moreover, the duration of CYC treatment in both arms was shorter than that employed in the NIH studies. It remains to be seen whether the long term efficacy of these less intensive CYC regimens is equivalent to conventional doses and duration of CYC. Renal Flares and Maintenance Therapy Although intravenous pulse CYC is the standard regimen for severe lupus nephritis, less favorable outcome was reported in some uncontrolled studies, with 30-50% of patients developing renal function deterioration within 5 years Non-remission of nephritis is a strong determinant for end stage renal disease. 3,47 Thus, more effective regimens are needed, especially for high-risk patients such as those with high chronicity scores on renal biopsy. 5,6,10,41 Flare of nephritis after discontinuation of CYC is fairly common. Recurrence of nephritis is associated with new immunological and inflammatory insults to the kidney, and cumulative damage will lead to renal function decline. The relapse rate of nephritis after CYC treatment of DPGN ranges from 10% to 66% in various studies, depending on the severity of nephritis on recruitment, treatment regimens, definition of relapse, and the duration of observation. 12,48-50 A recent study by Illei et al 19 reported that 45% of patients who remitted completely or partially after intravenous MP, intravenous CYC, or a combination of both experienced renal relapses after a mean follow-up of 117 months. As renal flares are fairly common after CYC is discontinued, maintenance therapy with a less toxic drug is needed. In a recent multicenter study of 174 SLE patients with DPGN, it was demonstrated that long term AZA (1-2 mg/kg/day) after successful CYC induction was associated with significantly fewer renal flares. 51 Boletis et al 52 compared the efficacy of monthly intravenous immunoglobulin with maintenance intermittent pulse CYC in 14 patients who had completed a 6-month course of pulse CYC for proliferative lupus nephritis. The relapse rate was similar in both arms at 18 months. However, the study was not powered to tell a difference between immunoglobulin and CYC. An ongoing randomized controlled trial in 54 patients with proliferative lupus nephritis demonstrated that maintenance therapy with mycophenolate mofetil (MMF) ( mg/ day) was more effective than either quarterly intravenous pulse CYC ( g/m 2 ) or AZA ( mg/kg/day) in the prevention of renal flares after initial successful induction therapy with pulse CYC. 53 At 42 months, the cumulative probability of renal relapse was highest for CYC (43%). MMF was associated with significantly lower incidence of toxicities than CYC. CYC in Combination with Other Modalities Combination strategies to achieve a synergistic effect and reduce adverse events are being studied. The most recent NIH study showed that pulse MP was synergistic with pulse CYC without enhancing toxicities. 14 A meta-analysis reported that CYC and AZA combination was more effective than prednisone alone in reducing end stage renal failure. 54 The addition of AZA appeared to be CYC-sparing, with a lower daily dose of CYC required and hence less treatment-related toxicities. 10 3

4 CYC IN SEVERE LUPUS NEPHRITIS Nucleoside Analogues Fludarabine is a purine nucleoside analogue with selective activity against both dividing and resting lymphocytes. Lowdose fludarabine depletes both B cells and certain T cell subsets. It was effective and well tolerated in the treatment of refractory idiopathic and lupus membranous nephropathy. 55 Phase I/II study combining fludarabine and monthly lowdose oral pulse CYC in lupus nephritis is underway. Another nucleoside analogue, 2-chloro-2'-deoxyadenosine (2-CdA), has also been evaluated in patients with proliferative lupus glomerulonephritis. Phase I study has established safety and efficacy of this agent in 12 patients. 56 Plasmapheresis Plasmapheresis was proposed to improve the efficacy of CYC treatment of lupus nephritis. However, a randomized trial did not demonstrate benefits of addition of plasmapheresis to a regimen of corticosteroid and oral CYC in severe lupus nephritis. 57 A synchronized plasmapheresis regimen with high-dose CYC was employed by some investigators The idea was to remove the autoantibodies and stimulate a rebound of pathogenic B-cell clones, which were then depleted by the cytotoxic effect of CYC. Despite early reports of success, 58 recent randomized controlled trials did not show superiority of apheresis-cyc over pulse CYC alone in lupus nephritis, although addition of apheresis was associated with a more rapid remission. 59,60 Anti-CD20 Monoclonal Antibody Rituximab is a chimeric mouse/human anti-cd20 monoclonal antibody that depletes B-cells in vivo. 61 Rituximab has been used anecdotally in the treatment of life-threatening SLE. 62 An open study of 6 patients with active SLE who were resistant to various immunosuppressive agents showed improvement in disease activity in 5 patients who received a protocol consisting of high dose oral prednisolone, 2 infusions of rituximab and 2 infusions of intravenous CYC. 63 Depletion of CD+19 B cells lasted for 3-6 months but the change in anti-dsdna titers was variable. Treatment was well tolerated. Immunoablative CYC Therapy Immunoablative high-dose CYC, with stem cell rescue, ablates the pathogenic and autoreactive immune cells in the bone marrow and has been shown to induce remission of SLE for a median of 25 months in 7 patients. 64 Another study using a lower dose of CYC (50 mg/kg/day for 4 consecutive days), followed by granulocyte colony-stimulating factor (G- CSF) stimulation for white cell count recovery but without stem cell rescue, has also demonstrated efficacy in 7 patients with refractory and severe autoimmune diseases, including two patients with SLE. 65 Using the same treatment protocol, the outcome of 14 SLE patients was recently reported. 66 Nine of the patients had corticosteroid-resistant lupus nephritis and 7 patients achieved either a complete or partial response after a mean follow-up of 27 months. Alternative Modalities Alternative treatment modalities may be considered for patients who are reluctant for CYC or intolerant/refractory to the drug. These include AZA, cyclosporin A (CSA), mycophenolate mofetil (MMF), immunoadsorption, intravenous immunoglobulin (IVIG), anti-cd40l monoclonal antibody and LJP394. Other potential therapies for lupus nephritis are the anti-c5 complement monoclonal antibody, anti-interleukin-10 monoclonal antibody, anti-b lymphocyte stimulator (anti-blys) and human recombinant DNAase. 2,67 Because of the word limit, these will not be covered in this article. Conclusions CYC remains the first-line treatment of choice for patients with severe lupus nephritis. Attempts have been made to reduce CYC-related toxicities by modification of existing treatment regimens. A longer observation will tell whether less intensive CYC regimens are equivalent to conventional regimens in terms of efficacy. Combination strategies consisting of CYC and other modalities, and immunoablative high dose CYC are being increasing used in patients with resistant lupus nephritis. Comparative studies of CYC and other immunosuppressive agents are needed so that more therapeutic options can be offered for patients with severe lupus nephritis. References 1. Cameron JS. Lupus nephritis. J Am Soc Nephrol 1999;10: Zimmerman R, Radhakrishnan J, Valeri A, Appel G. Advances in the treatment of lupus nephritis. Annu Rev Med 2001;52: Hong Kong Bulletin on Rheumatic Diseases

5 MOK 3. Mok CC, Wong RWS, Lau CS. Lupus nephritis in Southern Chinese patients: clinicopathological findings and long term outcome. Am J Kidney Dis 1999;34: Yang LY, Chen WP, Lin CY. Lupus nephritis in children a review of 167 patients. Pediatrics 1994;94: Bakir AA, Levy PS, Dunea G. The prognosis of lupus nephritis in African-Americans : a retrospective analysis. Am J Kidney Dis 1994;24: Dooley MA, Hogan S, Jennette C, Falk R. Cyclophosphamide therapy for lupus nephritis: poor renal survival in black Americans. Glomerular Disease Collaborative Network. Kidney Int 1997;51: Lewis EJ, Schwartz MM, Korbet SM. Severe lupus nephritis: importance of re-evaluating the histologic classification and the approach to patient care. J Nephrol 2001;14: Najafi CC, Korbet SM, Lewis EJ, Schwartz MM, Reichlin M, Evans J. Significance of histologic patterns of glomerular injury upon long-term prognosis in severe lupus glomerulonephritis. Kidney Int 2001;59: Sloan RP, Schwartz MM, Korbet SM, Borok RZ. Long-term outcome in systemic lupus erythematosus membranous glomerulonephritis. Lupus Nephritis Collaborative Study Group. J Am Soc Nephrol 1996;7: Austin HA 3rd, Klippel JH, Balow JE, et al. Therapy of lupus nephritis. Controlled trial of prednisone and cytotoxic drugs. New Engl J Med 1986;314: Steinberg AD, Steinberg SC. Long-term preservation of renal function in patients with lupus nephritis receiving treatment that includes cyclophosphamide versus those treated with prednisone only. Arthritis Rheum 1991;34: Boumpas DT, Austin HA 3rd, Vaughn EM, et al. Controlled trial of pulse methylprednisolone versus two regimens of pulse cyclophosphamide in severe lupus nephritis. Lancet 1992;340: Gourley MF, Austin HA 3rd, Scott D, et al. Methylprednisolone and cyclophosphamide, alone or in combination, in patients with lupus nephritis. A randomized, controlled trial. Ann Intern Med 1996;125: Illei GG, Austin HA, Crane M, et al. Combination therapy with pulse cyclophosphamide plus pulse methylprednisolone improves long-term renal outcome without adding toxicity in patients with lupus nephritis. Ann Intern Med 2001;135: Mok CC, Ho CTK, Siu YP, et al. Treatment of diffuse proliferative lupus glomerulonephritis: a comparison of two cyclophosphamide-containing regimens. Am J Kidney Dis 2001;38: Mok CC, Lau CS, Wong RWS. Risk factors for ovarian failure in patients with systemic lupus erythematosus receiving cyclophosphamide therapy. Arthritis Rheum 1998;41: Houssiau FA, Jadoul M. Cytotoxic therapy of lupus nephritis: recent developments. Nephrol Dial Transplant 2002;17: Houssiau FA, Vasconcelos C, D'Cruz D, et al. Immunosuppressive therapy in lupus nephritis: the Euro-Lupus Nephritis Trial, a randomized trial of low-dose versus highdose intravenous cyclophosphamide. Arthritis Rheum 2002; 46: Illei GG, Takada K, Parkin D, et al. Renal flares are common in patients with severe proliferative lupus nephritis treated with pulse immunosuppressive therapy: long-term followup of a cohort of 145 patients participating in randomized controlled studies. Arthritis Rheum 2002;46: Takada K, Illei GG, Boumpas DT. Cyclophosphamide for the treatment of systemic lupus erythematosus. Lupus 2001;10: Fox DA, McCune WJ. Immunosuppressive drug therapy of systemic lupus erythematosus. Rheum Dis Clin North Am 1994;20: McCune WJ, Golbus J, Zeldes W, Bohlke P, Dunne R, Fox DA. Clinical and immunologic effects of monthly administration of intravenous cyclophosphamide in severe systemic lupus erythematosus. N Engl J Med 1988;318: Cupps TR, Edgar LC, Fauci AS. Suppression of human B lymphocyte function by cyclophosphamide. J Immunol 1982; 128: Varkila K, Hurme M. The effect of cyclophosphamide on cytotoxic T-lymphocyte responses: inhibition of helper T-cell induction in vitro. Immunology 1983;48: Cavallo T, Graves K, Granholm NA. Murine lupus nephritis: effects of cyclophosphamide on circulating and tissue bound immunoreactants. Clin Exp Immunol 1984;55: Woo J, Wright TM, Lemster B, Borochovitz D, Nalesnik MA, Thomson AW. Combined effects of FK506 (tacrolimus) and cyclophosphamide on atypical B220+ T cells, cytokine gene expression and disease activity in MRL/MpJ-lpr/lpr mice. Clin Exp Immunol 1995;100: Jonsson CA, Svensson L, Carlsten H. Beneficial effect of the inosine monophosphate dehydrogenase inhibitor mycophenolate mofetil on survival and severity of glomerulonephritis in systemic lupus erythematosus (SLE)- prone MRLlpr/lpr mice. Clin Exp Immunol 1999;116: Kolasinski SL, Chung JB, Albert DA. What do we know about lupus membranous nephropathy? An analytic review. Arthritis Rheum 2002;47: Chan TM, Li FK, Hao WK, et al. Treatment of membranous lupus nephritis with nephrotic syndrome by sequential immunosuppression. Lupus 1999;8: Austin HA, Vaughan EM, Balow JE. Lupus membranous nephropathy: randomized controlled trial of prednisone, cyclosporine and cyclophosphamide. [abstract] J Am Soc Nephrol 2000;11:81A. 31. Ginzler E, Diamond H, Guttadauria M, Kaplan D. Prednisone and azathioprine compared to prednisone plus low-dose azathioprine and cyclophosphamide in the treatment of diffuse lupus nephritis. Arthritis Rheum 1976;19: Donadio JV Jr, Holley KE, Ferguson RH, Ilstrup DM. Progressive lupus glomerulonephritis. Treatment with 5

6 CYC IN SEVERE LUPUS NEPHRITIS prednisone and combined prednisone and cyclophosphamide. Mayo Clin Proc 1976;51: Donadio JV Jr, Holley KE, Ferguson RH, Ilstrup DM. Treatment of diffuse proliferative lupus nephritis with prednisone and combined prednisone and cyclophosphamide. N Eng J Med 1978;299: Steinberg AD, Decker JL. A double-blind controlled trial comparing cyclophosphamide, azathioprine and placebo in the treatment of lupus glomerulonephritis. Arthritis Rheum 1974;17: Dinant HJ, Decker JL, Klippel JH, Balow JE, Plotz PH, Steinberg AD. Alternative modes of cyclophosphamide and azathioprine therapy in lupus nephritis. Ann Intern Med 1982; 96(6 Pt 1): Radis CD, Kahl LE, Baker GL, et al. Effects of cyclophosphamide on the development of malignancy and on longterm survival of patients with rheumatoid arthritis. A 20-year follow-up study. Arthritis Rheum 1995;38: Wang CL, Wang F, Bosco JJ. Ovarian failure in oral cyclophosphamide treatment for systemic lupus erythematosus. Lupus 1995;4: Boumpas DT, Austin HA 3rd, Vaughan EM, Yarboro CH, Klippel JH, Balow JE. Risk for sustained amenorrhea in patients with systemic lupus erythematosus receiving intermittent pulse cyclophosphamide therapy. Ann Intern Med 1993;119: Chan TM, Li FK, Wong RW, Wong KL, Chan KW, Cheng IK. Sequential therapy for diffuse proliferative and membranous lupus nephritis: cyclophosphamide and prednisone followed by azathioprine and prednisone. Nephron 1995;71: Chan TM, Li FK, Tang CS, et al. Efficacy of mycophenolate mofetil in patients with diffuse proliferative lupus nephritis. Hong Kong-Guangzhou Nephrology Study Group. N Engl J Med 2000;343: Mok CC, Ho CTK, Chan KW, Lau CS, Wong RWS. Outcome and prognostic indicators of diffuse proliferative lupus glomerulonephritis treated with sequential oral cyclophosphamide and azathioprine. Arthritis Rheum 2002; 46: Sesso R, Monteiro M, Sato E, Kirsztajn G, Silva L, Ajzen H. A controlled trial of pulse cyclophosphamide versus pulse methylprednisolone in severe lupus nephritis. Lupus 1994;3: Valeri A, Radhakrishnan J, Estes D, et al. Intravenous pulse cyclophosphamide treatment of severe lupus nephritis: a prospective five-year study. Clin Nephrol 1994;42: Belmont HM, Storch M, Buyon J, Abramson S. New York University/Hospital for Joint Diseases experience with intravenous cyclophosphamide treatment: efficacy in steroid unresponsive lupus nephritis. Lupus 1995;4: Martinelli R, Pereira LJ, Santos ES, Rocha H. Clinical effects of intermittent, intravenous cyclophosphamide in severe systemic lupus erythematosus. Nephron 1996;74: Conlon PJ, Fischer CA, Levesque MC, et al. Clinical, biochemical and pathological predictors of poor response to intravenous cyclophosphamide in patients with proliferative lupus nephritis. Clin Nephrol 1996;46: Korbet SM, Lewis EJ, Schwartz MM, Reichlin M, Evans J, Rohde RD. Factors predictive of outcome in severe lupus nephritis. Lupus Nephritis Collaborative Study Group. Am J Kidney Dis 2000;35: Ciruelo E, de la Cruz J, Lopez I, Gomez-Reino JJ. Cumulative rate of relapse of lupus nephritis after successful treatment with cyclophosphamide. Arthritis Rheum 1996;39: Moroni G, Quaglini S, Maccario M, Banfi G, Ponticelli C. "Nephritic flares" are predictors of bad long-term renal outcome in lupus nephritis. Kidney Int 1996;50: Ioannidis JP, Boki KA, Katsorida ME, et al. Remission, relapse, and re-remission of proliferative lupus nephritis treated with cyclophosphamide. Kidney Int 2000;57: Mok CC, Ying KY, Tang CW, Ng WL, Wong RWS, Lau CS. Role of azathioprine in the prevention of renal relapses after successful cyclophosphamide induction of diffuse proliferative lupus glomerulonephritis. [abstr] Arthritis Rheum 2002;46(9 Suppl):S Boletis JN, Ioannidis JP, Boki KA, Moutsopoulos HM. Intravenous immunoglobulin compared with cyclophosphamide for proliferative lupus nephritis. Lancet 1999;354: Contreras G, Pardo V, Leclercq B, et al. Maintenance therapy for proliferative forms of lupus nephritis: a randomized clinical trial comparing quarterly intravenous cyclophosphamide versus oral mycophenolate mofetil or azathioprine. [abstr] J Am Soc Nephrol 2002;13:15A. 54. Bansal VK, Beto JA. Treatment of lupus nephritis: a metaanalysis of clinical trials. Am J Kidney Dis 1997;29: Boumpas DT, Tassiulas IO, Fleisher TA, et al. A pilot study of low-dose fludarabine in membranous nephropathy refractory to therapy. Clin Nephrol 1999;52: Davis JC Jr, Austin H 3rd, Boumpas D, et al. A pilot study of 2-chloro-2'-deoxyadenosine in the treatment of systemic lupus erythematosus-associated glomerulonephritis. Arthritis Rheum 1998;41: Lewis EJ, Hunsicker LG, Lan SP, Rohde RD, Lachin JM. A controlled trial of plasmapheresis therapy in severe lupus nephritis. The Lupus Nephritis Collaborative Study Group. N Engl J Med 1992;326: Euler HH, Schroeder JO, Harten P, Zeuner RA, Gutschmidt HJ. Treatment-free remission in severe systemic lupus erythematosus following synchronization of plasmapheresis with subsequent pulse cyclophosphamide. Arthritis Rheum 1994;37: Wallace DJ, Goldfinger D, Pepkowitz SH, et al. Randomized controlled trial of pulse/synchronization cyclophosphamide/ apheresis for proliferative lupus nephritis. J Clin Apheresis 1998;13: Danieli MG, Palmieri C, Salvi A, Refe MC, Strusi AS, Danieli G. Synchronised therapy and high-dose cyclophosphamide in proliferative lupus nephritis. J Clin Apheresis 2002;17: Hong Kong Bulletin on Rheumatic Diseases

7 MOK 61. Maloney DG. Preclinical and phase I and II trials of rituximab. Semin Oncol 1999;26(5 Suppl 14): Perrotta S, Locatelli F, La Manna A, Cennamo L, De Stefano P, Nobili B. Anti-CD20 monoclonal antibody (Rituximab) for life-threatening autoimmune haemolytic anaemia in a patient with systemic lupus erythematosus. Br J Haematol 2002;116: Leandro MJ, Edwards JC, Cambridge G, Ehrenstein MR, Isenberg DA. An open study of B lymphocyte depletion in systemic lupus erythematosus. Arthritis Rheum 2002;46: Traynor AE, Schroeder J, Rosa RM, et al. Treatment of severe systemic lupus erythematosus with high-dose chemotherapy and haemopoietic stem-cell transplantation: a phase I study. Lancet 2000;356: Brodsky RA, Petri M, Smith BD, et al. Immunoablative highdose cyclophosphamide without stem-cell rescue for refractory, severe autoimmune disease. Ann Intern Med 1998; 129: Petri M, Jones RJ, Brodsky RA. High-dose cyclophosphamide without stem cell transplantation in systemic lupus erythematosus. Arthritis Rheum 2003;48: Wallace DJ. Management of lupus erythematosus: recent insights. Curr Opin Rheumatol 2002;14: