Long-term Outcome of Diffuse Proliferative Lupus Glomerulonephritis Treated with Cyclophosphamide

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1 The American Journal of Medicine (2006) 119, 355.e e33 CLINICAL RESEARCH STUDY Long-term Outcome of Diffuse Proliferative Lupus Glomerulonephritis Treated with Cyclophosphamide Chi Chiu Mok, MD, FRCP, a King Yee Ying, MB, MRCP, b Woon Leung Ng, MB, MRCP, c Ka Wing Lee, MB, MRCP, d Chi Hung To, MB, MRCP, a Chak Sing Lau, MD, FRCP, e Raymond Woon Sing Wong, MB, FRCP, e Tak Cheung Au, MB, FRCP a a Department of Medicine, Tuen Mun Hospital; b Princess Margaret Hospital; c Department of Medicine, United Christian Hospital; d Pamela Youde Eastern Hospital; and e Queen Mary Hospital, Hong Kong, China. ABSTRACT PURPOSE: To report the long-term outcome of diffuse proliferative lupus nephritis (DPLN) treated with cyclophosphamide (CYC) in Chinese patients. METHODS: Patients with biopsy-proven DPLN treated with prednisolone and CYC were identified. The long-term renal outcome and treatment-related toxicities were reported. RESULTS: A total of 212 patients were studied (89% women; mean age years; mean system lupus erythematosus [SLE] duration months). At renal biopsy, 148 (70%) patients were nephrotic, and 78 (37%) had impaired serum creatinine. One hundred and three (49%) patients received daily oral CYC, whereas 109 (51%) received intravenous bolus CYC. At last dose of CYC, 126 (59%) patients responded completely, and 56 (26%) responded partially. In a logistic regression model, the cumulative CYC dose and histologic chronicity score predicted complete response. One hundred fifty-five (73%) patients received maintenance immunosuppression for at least 3 years (88% azathioprine). After a follow-up of 1873 patient-years, 66 patients experienced renal flares, 30 had doubling of serum creatinine, 18 developed end-stage renal failure, and 14 died. The renal survival rates were 88.7%, 82.8% and 70.7% at 5, 10 and 15 years, respectively. Failure to respond completely to CYC and the absence of maintenance immunosuppression were independent predictors of a poor renal outcome. Ovarian toxicity was more frequent with the oral CYC regimen. Increasing age and higher cumulative doses of CYC were independent risk factors. CONCLUSIONS: In Chinese patients with DPLN, the cumulative dose, rather than the route of CYC administration, determines the initial treatment response and ovarian toxicity. Maintenance immunosuppression is associated with a better long-term prognosis. The oral CYC regimen is more toxic and should be reserved for high-risk patients Elsevier Inc. All rights reserved. KEYWORDS: Cytotoxic; Immunosuppressive; Prognosis; Glomerulonephritis; Renal; Toxicity Despite the emergence of newer immunosuppressive and immunomodulatory therapies, cyclophosphamide (CYC) remains the first line treatment for severe lupus nephritis. 1 Prolonged observation has confirmed the benefit of CYC in the preservation of renal function, 2-6 whereas equally longterm data are still unavailable for the newer modalities. A Requests for reprints should be addressed to Dr. Chi Chiu Mok, MD, FRCP, Consultant rheumatologist, Department of Medicine and Geriatrics, Tuen Mun Hospital, New Territories, Hong Kong. address: ccmok2005@yahoo.com. recent updated meta-analysis on 25 randomized controlled trials in lupus nephritis indicates that regimens consisting of CYC offer better renal protection than other immunosuppressive protocols. 7 Renal disease is fairly common in southern Chinese patients with system lupus erythematosus (SLE). A prospective study involving 216 new-onset Chinese SLE patients under the care of all specialists in 2 nonacademic hospitals in Hong Kong describes a 60% 5-year cumulative prevalence of renal disease, 8 according to the 1982 American College of Rheumatology (ACR) criteria. 9 An earlier /$ -see front matter 2006 Elsevier Inc. All rights reserved. doi: /j.amjmed

2 355.e26 The American Journal of Medicine, Vol 119, No 4, April 2006 study of 183 patients with biopsy-proven lupus nephritis, who were followed in an academic rheumatology unit, reported the 5-, 10- and 15-year renal survival rates to be 92%, 81% and 75%, respectively. 10 However, patients in all World Health Organization (WHO) histological classes were analyzed, and patients had received heterogeneous treatment regimens that included prednisolone alone or prednisolone combined with azathioprine (AZA) or CYC. The long-term outcome of Chinese patients with diffuse proliferative lupus glomerulonephritis (DPLN) treated with the sequential oral CYC and AZA regimen in our locality was reported recently. 11,12 However, the relatively small sample size in these single-centered studies might suffer from sampling bias and might not necessarily be representative of the overall experience in Hong Kong. In fact, both intravenous pulse CYC and oral CYC are being used for the treatment of DPLN by physicians working in different hospitals. 13 In order to have a clearer picture of the long-term outcome of patients with histologically proven DPLN treated with CYC in Hong Kong, we have gathered a large cohort of patients from 5 regional service hospitals. In a recent publication we reported that among 155 patients with DPLN who initially responded completely or partially to combined prednisolone and CYC the renal survival rates at 5 years and 10 years were 95% and 88%, respectively. 14 However, these figures did not take into consideration of those patients who were initially refractory to CYC therapy. In the current study, we further expanded the cohort size by nesting patients for 1 more year between 1988 and 2002, and updated their clinical status after a longer period of observation. The long-term outcomes of our patients, in terms of renal function decrease, end-stage renal failure (ESRF) and survival, and their clinical determinants, were analyzed. Adverse effects of CYC with regard to the different routes of CYC administration were compared. CLINICAL SIGNIFICANCE METHODS Study Population Between 1988 and 2002, all patients with renal biopsyproven diffuse proliferative lupus glomerulonephritis (Class IV nephritis according to the revised 1995 WHO classification 15 ) treated in 5 regional hospitals of Hong Kong were identified from either the hospital clinical registries or the pathologists renal biopsy databases. All patients had to fulfill at least 4 of the American College of Rheumatology The 10-year renal survival of 212 Chinese patients with diffuse proliferative lupus nephritis treated with oral or intravenous bolus cyclophosphamide was 83%. The cumulative doses of cyclophosphamide, but not the route of administration, determined the clinical response. Treatment resistance and absence of maintenance immunosuppression were predictors of poor long-term outcome. Daily oral cyclophosphamide was more toxic to the ovaries and should be reserved for high-risk patients. (ACR) criteria for the classification of SLE. 9 Those patients who were treated initially with corticosteroids and CYC were further analyzed. Demographic data, body weight, and various clinical and biochemical parameters were obtained from the patients studied. This included blood pressure, histologic activity and chronicity scores, 24-hour proteinuria, serum creatinine, creatinine clearance, serum albumin, serum C3 levels, and anti-dsdna antibody at the time of renal biopsy. The cumulative doses of CYC and prednisolone per kilogram of body weight received by patients were calculated, and the clinical status of the patients (complete response, partial response, nonresponse) at the last dose of CYC treatment was evaluated. The long-term outcome of the patients in terms of doubling of baseline serum creatinine, development of end-stage renal failure (ESRF) and death also was determined. Clinical predictors of complete response to CYC and the composite outcome from doubling of serum creatinine, ESRF and death were studied by statistical analyses. Adverse effects related to the use of CYC also were obtained and compared between the 2 routes of CYC administration. Renal biopsy specimens were examined by light, immunofluorescence, and electron microscopy. Activity (maximum score 24 points) and chronicity (maximum 12 points) indices were determined according to the histologic criteria described previously. 16 Pathologists were blinded for the clinical status and treatment regimens of the patients studied. Treatment Protocols All our patients were treated with either intravenous pulse or daily oral CYC. The assignment of treatment regimens were based on the preferences of both the physicians and the patients. For intravenous CYC, the initial dose was 0.5 g/m 2 of body surface area, targeting 1 g/m 2 according to the white blood cell nadir. Six consecutive monthly pulses were given, followed by another 6 pulses given every 3 months. Intravenous metoclopramide was routinely given before each CYC infusion, but the use of other antiemetics, such as ondansetron, was up to the decision of individual physicians. For oral CYC the daily dose was 1-2 mg/kg, given continuously for 6 to 9 months. In both cases, the exact dose of CYC, number of pulses, and duration of treatment were adjusted according to patients tolerability, presence of severe infection, and other adverse events. In addition, corticosteroids (prednisone mg/kg/day or equivalent) were given initially for 6-8 weeks, after which they were

3 Mok et al Long-term Outcome of Lupus Nephritis Treated with CYC 355.e27 tapered to a maintenance dose (prednisone 5-10 mg/day) and continued indefinitely. When a clinical response was achieved, the use of maintenance immunosuppression, such as azathioprine (AZA), was made at the discretion of the attending physicians. Alternative induction regimens, such as intravenous pulse methylprednisolone, cyclosporin A (CSA), and mycophenolic mofetil (MMF), could be used as rescue therapy for patients who were initially refractory to CYC. Definitions of Treatment Response and Renal Flares Complete response (CR), partial response (PR), and nonresponse (NR) were defined as suggested by Boumpas and Balow, 17 with modifications. CR was defined as stabilization or improvement in serum creatinine level with reduction of proteinuria to 1 gm/day, improvement in C3 level, and complete resolution of active urinary casts for at least 6 months. PR was defined as stabilization or improvement in serum creatinine level with persistent reduction of proteinuria (if nephrotic range at baseline, a 50% decrease in proteinuria and 3 gm/day; if non-nephrotic at baseline, a decrease to 50% of the pretreatment value but 1 gm/ day), improvement in C3 level, and reduction in active urinary casts ( 5/high-power field [HPF]) for at least 6 months. NR referred to a deterioration of renal function exclusive of other causes (such as sepsis, nephrotoxic agents, overdiuresis, and renal vein thrombosis), an increase in proteinuria, or a reduction in proteinuria but not to the extent of CR or PR, or persistence of active urinary casts ( 5/HPF). Patients who fulfilled the criteria for CR or PR initially but the response did not persist for 6 months or more were analyzed as NR. A proteinuric renal flare was defined as an increase in proteinuria to more than 2 g/day after a CR, or a doubling of proteinuria in patients who achieved PR, with or without an increase in serum creatinine level. A nephritic flare was defined as an increase or recurrence of active urinary sediments ( 10/high power field), with or without a concomitant increase in proteinuria or serum creatinine level. Definitions of Transient and Permanent Amenorrhea Transient amenorrhea referred to amenorrhea for more than 2 months during CYC treatment. Premature ovarian failure was defined as having sustained amenorrhea for more than 12 months after cessation of CYC in patients under the age of 40 years, with documentation by postmenopausal ranges of blood follicle-stimulating hormone (FSH) and estradiol levels. Statistical Analyses Unless otherwise specified, values in this study were expressed as mean SD (standard deviation). Comparison of categorical data between 2 groups was made by the chisquared test. Yates continuity correction was performed when the frequency was small. Continuous data between 2 groups was compared by the Student s t test. When normal distribution or equal variance could not be assumed, the Mann-Whitney rank sum test was used instead. Logistic regression was used to study the factors associated with complete response (CR) at the last dose of CYC. Covariates tested were: age at the time of renal biopsy, sex, SLE duration, histologic activity and chronicity scores, route of CYC administration, cumulative dose of CYC per kilogram of body weight, cumulative dose of prednisone per kilogram of body weight in the first 4 months, serum creatinine level, proteinuria, presence of nephrotic syndrome, creatinine clearance, serum albumin level, low C3 level, positive anti-dsdna antibody, and hypertension at the time of renal biopsy. Timing and the cumulative risks of the composite outcome of doubling of serum creatinine, ESRF and death were studied by Kaplan-Meier analysis. Time zero referred to the time of renal biopsy. Doubling of serum creatinine had to be sustained for at least 4 months, and the time of ESRF referred to the time when renal replacement therapy was initiated. Multivariate analysis for clinical predictors of this composite outcome was performed by the Cox proportional hazard model. Covariates tested were: age at the time of renal biopsy, sex, SLE duration, histologic activity and chronicity scores, route of CYC administration, cumulative dose of CYC per kilogram of body weight, cumulative prednisone dose per kilogram of body weight in the first 4 months, complete response after initial CYC treatment, clinical parameters at the last dose of CYC (serum creatinine level, proteinuria, creatinine clearance, serum albumin, low C3 level, positive anti-dsdna antibody and hypertension requiring therapy), use of maintenance immunosuppression (AZA, CSA or MMF) for 3 years, occurrence of nephritic renal flares, and the development of sustained amenorrhea for 12 months during follow-up. Logistic regression was again employed to study the clinical factors associated with the development of CYC-induced sustained amenorrhea. Covariates tested were: age, SLE duration, route of CYC administration, cumulative dose of CYC per unit of body weight, cumulative prednisone dose per unit of body weight in the first 4 months, and the use of maintenance immunosuppression for 3 years or more. Statistical significance was defined as a P value of.05, 2-tailed. All statistical analyses were performed using the SPSS program, version 11.5 (SPSS, Chicago, Ill) for Windows XP. RESULTS Demographic Data and Baseline Renal Parameters A total of 268 patients with diffuse proliferative lupus nephritis confirmed by renal biopsy were identified. Two hundred twelve patients (188 women, 24 men) were initially treated with prednisolone and CYC. All were ethnic Chinese. The mean age was years, and the mean

4 355.e28 The American Journal of Medicine, Vol 119, No 4, April 2006 Table 1 Clinical Characteristics and Renal Parameters of Our Patients with Diffuse Proliferative Lupus Nephritis Treated with CYC Oral CYC (n 103) IV CYC (n 109) Mean SD; Number (%) All (n 212) Age at time of renal biopsy, years Female 89 (86) 99 (91) 188 (89) SLE duration at time of nephritis, months Length of follow-up since renal biopsy, months** Parameters at renal biopsy Histologic activity score, range 0-24* Histologic chronicity score, range Body weight, kg Serum creatinine, mol/l Serum creatinine 106 mol/l 40 (39) 38 (35) 78 (37) Creatinine clearance, ml/min Proteinuria in 24 h, gm Nephrotic syndrome* 63 (61) 85 (78) 148 (70) Serum albumin, gm/l Depressed serum C3 level 93 (90) 98 (90) 191 (90) Hypertension (BP 140/90 mm Hg) 36 (35) 37 (34) 73 (34) Positive anti-dsdna 90 (87) 97 (89) 187 (88) Cyclophosphamide treatment Cumulative dose, gm** Cumulative dose per unit BW, mg/kg** Cumulative prednisolone dose in first 4 months, mg/kg IV intravenous; SD standard deviation; SLE systemic lupus erythematosus; BP blood pressure; BW body weight. To convert serum creatinine in mg/dl to mol/l, multiply by *P.05 (comparison between oral cyclophosphamide and IV cyclophosphamide). **P.01 (comparison between oral cyclophosphamide and IV cyclophosphamide). SLE duration was months. At the time of renal biopsy, 70% of patients were nephrotic, 37% had impaired serum creatinine level ( 106 umol/l), and 34% were hypertensive (blood pressure 140/90 mmhg). The demographic data and various renal parameters are shown in Table 1. One hundred three (49%) patients were treated with oral CYC, and 109 (51%) patients were treated with intravenous pulse CYC. Patients treated with oral CYC had higher histologic activity scores and were less likely to be nephrotic. The oral CYC regimen was associated with a significantly higher cumulative dose of CYC per unit of body weight than the intravenous regimen. However, the cumulative doses of prednisolone between the 2 groups of patients were not significantly different. Treatment Response to CYC At the last dose of CYC, 126 (59%) patients had complete response, and 56 (26%) had partial response. The oral CYC Table 2 Treatment Response at the Last Dose of CYC Oral CYC n 103 IV pulse CYC n 109 All n 212 Complete response 71 (69%) 55 (50%) 126 (59%) Partial response 25 (24%) 31 (28%) 56 (26%) Nonresponse 7 (7%) 23 (21%) 30 (14%) IV intravenous; CYC cyclophosphamide. P.004 by chi-squared (2 3 table). regimen was associated with a significantly higher rate of response (P.004) by chi-squared analysis (Table 2). Table 3 shows the odds ratios of each covariate for complete response to CYC treatment by binary logistic regression. In univariate analysis, a lower chronicity score, less serious renal presentation (in terms of proteinuria, serum creatinine, creatinine clearance, serum albumin level and presence of hypertension), the oral route of CYC administration, and a higher cumulative dose of CYC were associated with complete response. However, the route of CYC administration was no longer significant in the multivariate model. Independent factors associated with complete response to CYC were cumulative CYC dose (relative risk [RR] 2.17 [ ] per 100 mg/kg body weight; P.001) and the histologic chronicity score (RR 0.67 [ ] per point; P.001). Renal Flares, Nonrenal Flares and Long-term Outcome One hundred fifty-five (73%) patients received maintenance immunosuppression for at least 3 years. Azathioprine was the most common choice (88%), followed by mycophenolate mofetil (6%), and cyclosporin A (6%). The use of maintenance immunosuppression was more frequent in those patients treated initially with oral CYC than intravenous CYC (87/103 [84%] in oral CYC group vs 68/109 [62%] in intravenous CYC group; P.001 by chi-squared analysis). After a total follow-up of 1873 patient-years, 66 patients experienced renal flares (incidence 35/1000 patient-year; 38% nephritic flares

5 Mok et al Long-term Outcome of Lupus Nephritis Treated with CYC 355.e29 Table 3 Predictors of Complete Response to CYC Treatment Univariate Multivariate Covariates RR [95% CI] P value RR [95% CI] P value Female 1.45 [ ] [ ].40 Age at renal biopsy, per year 0.997[ ] [ ].19 SLE duration, per month 0.997[ ] [ ].85 Histologic activity score, per point 0.992[ ] [ ].47 Histologic chronicity score, per point 0.81 [ ] [ ].001 Positive anti-dsdna 2.19 [ ] [ ].23 Depressed C3 level 1.76 [ ] [ ].08 Proteinuria, per gm/day 0.91 [ ] [ ].65 Nephrotic syndrome 0.52 [ ] [ ].91 Hypertension (BP 140/90 mm Hg) 0.42 [ ] [ ].14 Serum creatinine, per mol/l 0.99 [ ] [ ].10 Creatinine clearance, per ml/min 1.01 [ ] [ ].48 Serum albumin, per gm/l 1.04 [ ] [ ].56 Oral CYC vs. IV pulse CYC 2.25 [ ] [ ].44 Cumulative doses of CYC (per 100 mg/kg) 1.73 [ ] [ ].001 Cumulative prednisolone dose in 4 months (per 10 mg/kg) 0.96 [ ] [ ].15 RR relative risk; CI confidence interval; CYC cyclophosphamide; SLE systemic lupus erythematosus, BP blood pressure; IV intravenous. To convert serum creatinine in mg/dl to mol/l, multiply by and 62% proteinuric flares); 30 had doubling of serum creatinine (incidence 16/1000 patient-year); 18 developed end-stage renal failure (ESRF) (incidence 9.6/1000 patient-year); and 14 died (incidence 7.5/1000 patient-year). Causes of death were infective complications in 43% patients and cerebrovascular/ cardiovascular in 29% patients. The cumulative renal survival rates (survival without dialysis) were 88.7%, 82.8% and 70.7% at 5, 10 and 15 years, respectively. Thirty-three patients experienced 48 episodes of nonrenal flares (incidence 25.6/1000 patient-year; 42% arthritic flare, 19% dermatological flare, 27% hematological flare, 6% serositis and 6% neuropsychiatric flare). Table 4 Predictors of the Composite Outcome of Doubling of Serum Creatinine, End Stage Renal Failure and Mortality Univariate Multivariate Covariates HR [95% CI] P value HR [95% CI] P value Female 0.67[ ] [ ].84 Age at renal biopsy, per year 1.02[ ] [ ].58 SLE duration, per month 1.01[ ] [ ].79 Histologic activity score, per point 1.07[ ] [ ].20 Histologic chronicity score, per point 1.29[ ] [ ].85 Positive anti-dsdna* 1.64[ ] [ ].85 Depressed C3 level* 2.32[ ] [ ].88 Proteinuria, per gm/day* 1.16[ ] [ ].52 Hypertension requiring therapy* 4.50[ ] [ ].07 Serum creatinine, per mol/l* 1.01[ ] [ ].49 Creatinine clearance, per ml/min* 0.94[ ] [ ].22 Serum albumin, per gm/l* 0.90[ ] [ ].37 Nephrotic syndrome* 4.88[ ] [ ].64 Failure of CR to CYC 6.67[ ] [ ].02 Oral CYC vs IV pulse CYC 0.57[ ] [ ].83 Cumulative doses of CYC (per 100 mg/kg) 0.73[ ] [ ].50 Cumulative prednisolone dose in 4 months (per 10 mg/kg) 1.03[ ] [ ].37 Maintenance immunosuppression 3 years 3.49[ ] [ ].02 Nephritic renal flare 2.13[ ] [ ].17 Sustained amenorrhea 12 months 0.79[ ] [ ].89 HR hazard ratio; CI confidence interval; SLE systemic lupus erythematosus; CR complete response; CYC cyclophosphamide; IV intravenous. To convert serum creatinine in mg/dl to mol/l, multiply by 88.4 (133 mol/l 1.5 mg/dl). *At last dose of CYC.

6 355.e30 The American Journal of Medicine, Vol 119, No 4, April 2006 Table 5 Adverse Effects of CYC with Regard to the Route of Administration Oral CYC (n 103) IV CYC (n 109) P value Number (%) Number (%) Infections requiring hospitalization 18 (17) 23 (21).50 Herpes zoster 20 (19) 17 (16).46 Minor infections (eg, URT, UT) 27 (26) 23 (21).38 Hemorrhagic cystitis 2 (2) 2 (2) 1.00 Transient amenorrhea ( 2 months)* 33/89 (37) 20/99 (20).01 Ovarian failure* 25/89 (28) 13/99 (13).01 Nausea, vomiting 7 (7) 20 (18).01 Leukopenia (WBC /L) 7 (7) 5 (5).69 Mucositis 3 (3) 0 (0).23 Alopecia 32 (31) 25 (23).18 Malignancy Cervical cancer 4 (4) 4 (4) 1.00 Vulval cancer 1 (1) 0 (0).98 Bladder cancer 0 (0) 1 (1) 1.00 CYC cyclophosphamide; IV intravenous; URT upper respiratory tract; UT urinary tract; WBC white cell count. *In female patients only. Predictors of Adverse Renal Outcome Table 4 shows the results of Cox regression analyses for predictors of a composite outcome of creatinine doubling, ESRF, and death. Factors associated with poor outcome on univariate analysis were: higher chronicity scores, longer SLE duration, less favorable renal parameters, persistently low C3 levels at last dose of CYC, failure to respond completely to CYC, lower cumulative doses of CYC received, and the absence of maintenance immunosuppression. In the multivariate model, failure to achieve complete response to CYC (hazard ratio [HR] 4.49 [ ]; P.02) and the absence of maintenance immunosuppression (HR 4.62 [ ]; P.02) remained independently associated with a poor outcome. The Figure shows the event-free survival of the composite outcome of creatinine doubling, ESRF, and death in our patients. Effect of Center on Renal Outcome Of the 5 participating units, only Queen Mary Hospital was an academic hospital. Fifty-five (53%) patients treated with oral CYC were followed in this center. The preference for oral CYC was significantly higher when compared with the other 4 centers (P.001 by chisquare analysis). A separate analysis (data not shown) revealed that the composite outcome of creatinine doubling, ESRF, and death was better in the academic center as compared with nonacademic centers (HR 0.76 [ ]), but the difference was not statistically significant (P.47). Adverse Effects of CYC Table 5 shows the adverse events related to CYC with regard to its route of administration. No significant differences in the incidence of herpes zoster, major or minor infections, cystitis, severe leukopenia, or malignancies could be demonstrated between the 2 groups of patients. Transient and sustained amenorrhea was more common in patients treated with oral CYC, whereas gastrointestinal events were more common in those treated with intravenous CYC. A separate logistic regression analysis revealed that the cumulative dose of CYC (odds ratio 1.48 [ ] per 100 mg/kg; P.01) and increasing age (odds ratio 1.07 [ ] per year; P.001) were independent risk factors of CYC-induced ovarian failure (Table 6). Table 6 Multivariate Predictors of Permanent Amenorrhea after CYC Treatment Clinical predictors RR [95% CI] P value Age, per year 1.07 [ ].001 SLE duration, per month 1.00 [ ].52 Oral vs. IV pulse CYC 1.78 [ ].23 Cumulative dose of CYC/BW, per 100 mg/kg 1.48 [ ].01 Cumulative prednisolone dose in 4 months (per 10 mg/kg) 1.15 [ ].28 Maintenance immunosuppression 3 years 0.47 [ ].12 RR relative risk; CI confidence interval; SLE systemic lupus erythematosus; IV intravenous; CYC cyclophosphamide; BW body weight

7 Mok et al Long-term Outcome of Lupus Nephritis Treated with CYC 355.e31 DISCUSSION This is a retrospective review of the long-term outcome of a very large cohort of patients with DPLN treated initially with prednisolone and CYC and followed prospectively in 5 regional hospitals of Hong Kong. As CYC protocols being used and the monitoring strategies for patients are similar in these centers, longitudinal data are available for analysis. Using the hospital clinical and pathology registries, we believe that we have nested all the patients within the specified period to minimize sampling error. With such a large cohort of patients, the long-term renal survival figures are likely to be a true reflection of the experience of Chinese patients with DPLN generally seen by rheumatologists in our local setting. In the current study, the 10-year and 15-year renal survival rates of DPLN treated with CYC were 83% and 71%, respectively. This is in keeping with the data reported for Caucasian patients with DPLN in Europe and in the US. 3,4,18-20 Direct comparison is confounded by the differences in severity of renal disease at entry, treatment regimens employed, use of maintenance immunosuppression, and the inclusion of other histological classes of lupus nephritis for analysis. The long-term outcome of DPLN in our southern Chinese patients is better than that of the African Americans in whom a 5-year renal survival rate of 57% was reported despite treatment with intravenous pulse CYC. 21 In a more recent study that consisted mainly of Hispanic and African Americans, the renal survival at 6 years for those treated with intravenous pulse CYC was consistently poor at a rate of less than 50%. 22 In most previous studies, either the direct proportion or the cumulative percentages of patients with renal failure were reported. These figures were likely to be influenced by the sample size (number of patients remaining in the cohort) and the variability in the duration of follow-up. We therefore reported the actual incidence of various outcomes per 1000 patient-years of follow-up to facilitate comparison with data from other ethnic groups in future studies. The optimal route, dosage, and duration of CYC administration in lupus nephritis remain inconclusive, partly because of the lack of large comparative studies. In the controlled trial conducted by the National Institutes of Health (NIH) in the 1980s, it was demonstrated that intravenous pulse CYC had a better long-term efficacy than continuous oral CYC, but the difference was not significant. 2 Subgroup analysis on those patients with DPLN was not available. A comparative study on 2 prospective cohorts with lupus nephritis treated with either continuous low dose CYC or intravenous pulse CYC in 2 centers demonstrated that at 6 and 24 months after treatment, the oral regimen tended to be more effective. 13 A definite conclusion cannot be drawn because of the limited sample size and the short duration of observation. In order to address the issue of whether the route of CYC administration may affect its efficacy in DPLN, randomized controlled trials with adequate power are needed. However, such studies are unlikely to emerge in the near future because the current trend has focused on the newer immunosuppressive agents such as MMF and the calcineurin inhibitors. Although not a randomized study, we demonstrated that complete response was more likely to occur with oral CYC than intravenous CYC treatment. However, statistical significance was lost in the multivariate model, indicating that the higher response rate of the oral regimen was related to its higher cumulative dose. The oral regimen also was associated with a better long-term composite outcome of creatinine doubling, ESRF, and mortality, but statistical significance could not be reached. Although this can still be due to the inadequate power of the current study to detect the observed difference, it is noteworthy that the cumulative doses of CYC administered by the intravenous pulse CYC regimen in our patients (mean 9.1 gram per patient) are lower than that in the standard NIH pulse CYC regimen. This is probably related to the poorer tolerability and the smaller body-build of our patients, as well as the inadequate dosing of CYC. Moreover, patients treated with intravenous bolus CYC were less likely to receive maintenance immunosuppression. All these might have contributed to the apparently lower efficacy observed in the pulse CYC regimen when compared with oral CYC. Relapse of nephritis is another important outcome in treatment trials of lupus nephritis. Although renal flares may respond completely to re-treatment with immunosuppressive agents, recurrent inflammation of the nephrons may cause further damage to renal function. The NIH investigators reported a high rate of renal flares after immunosuppression was stopped in a cohort of lupus nephritis patients participating in previous randomized controlled trials 23. Renal flares, in particular nephritic renal flares, are associated with a deterioration of renal function. 24 In our previous analysis of 155 patients who responded partially or completely to CYC, the occurrence of nephritic flares was an independent risk factor for doubling of serum creatinine. 14 However, the analysis did not take into account those patients who were recalcitrant to CYC therapy. As shown in the current results, these patients were at significant risk of having a poor renal outcome because many of them did not respond to re-induction treatment. As renal flares were defined as deterioration of renal parameters after a response was achieved, patients with refractory or persistent disease were not classified as having renal flares. With analysis of the whole cohort of patients, nephritic renal flare was not a significant predictor of the composite outcome of creatinine doubling, ESRF, and mortality. However, it was demonstrated that maintenance immunosuppression for a period of no less than 3 years was associated with a better long-term outcome. This was independent of the route of CYC administration, cumulative doses of CYC, and the initial renal parameters. As the use of maintenance immunosuppression was based on the preference of physicians, this finding has to be confirmed with future randomized controlled trials.

8 355.e32 The American Journal of Medicine, Vol 119, No 4, April 2006 Oral CYC IV CYC Probability of not having an event Log rank test: p= Time (months) No. remaining Figure Event-free survival of the composite outcome of creatinine doubling, end-stage renal failure, and death in the 212 patients studied Few studies have compared the toxicities of CYC with regard to the route of administration in lupus nephritis. In the NIH study, it was demonstrated that the intravenous CYC regimen was associated with a lower incidence of amenorrhea, hemorrhagic cystitis, and malignancy when compared with oral CYC. 2 A recent controlled trial recruited 29 patients with lupus nephritis who were randomized into either low-dose oral CYC (2 mg/kg/day for 3 months, followed by oral prednisolone and AZA) or intermittent pulse CYC (initially intravenous, then followed by oral pulses and pulse methylprednisolone). 25 The shortterm efficacy and the incidence of hemorrhagic cystitis, amenorrhea, and infection rate were not significantly different between the 2 regimens. Given the sample size of the study, an equivocal result is not unexpected. In accordance with our findings, gastrointestinal disturbance is more common with intermittent administration of high dose CYC. Ovarian toxicity of CYC is a major concern in the treatment of severe lupus nephritis because most patients are of childbearing age. The incidence of permanent amenorrhea after CYC therapy was reported to be 23% to 54% in various studies In a previous study of 70 SLE patients treated with CYC for various indications, we demonstrated that increasing age and the cumulative dose of CYC were independent risk factors for sustained amenorrhea. 29 As only a small proportion of patients had received intravenous CYC, the effect of the route of CYC administration on ovarian toxicity was not apparent. Moreover, the cumulative dose of CYC with respect to body weight was not examined. In the current study, which consisted of a much larger cohort of patients with a roughly equal proportion treated with either intravenous or oral CYC, it was consistently shown that increasing age and cumulative doses of CYC per unit of body weight (rather than the route of CYC administration) were independent risk factors of ovarian failure. For patients at risk of sustained amenorrhea, a shorter course of CYC or the concomitant use of gonadotropinreleasing hormone (GnRH) analogues 30 should be considered. Alternative options such as MMF and the calcineurin inhibitors should also be considered in selected patients with more favorable prognostic factors. In conclusion, we have demonstrated in our cohort of Chinese patients with DPLN that cumulative doses, rather than the route of CYC administration, determined the initial treatment response and ovarian toxicity. The use of maintenance immunosuppression is associated with a better long-term preservation of renal function, regardless of the initial route of CYC administration. The oral CYC regimen is more toxic and should be reserved for high-risk patients and those with refractory lupus nephritis. References 1. Mok CC, Wong RWS, Lai KN. Treatment of severe proliferative lupus nephritis: the current state. Ann Rheum Dis. 2003;62: Austin HA III, Klippel JH, Balow JE, et al. 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