Cyclophosphamide treatment for hypertension and renal injury in an experimental model of systemic lupus erythematosus

Cardiovascular disease is the major cause of mortality among patients with the autoimmune disorder systemic lupus erythematosus (SLE). Our laboratory previously reported that immunosuppression with mycophenolate mofetil, a common therapy in patients with SLE, attenuates the development of hypertension in an experimental model of SLE. Cyclophosphamide (CYC) is another common therapy for patients with SLE that has contributed to improved disease management; however, its impact on the development of hypertension associated with SLE is not clear. We tested whether treatment with CYC (25 mg/kg, once/week, IP injection) for 4 weeks would attenuate hypertension in an established female mouse model of SLE with hypertension (30-week-old NZBWF1 females). Plasma anti-dsDNA IgG levels, pathogenic for the disease, were lower in CYC-treated SLE mice compared to vehicle-treated SLE mice, suggesting efficacy of the therapy to suppress aberrant immune system function. Mean arterial pressure (MAP) was assessed by carotid artery catheters in conscious mice. Treatment did not attenuate the development of hypertension when compared to vehicle-treated SLE mice; however, urinary albumin excretion was lower in CYC-treated animals. Corresponding with the reduction in autoantibodies, data suggest that CYC treatment lowered circulating CD45R+ B cells. Paradoxically, circulating CD11b+ Ly6G+ neutrophils were increased in CYC-treated SLE mice compared to vehicle treated. Estrus cycling data also suggest that CYC treatment had an impact on ovarian function that may be consistent with reduced circulating estrogen levels. Taken together, these data suggest that CYC treatment attenuates autoantibody production and renal disease during SLE, but that the potential to affect MAP may be blunted by the increase in circulating neutrophils and CYC's impact on ovarian function.

Pharmacokinetics of mycophenolic acid in severe lupus nephritis

Mycophenolic acid (MPA) is an effective treatment for active lupus nephritis despite its variable efficacy in different ethnic groups. Here we tested whether pharmacokinetic monitoring may help to optimize dosing of MPA in an Asian population. Patients with biopsy-proven class III or IV lupus nephritis (ISN/RPS category) were treated with mycophenolate mofetil or enteric-coated mycophenolate sodium. One month after initiating treatment we measured plasma MPA levels in eight samples taken over a 12-h period after drug administration. The mean area under the time-dependent curve for MPA of responding patients was significantly higher than those not responding. Successful treatment was seen in patients with areas >45 mg h/l. The dosage of the drug was not related to MPA pharmacokinetics. In the mycophenolate mofetil group, however, MPA-area under the curve was positively, and significantly, correlated with trough or 1 h after dose concentrations and associated with a therapeutic response. Thus, our study shows that MPA pharmacokinetics were positively correlated with therapeutic responses of mycophenolate, suggesting that controlling the concentrations may improve its therapeutic efficacy in lupus nephritis. As the absorption and pharmacokinetic peak of enteric-coated tablets is slower, it is important to take different formulations into account when determining optimal MPA concentrations.

Mycophenolate mofetil as induction and maintenance therapy for lupus nephritis: rationale and protocol for the randomized, controlled Aspreva Lupus Management Study (ALMS)

The Phase III Aspreva Lupus Management Study (ALMS) will investigate mycophenolate mofetil (MMF) therapy for lupus nephritis (LN). Eligibility criteria include: 12-75 years of age; diagnosis of systemic lupus erythematosus according to revised American College of Rheumatology criteria; and biopsy-demonstrated LN (Class III-V). Randomized patients will receive open-label induction therapy with MMF or cyclophosphamide in combination with corticosteroids for 24 weeks. The primary efficacy endpoint is treatment response [decreased proteinuria and stabilized (within 25% of baseline) or improved serum creatinine level]. Patients achieving response or complete remission (normalization of all parameters) will be rerandomized to double-blind, placebo-controlled maintenance treatment with MMF or azathioprine, both plus corticosteroids. The maintenance phase primary endpoint is time to treatment failure. To detect a 15% rate improvement in the MMF group compared with cyclophosphamide, and to provide 90% power, a total of 358 patients will be required for the induction phase. On the basis of a projected 278 rerandomized patients, the maintenance phase will have 90% power to detect a difference between treatment groups assuming azathioprine and MMF three-year failure rates of 59.5% and 40.7%, respectively. Aspreva Lupus Management Study may provide invaluable comparative data on the efficacy and safety of MMF as LN induction and maintenance therapy.

Treatment of Proliferative Lupus Nephritis—A Critical Approach

OBJECTIVES

To discuss the current management of proliferative lupus nephritis (PLN), with a focus on strategies to improve long-term outcome and reduce treatment toxicity while minimizing the risk of relapse.

METHODS

The literature on treatment strategies used in systemic lupus erythematosus (SLE) and PLN from 1975 to 2006, using PubMed from the National Library of Medicine, was reviewed.

RESULTS

The high efficacy of the standard therapeutic regimen of PLN, traditionally associating cyclophosphamide (CYC) with corticosteroids (CS), has markedly ameliorated the prognosis of the disease, with more than 80% of patients achieving complete or partial remission. The ameliorated renal prognosis has positively influenced the general survival rates. Ten-year survival rates now surpass 75% and continue to improve. In view of the improved survival, the major aims of treatment now include preventing long-term organ damage and minimizing treatment toxicity, which can contribute significantly to the chronic morbidity and mortality of lupus. A number of high-quality trials have been reported, making us more confident of the value of different immunosuppressive protocols, and several novel immunosuppressive drugs are still under investigation.

CONCLUSION

Recent basic and clinical research has enormously improved our understanding of the pathogenesis of SLE and has suggested new, targeted approaches to therapy. These targeted novel therapies are expected to help the patients with PLN in the next decade.