Cyclophosphamide treatment in systemic necrotizing vasculitis and lupus nephritis. How long? How much?

The gold standard for inducing remission in systemic necrotizing vasculitis (SNV) and severe lupus nephritis is (and remains) the combination of cyclophosphamide and glucocorticoids. Long-term treatment with cyclophosphamide is limited because of toxicity. Recent prospective studies in antineutrophil cytoplasmic antibody (ANCA)-associated SNV revealed that after achievement of clinical remission (usually within 3–4 months after starting cyclophosphamide) cyclophosphamide can be replaced by azathioprine with no increase in relapse rates if treatment is continued for at least 1 year. Methotrexate is inferior to cyclophosphamide because of increased relapse rates—particularly in those with renal involvement—during follow-up. An ongoing study comparing mycophenolate mofetil (MMF) with azathioprine will clarify whether MMF is as successful as azathioprine or even better. The concomitant use of tumor necrosis factor (TNF)-α blockers increases the efficacy of immunosuppression. TNF-α blockers may be added if SNV is refractory to standard immunosuppressive therapy. However, with this addition to therapy, systemic infections are more frequent. In patients with severe lupus nephritis (WHO IV) the efficacy of combined i.v. therapy with cyclophosphamide and glucocorticoids was shown by NIH trials. This NIH regimen competes with the EURO-Lupus nephritis schedule with a lower dose of i.v. cyclophosphamide followed by maintenance therapy with azathioprine. Long-term follow-up is, however, still lacking in the EURO-Lupus trial. Ongoing prospective studies will reveal whether cyclophosphamide may be substituted by MMF from the very beginning or whether MMF is superior to azathioprine during maintenance therapy of lupus nephritis.