The Evolving Role of Calcineurin Inhibitors in Treating Lupus Nephritis

The overall kidney survival among lupus nephritis patients has improved with currently used induction immunosuppression regimens of corticosteroids and either cyclophosphamide or mycophenolate mofetil; however, there still remains a significant number of lupus nephritis patients who do not achieve remission with these regimens. Investigators have looked at other immunosuppressive regimens for lupus nephritis, and there has been interest in the use of calcineurin inhibitors in this regard. Calcineurin inhibitors are potentially an attractive option because of their established ability to inhibit T cell function, attenuate proteinuria through non-immunologic means, and their safety in pregnancy and lactation. In this review, we discuss the findings and limitations of selected trials that evaluated the use of calcineurin inhibitors in the treatment of lupus nephritis, either with corticosteroids alone or as a component of multitarget therapy when combined with mycophenolate mofetil. There may be a role for calcineurin inhibitors among patients with heavy proteinuria, as well as younger patients with refractory lupus nephritis. The multitarget therapy trials reveal higher rates of remission compared with mycophenolate mofetil alone and cyclophosphamide; however, some trials highlight the possibility of more infectious adverse events. We discuss the need for further study of calcineurin inhibitors in more diverse patient populations and the need for trials with longer follow-up with "hard" endpoints beyond proteinuria reduction, such as worsening CKD or repeat protocol biopsies, given the calcineurin inhibitors ability to reduce proteinuria non-immunologically and thus increased rate of relapse when the drug is tapered. While there may indeed be a space for calcineurin inhibitors to help increase remission rates in lupus nephritis patients, more work is needed to help address the questions the studies available to date have yet to answer.