Reasons why women with lupus change from azathioprine to mycophenolate mofetil or vice versa are different, as is the success of switching.
Al Maimouni H, Gladman DD, IbaÃ±ez D, Uroitz MB. Switching treatment between mycophenolate mofetil and azathioprine in lupus patients: Indications and outcomes.Arthritis Care & Research (2014) doi: 10.1002/acr.22364 [Accepted Manuscript] May 12, 2014
Patients with systemic lupus erythematosus (SLE) switch from azathioprine (AZA) to mycophenolate mofetil (MMF) most often due to AZA failure and renal disease, while they usually change from MMF for AZA due to MMF’s side effects and a desire to become pregnant, according to Canadian researchers.
The study of 92 SLE patients from the University of Toronto Lupus Clinic database finds that when a change is made due to drug failure, disease activity improves after six months and patients are able to reduce their dose of corticosteroids.
On the other hand, when patients switch because of adverse side effects, a desire to become pregnant, for financial reasons, or because they need a kidney transplant for lupus nephritis (LN), there appears to be no corresponding decline in disease activity.
For most patients who had side effects, they resolved within six months.
AZA and MMF are the two most common maintenance therapies for SLE and LN. Previous studies show they have a similar prognosis, but MMF appears to be safer over the long-term in LN.
There are no guidelines for treating SLE and LN beyond three years, so researchers followed patients seen at the Toronto clinic between 2001 (when MMF first became available) and 2012. Most were white women who’d had lupus for around 9 years before they switched therapy; all were on steroids at the time.
Of the 92 patients who changed maintenance drugs within a six-month period, 89 switched from AZA to MMF, most citing drug failure and disease flares. Around half had renal flares and two needed a transplant.
Far fewer, only 19, switched from MMF to AZA, almost half because of side effects, the rest due to drug failure and flares. A third wanted to become pregnant.
Adding to the guidelines may not be required: Given the variety of reasons for changing drugs and the significant improvement in disease activity when the reason was drug failure, the researchers conclude that lupus therapy lasting longer than three years needs to be individualized in any case.