Method: Data from the standard of care arms of 5 industry sponsored clinical trials (Total N=620) were combined to estimate response rates by background medication at different time points during follow up. Response was defined as an improvement by at least 1 step in any BILAG A and B at baseline without any new BILAG A. Background medications were classified into the following five groups: azathioprine (AZA), mycophenolate mofetil (MMF), methotrexate (MTX), cyclophosphamide (IVC), and other (including treatments such as antimalarials alone); corticosteroids usage was calculated for each treatment group. Separate subgroup analyses were also performed of nephritis patients only. The chi-square test was used to evaluate the null hypothesis that response rates are equivalent across treatment groups.
Result: Estimated response rates across background treatment groups ranged from 34%–65% at 12 weeks (p=0.06) and 28%–52% at 52 weeks (p=0.05). At both time points, the lowest response rate occurred in the MTX group. Mean steroid doses were 12.3–23.5mg at 12 weeks and 8.2–13.3 mg at 52 weeks and were significantly lower in responders compared to non-responders at 52 weeks (p=0.01) but not at 12 weeks (p=0.68). When the lupus nephritis trials were analyzed separately, using a more stringent response definition that required improvement in renal BILAG scores to C or better, response rates were 21% on IVC and 26% on MMF at 12 weeks and 34% on IVC and 42% on MMF at 24 weeks, the maximum duration of follow-up.
Conclusion: Lupus patients enrolled in clinical trials and randomized to standard of care arms are a proxy for real-life experiences of lupus patients who receive these standard therapies. The results of these analyses therefore provide a basis both for expected outcomes of lupus patients receiving standard of care in clinical practice and for lupus subjects in clinical trials randomized to these therapies. In addition, these data may be useful for investigators designing future clinical trials.
Disclosure: K. C. Kalunian, UCB, 2, UCB,Genentech, 5 ; M. Kim, None; L. M. Hanrahan, None; J. C. P. Becker, BMS, 3 ; S. Bongardt, UCB, 3 ; P. Brunetta, Genentech/, 3 ; D. Close, MedImmune, 3 ; J. Drappa, MedImmune, 3, Genentech and Biogen IDEC Inc., 3 ; R. Furie, Genentech and Biogen IDEC Inc., BMS, 5, UCB, 2 ; B. H. Hahn, None; M. Linnik, Biogen Idec, 3 ; J. E. Salmon, None; N. Solomons, Vifor, 3 ; J. T. Merrill, None.