Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Analysis of the Use of Rituximab in the Treatment of Lupus Nephritis.

Croca1,  Sara C., Isenberg2,  David A.

Hospital de Santa Maria, Department of Medicine 1, Lisbon, Portugal
UCL Div of Medicine, London, United Kingdom

Background:

Lupus nephritis (LN) represents one of the most common and potentially severe complications of systemic lupus erythematosus (SLE). Classical serological markers of disease activity include the erythrocyte sedimentation rate (ESR) and the levels of anti-dsDNA antibodies and C3. Other serological markers with potential prognostic value such as the anti-ENA antibodies (ENAab) have also been studied. As traditional therapies show their limitations in achieving rapid disease control and damage prevention, novel treatment approaches have emerged. Rituximab (RTX) is an anti-CD20 monoclonal antibody that has been widely reported to be effective in treating renal disease flares. Our published data (Lu et al, Arthritis Rheum 2009) indicates that clinical benefit is related to the period of B-cell depletion. In this study we have analysed this period in detail, trying to determine if there are correlations to standard lupus tests and ethnicity.

Methods:

Between July 2001 and December 2009, 40 LN patients were treated with RTX at the University College Hospital London (UCLH). A minimum follow-up of 12 months was required for this study (n= 38). Patients were assessed at baseline and at 6 months after RTX in terms of serological and renal profile. Response to treatment was defined as an absolute CD19 count < 0.005 and values above this were considered evidence of repopulation.

Results:

Following the first RTX cycle, 89.47% (n= 34) were successfully depleted (CD19< 0.005). After 6 months, only 32.35% (n= 11) of these remained depleted. When comparing the depleted vs. the repopulated group, no differences were found in terms of the classical disease activity markers (ESR, anti-dsDNA and C3). Other serological markers such as the anti-C1q antibodies, ENAab and anti-cardiolipin antibodies also showed no association with depletion status. However, analysis of the ENAab subgroups showed that anti-Sm negative patients tend to remain depleted at 6 months. The baseline proteinuria and serum creatinine level also failed to influence response. In terms of ethnicity, Afro-caribbean origin patients were more likely to have repopulated at 6 months.

Conclusions:

In the last 10 years, RTX has progressively shown its potential as an effective drug in the treatment of SLE flares. However, its use in the context of LN is not as well documented. Despite the limitations imposed by the small size of our sample, a few interesting results have emerged. Renal disease background and classical disease activity markers did not predict response to treatment. Other serological markers such anti-C1q antibodies, anticardiolipine antibodies and ENAab status are also irrelevant. However, anti-Sm positive patients seem to be more likely to repopulate. In addition, AC patients tend to have higher rates of repopulation. Thus, classical serological markers are of no use in predicting response to RTX, apart from anti-Sm antibodies which may be associated with earlier repopulation. Finding predictors of response is important in order to select the patients more likely to respond and identify those with a probable shorter term response allowing for closer monitoring.

To cite this abstract, please use the following information:
Croca, Sara C., Isenberg, David A.; Analysis of the Use of Rituximab in the Treatment of Lupus Nephritis. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1144
DOI: 10.1002/art.28910

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