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Efficacy of abatacept treatment for focal segmental glomerulosclerosis and minimal change disease: A systematic review of case reports, case series, and observational studies .

INTRODUCTION
The efficacy of abatacept has been demonstrated mainly in case reports, case series, and observational studies with small sample size. With current evidence, it is premature to conclude that abatacept is an effective treatment for nephrotic syndrome.


MATERIALS AND METHODS
We searched MEDLINE, SCOPUS, and Cochrane Library until December 2019 for studies including patients with focal segmental glomerulosclerosis (FSGS) or minimal change disease (MCD) treated with abatacept. Proteinuria recovery and remission were outcomes of interest. Presence of urinary CD80 level of B7-1 staining on kidney biopsies was also reported.


RESULTS
A total of 11 studies (n = 32) were included in the systematic review. 60% of patients were male. The median age was 27.5 years (range 5.2 - 72 years). Approximately 90.6% had FSGS, while 9.4% had MCD. With median follow-up of 12 months (IQR 6.38), only 15 patients (46.9%) showed response in proteinuria reduction, and 12 patients (43.8%) achieved remission with abatacept. Serious adverse events were reported in 12.5%. Additionally, we observed that patients with positive B7-1 staining on kidney biopsies had higher odds of achieving remission with abatacept (likelihood ratio 18.25; p < 0.001). We found no significant correlation between elevated CD80 levels and remissions.


CONCLUSION
The efficacy of abatacept therapy for FSGS or MCD was only 43.8%. Serious adverse effects are common. However, our study suggested that abatacept should be considered only in patients with positive B7-1 staining on kidney biopsy because these patients tend to respond to treatment. .