Background/Purpose: Poor therapeutic response rates contribute to the increased morbidity and mortality associated with lupus nephritis. Early identification of patients likely to respond is crucial as delays in treatment associate with worse outcomes. This study evaluated response using prospectively collected data obtained from the multi-ethnic/racial, multi-center Accelerating Medicines Partnership (AMP) lupus nephritis cohort. This cohort represents a real-world clinical setting using provider chosen standard of care and uniform collection of data.

Methods: This study included SLE patients based on ACR or SLICC classification enrolled in AMP who met the following criteria: urine protein-creatine ratio (UPCR) > 1 at entry, and histologic biopsy Class III, IV, V, or mixed. Patients were followed at 3, 12, 26 and 52 wks with demographics, history, laboratory results, disease activity, and medications recorded at each visit. Follow up data were available for 136 patients at 26 wks and 118 at 52 wks. Complete response was defined as a reduction in UPCR to < .5, a normal serum creatinine or no greater than 125% of baseline, and < 10 mg prednisone at time of response assessment. Patients were partial responders if UPCR decreased > 50% but remained >.5 and nonresponders if < 50% reduction in UPCR and/or did not meet the other response criteria.

Results: Medications were reported at 12 wks (Table 1). The complete response rate was 26% at both 26 and 52 wks. For patients undergoing a first biopsy, the rates were 37% and 40% and for those with repeat biopsies, the rates were lower at 21% and 19% respectively (p=0.042 at 26 wks; p=0.015 at 52 wks). The complete response at 26 wks was generally sustained with only 4 of 27 patients experiencing a relapse at 52 wks. At 26 wks, patients with membranous histology were less likely to be complete responders than patients with proliferative histology.

This trend was observed regardless of biopsy number and persisted for response status at 52 wks. Although baseline activity score did not predict responder status, complete responders had a significantly lower chronicity index than nonresponders (mean + SD, 2.26 + 2.22 vs 3.83 + 2.57, p=0.016) at 26 wks with similar results at 52 wks. Responder status at 26 and 52 wks whether first or repeat biopsy was independent of extrarenal disease at entry (Table 2). Complete responder status was associated with positive anti-dsDNA serology at baseline for repeat biopsy patients. Complete responders had a greater change in C3, hemoglobin, lymphocyte count, albumin, and UPCR at 12 wks compared to baseline values than nonresponders (Table 3). Similar trends were observed when considering response status at 52 wks.

Conclusion: The low complete response rates reported in the AMP cohort are consistent with findings in blinded controlled trials of standard-of-care therapies and support the critical need for new therapeutics particularly in patients undergoing repeat biopsies and those with increased chronicity.

Table 1: Medications received at 12 weeks by responder status. 2-way p-values compare nonresponders to complete responders

Table 2: Baseline characteristics by response status at 26 weeks. 2-way p-values compare nonresponders to complete responders. *Excludes points for low complement, anti-dsDNA positivity, hematuria, pyuria, proteinuria, and casts

Table 3: Change in laboratory values at 12 weeks compared to baseline by response status. Data are presented as median [IQR], 2-way p-values compare nonresponders to complete responders. *Includes only patients who had low complement at baseline.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/renal-responder-status-and-associated-clinical-variables-in-the-lupus-accelerating-medicines-partnership-cohort/