Circulating Anti-Rituximab Antibodies Do Not Affect Response to Rituximab in Steroid-Dependent Nephrotic Syndrome

Abstract

IntroductionNephrotic syndrome (NS) is the most common cause of proteinuria in children and young adults.1Noone D.G. Iijima K. Parekh R. Idiopathic nephrotic syndrome in children.Lancet. 2018; 392: 61-74https://doi.org/10.1016/S0140-6736(18)30536-1Abstract Full Text Full Text PDF PubMed Scopus (197) Google Scholar Steroids still represent the cornerstone of therapy for pediatric NS, achieving remission in 80% to 90% of the cases.S1 However, half of the patients develop relapses and require chronic steroid therapy to maintain remission (steroid-dependent NS, [SDNS]).S2Rituximab is a mouse-human chimeric monoclonal antibody targeting the CD20 antigen expressed on B cellsS3 and represents first-line steroid-sparing agent in complicated NS.2Kidney Disease: Improving Global Outcomes (KDIGO) Glomerular Diseases Work GroupKDIGO 2021 clinical practice guideline for the management of glomerular diseases.Kidney Int. 2021; 100: S1-S276https://doi.org/10.1016/j.kint.2021.05.021Abstract Full Text Full Text PDF PubMed Scopus (164) Google ScholarOwing to its chimeric nature, the immunogenicity of rituximab was reported in several diseases, such as rheumatoid arthritis and systemic lupus erythematosus.S4–S6 Recent findings have reported that the development of anti-rituximab antibodies may affect the efficacy of rituximab in children with SDNS3Fujinaga S. Nishino T. Endo S. Umeda C. Watanabe Y. Nakagawa M. Unfavorable impact of anti-rituximab antibodies on clinical outcomes in children with complicated steroid-dependent nephrotic syndrome.Pediatr Nephrol. 2020; 35: 2003-2008https://doi.org/10.1007/s00467-020-04629-wCrossref PubMed Scopus (7) Google Scholar and in adults with idiopathic membranous nephropathy.4Boyer-Suavet S. Andreani M. Lateb M. et al.Neutralizing anti-rituximab antibodies and relapse in membranous nephropathy treated with rituximab.Front Immunol. 2020; 10: 3069https://doi.org/10.3389/fimmu.2019.03069Crossref PubMed Scopus (31) Google ScholarHowever, the impact of anti-rituximab antibodies on the safety/efficacy of further infusions in SDNS still has to be fully elucidated.4Boyer-Suavet S. Andreani M. Lateb M. et al.Neutralizing anti-rituximab antibodies and relapse in membranous nephropathy treated with rituximab.Front Immunol. 2020; 10: 3069https://doi.org/10.3389/fimmu.2019.03069Crossref PubMed Scopus (31) Google Scholar,5Wincup C. Menon M. Smith E. et al.Presence of anti-rituximab antibodies predicts infusion-related reactions in patients with systemic lupus erythematosus.Ann Rheum Dis. 2019; 78: 1140-1142https://doi.org/10.1136/annrheumdis-2019-215200Crossref PubMed Scopus (23) Google Scholar,S7,S8 We aimed to evaluate the development of anti-rituximab antibodies in a cohort of patients with SDNS treated with rituximab as part of a large randomized controlled trial6Ravani P. Colucci M. Bruschi M. et al.Human or chimeric monoclonal anti-CD20 antibodies for children with nephrotic syndrome: a superiority randomized trial.J Am Soc Nephrol. 2021; 32: 2652-2663https://doi.org/10.1681/ASN.2021040561Crossref PubMed Scopus (12) Google Scholar and to establish the association between these antibodies and safety/efficacy of further rituximab administrations and B-cell depletion and reconstitution.ResultsPopulation CharacteristicsA total of 140 patients with SDNS were included in the study, and 64 of 140 had previously received at least 1 infusion of rituximab (average of previous infusions: 1.5 ± 0.7) in a median of 36 (13–54) months before enrollment. The closest infusion was 13 months before enrollment. Furthermore, 54 of 70 patients (77%) enrolled in the rituximab arm consented to participate to this ancillary study (Supplementary Figure S1).Detection of Anti-Rituximab Antibodies Before (T0) and 6 Months (T6) After Rituximab TreatmentAnti-rituximab antibodies were detected in none of the 64 patients receiving ≥1 infusions before enrollment. At 6 months, anti-rituximab antibodies were detected in 14 of 54 patients (26%) who received rituximab (Supplementary Figure S2A). Rituximab infusions before enrollment did not affect the development of anti-rituximab antibodies at T6 (Supplementary Figure S2B). There were no differences in the baseline characteristics (Supplementary Table S1).Relapse and Anti-Rituximab AntibodiesOf 54 patients treated with rituximab, 35 (65%) relapsed during the 24 months of follow-up. Incidence of anti-rituximab antibodies at 6 months postrandomization was not statistically different between patients who relapsed versus who did not (Supplementary Figure S2C). Time to relapse is reported in Figure 1a . We also compared time to relapse in patients developing anti-rituximab antibodies with subjects randomized to ofatumumab in the original trial (Figure 1b).The relapse rate was not statistically different between patients with (7/14, 50%) and without (28/40, 70%) anti-rituximab antibodies (Supplementary Figure S3A). According to the protocol study, the 35 relapsing received a further infusion of rituximab at each relapse: 23 of 35 experienced 2 or more relapses (2 or more rituximab infusions after enrollment) and 12 of 35 (34%) had only 1 relapse after enrollment (only 1 rituximab infusion after enrollment). In the 35 relapsing patients who received further rituximab doses, presence of anti-rituximab antibodies at 6 months of follow-up did not correlate with incidence of further relapses (Supplementary Figure S3B).Impact of Anti-Rituximab Antibodies on Circulating Total and Memory B Cells Post-Rituximab TreatmentWe measured changes in B-cell subsets in 33 patients (10 and 23 from the anti-rituximab antibodies positive and negative subjects, respectively). Patients with and without anti-rituximab antibodies had similar level of total B-cell count before rituximab therapy. At months 6 and 12 after rituximab, both groups had similar B-cell reconstitution (Figure 2a ). Similar results were reported for memory B cells (Figure 2b).Figure 2Reconstitution of total and memory B cells is not affected by the development of anti-rituximab antibodies. (a) Total B-cell counts at month 6 and at month 12 had similar reconstitution in patients with (n = 10) and without (n = 23) anti-rituximab antibodies at T6, with nonsignificant statistical differences. (b) Memory B-cell counts at month 6 and at month 12 had similar reconstitution in patients with and without anti-rituximab antibodies at T6, with nonsignificant statistical differences. ∗ refers to T0; # refers to T6. Abs, antibodies; neg, negative; pos, positive; RTX, rituximab.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Of note, time to relapse and B-cell reconstitution were not statistically different even considering only subjects with serum levels of anti-rituximab antibodies above the manufacturer threshold of 5 ng/ml (not found).SafetyAll the 54 participants remained free from severe complications during the entire duration of the study. Moreover, none of the subjects reported infusion-related reactions.DiscussionIn this study, we investigated the development of anti-rituximab antibodies and their association with clinical outcome in subjects with SDNS. In accordance with previous reports,3Fujinaga S. Nishino T. Endo S. Umeda C. Watanabe Y. Nakagawa M. Unfavorable impact of anti-rituximab antibodies on clinical outcomes in children with complicated steroid-dependent nephrotic syndrome.Pediatr Nephrol. 2020; 35: 2003-2008https://doi.org/10.1007/s00467-020-04629-wCrossref PubMed Scopus (7) Google Scholar,7Albert D. Dunham J. Khan S. et al.Variability in the biological response to anti-CD20 B cell depletion in systemic lupus erythaematosus.Ann Rheum Dis. 2008; 67: 1724-1731https://doi.org/10.1136/ard.2007.083162Crossref PubMed Scopus (168) Google Scholar we found that 26% of patients developed anti-rituximab antibodies.Bertrand et al.8Bertrand Q. Mignot S. Kwon T. et al.Anti-rituximab antibodies in pediatric steroid-dependent nephrotic syndrome.Pediatr Nephrol. 2022; 37: 357-365https://doi.org/10.1007/s00467-021-05069-wCrossref PubMed Scopus (3) Google Scholar recently described development of anti-rituximab antibodies in 7 of 24 patients receiving single infusion (375 mg/m2) in children with frequent-relapsing or SDNS. Moreover, in a retrospective study, Boyer-Suavet et al.4Boyer-Suavet S. Andreani M. Lateb M. et al.Neutralizing anti-rituximab antibodies and relapse in membranous nephropathy treated with rituximab.Front Immunol. 2020; 10: 3069https://doi.org/10.3389/fimmu.2019.03069Crossref PubMed Scopus (31) Google Scholar described 44 patients affected by membranous nephropathy and treated with two 1 g infusions of rituximab at 2-week interval, which developed anti-rituximab antibodies in 23% of cases at 6 months of follow-up.In the 24 months of follow-up, development of anti-rituximab antibodies in SDNS was not associated with increased risk of disease recurrence after rituximab treatment. Therefore, in contrast to previous studies in other diseases such as systemic lupus erythematosus or membranous nephropathy, we did not find unfavorable outcomes after additional rituximab doses.4Boyer-Suavet S. Andreani M. Lateb M. et al.Neutralizing anti-rituximab antibodies and relapse in membranous nephropathy treated with rituximab.Front Immunol. 2020; 10: 3069https://doi.org/10.3389/fimmu.2019.03069Crossref PubMed Scopus (31) Google Scholar,5Wincup C. Menon M. Smith E. et al.Presence of anti-rituximab antibodies predicts infusion-related reactions in patients with systemic lupus erythematosus.Ann Rheum Dis. 2019; 78: 1140-1142https://doi.org/10.1136/annrheumdis-2019-215200Crossref PubMed Scopus (23) Google Scholar The lower rituximab doses in patients with SDNS compared with those used to treat individuals with systemic lupus erythematosus or membranous nephropathy may partially explain the inconsistency with previous studies using higher rituximab doses.4Boyer-Suavet S. Andreani M. Lateb M. et al.Neutralizing anti-rituximab antibodies and relapse in membranous nephropathy treated with rituximab.Front Immunol. 2020; 10: 3069https://doi.org/10.3389/fimmu.2019.03069Crossref PubMed Scopus (31) Google Scholar,5Wincup C. Menon M. Smith E. et al.Presence of anti-rituximab antibodies predicts infusion-related reactions in patients with systemic lupus erythematosus.Ann Rheum Dis. 2019; 78: 1140-1142https://doi.org/10.1136/annrheumdis-2019-215200Crossref PubMed Scopus (23) Google Scholar,8Bertrand Q. Mignot S. Kwon T. et al.Anti-rituximab antibodies in pediatric steroid-dependent nephrotic syndrome.Pediatr Nephrol. 2022; 37: 357-365https://doi.org/10.1007/s00467-021-05069-wCrossref PubMed Scopus (3) Google Scholar Therefore, the development of anti-rituximab antibodies may have a dose-dependent mechanism. However, the optimum dosing schedule for rituximab has not been established for NS.9Chan E.Y. Yu E.L.M. Angeletti A. et al.Long-term efficacy and safety of repeated rituximab to maintain remission in idiopathic childhood nephrotic syndrome: an international study.J Am Soc Nephrol. 2022; 33: 1193-1207https://doi.org/10.1681/ASN.2021111472Crossref PubMed Scopus (3) Google Scholar Some previous studies reported that a single dose of 375 mg/m2 would have comparable outcomes to higher doses in reducing the frequency of relapse and time to B-cell reconstitution.S9,S10 Therefore, our findings suggest that single low dose may also limit the development of anti-rituximab antibodies.Moreover, in contrast to previous findings,4Boyer-Suavet S. Andreani M. Lateb M. et al.Neutralizing anti-rituximab antibodies and relapse in membranous nephropathy treated with rituximab.Front Immunol. 2020; 10: 3069https://doi.org/10.3389/fimmu.2019.03069Crossref PubMed Scopus (31) Google Scholar,8Bertrand Q. Mignot S. Kwon T. et al.Anti-rituximab antibodies in pediatric steroid-dependent nephrotic syndrome.Pediatr Nephrol. 2022; 37: 357-365https://doi.org/10.1007/s00467-021-05069-wCrossref PubMed Scopus (3) Google Scholar,S11 we found low serum titers of circulating anti-rituximab antibodies, which may in part explain the lack of correlation between development of anti-rituximab antibodies and clinical outcome.Importantly, incidence of relapse in patients developing anti-rituximab antibodies and in subjects receiving ofatumumab was comparable.Depletion levels and the recovery of circulating total and memory B cells after rituximab were not affected by the presence of anti-rituximab antibodies. Previous retrospective studies presented contrasting results. Bertrand et al.8Bertrand Q. Mignot S. Kwon T. et al.Anti-rituximab antibodies in pediatric steroid-dependent nephrotic syndrome.Pediatr Nephrol. 2022; 37: 357-365https://doi.org/10.1007/s00467-021-05069-wCrossref PubMed Scopus (3) Google Scholar revealed that anti-rituximab antibodies were associated with incomplete CD19+CD20− B-cell depletion and low serum rituximab levels in SDNS. However, the development of anti-rituximab antibodies was not associated with shorter B-cell depletion. In contrast, in children with SDNS receiving single dose of rituximab (375 mg/m2), the median time of B-cell recovery was significantly shorter in 9 of 13 developing anti-rituximab antibodies.3Fujinaga S. Nishino T. Endo S. Umeda C. Watanabe Y. Nakagawa M. Unfavorable impact of anti-rituximab antibodies on clinical outcomes in children with complicated steroid-dependent nephrotic syndrome.Pediatr Nephrol. 2020; 35: 2003-2008https://doi.org/10.1007/s00467-020-04629-wCrossref PubMed Scopus (7) Google Scholar Difference in rituximab doses and anti-rituximab antibody levels may explain inconsistencies in the impact of anti-rituximab antibodies across studies.We also reported that, at randomization, anti-rituximab antibodies were negative in all patients who previously received at least 1 infusion of rituximab. This suggests that the persistence of serum anti-rituximab antibodies is temporary, although serial measurement is required to substantiate this hypothesis.Rituximab is generally well tolerated, with adverse events mostly limited to infusion reactions.S12 Previous studies have reported a possible correlation between the incidence of infusion-related reactions and anti-rituximab antibodies,4Boyer-Suavet S. Andreani M. Lateb M. et al.Neutralizing anti-rituximab antibodies and relapse in membranous nephropathy treated with rituximab.Front Immunol. 2020; 10: 3069https://doi.org/10.3389/fimmu.2019.03069Crossref PubMed Scopus (31) Google Scholar,5Wincup C. Menon M. Smith E. et al.Presence of anti-rituximab antibodies predicts infusion-related reactions in patients with systemic lupus erythematosus.Ann Rheum Dis. 2019; 78: 1140-1142https://doi.org/10.1136/annrheumdis-2019-215200Crossref PubMed Scopus (23) Google Scholar,S13 but data are inconsistent.S5 In this study, we did not report any adverse event nor infusion-related reactions in subjects presenting anti-rituximab antibodies.The prospective design represents a major strength of this work. In addition, considering SDNS is a rare condition, we present data on a large cohort of subject. We also recognize some limitations: not all patients assigned to the rituximab arm consented to participate to the ancillary study, we performed only a single detection of anti-rituximab antibodies at 6 months of follow-up, and B-cell analysis was performed on 33 of 54 subjects, but there was no bias in the selection of patients because all were asked to participate.In conclusion, we found that approximately one-fourth of patients with SDNS develop anti-rituximab antibodies after a single rituximab infusion. The presence of these antibodies does not affect the safety/efficacy profile of rituximab in this population nor circulating B-cell kinetics.DisclosureThe authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. IntroductionNephrotic syndrome (NS) is the most common cause of proteinuria in children and young adults.1Noone D.G. Iijima K. Parekh R. Idiopathic nephrotic syndrome in children.Lancet. 2018; 392: 61-74https://doi.org/10.1016/S0140-6736(18)30536-1Abstract Full Text Full Text PDF PubMed Scopus (197) Google Scholar Steroids still represent the cornerstone of therapy for pediatric NS, achieving remission in 80% to 90% of the cases.S1 However, half of the patients develop relapses and require chronic steroid therapy to maintain remission (steroid-dependent NS, [SDNS]).S2Rituximab is a mouse-human chimeric monoclonal antibody targeting the CD20 antigen expressed on B cellsS3 and represents first-line steroid-sparing agent in complicated NS.2Kidney Disease: Improving Global Outcomes (KDIGO) Glomerular Diseases Work GroupKDIGO 2021 clinical practice guideline for the management of glomerular diseases.Kidney Int. 2021; 100: S1-S276https://doi.org/10.1016/j.kint.2021.05.021Abstract Full Text Full Text PDF PubMed Scopus (164) Google ScholarOwing to its chimeric nature, the immunogenicity of rituximab was reported in several diseases, such as rheumatoid arthritis and systemic lupus erythematosus.S4–S6 Recent findings have reported that the development of anti-rituximab antibodies may affect the efficacy of rituximab in children with SDNS3Fujinaga S. Nishino T. Endo S. Umeda C. Watanabe Y. Nakagawa M. Unfavorable impact of anti-rituximab antibodies on clinical outcomes in children with complicated steroid-dependent nephrotic syndrome.Pediatr Nephrol. 2020; 35: 2003-2008https://doi.org/10.1007/s00467-020-04629-wCrossref PubMed Scopus (7) Google Scholar and in adults with idiopathic membranous nephropathy.4Boyer-Suavet S. Andreani M. Lateb M. et al.Neutralizing anti-rituximab antibodies and relapse in membranous nephropathy treated with rituximab.Front Immunol. 2020; 10: 3069https://doi.org/10.3389/fimmu.2019.03069Crossref PubMed Scopus (31) Google ScholarHowever, the impact of anti-rituximab antibodies on the safety/efficacy of further infusions in SDNS still has to be fully elucidated.4Boyer-Suavet S. Andreani M. Lateb M. et al.Neutralizing anti-rituximab antibodies and relapse in membranous nephropathy treated with rituximab.Front Immunol. 2020; 10: 3069https://doi.org/10.3389/fimmu.2019.03069Crossref PubMed Scopus (31) Google Scholar,5Wincup C. Menon M. Smith E. et al.Presence of anti-rituximab antibodies predicts infusion-related reactions in patients with systemic lupus erythematosus.Ann Rheum Dis. 2019; 78: 1140-1142https://doi.org/10.1136/annrheumdis-2019-215200Crossref PubMed Scopus (23) Google Scholar,S7,S8 We aimed to evaluate the development of anti-rituximab antibodies in a cohort of patients with SDNS treated with rituximab as part of a large randomized controlled trial6Ravani P. Colucci M. Bruschi M. et al.Human or chimeric monoclonal anti-CD20 antibodies for children with nephrotic syndrome: a superiority randomized trial.J Am Soc Nephrol. 2021; 32: 2652-2663https://doi.org/10.1681/ASN.2021040561Crossref PubMed Scopus (12) Google Scholar and to establish the association between these antibodies and safety/efficacy of further rituximab administrations and B-cell depletion and reconstitution.

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