The primary outcome was a composite outcome of graft loss or absence of improvement of renal function at day 12. Because the 2 groups showed no graft loss at day 12, the primary outcome was defined by the absence of significant improvement in renal function at day 12. The primary outcome was observed in 52.6% (10/19) and 57.9% (11/19) of the rituximab and placebo groups, respectively (P = 0.744) (Figure 2A). The percentage decrease in serum creatinine level at day 12 was similar in the 2 groups (median [Q1; Q3] 20.5 [0.0; 47.1] vs 19.7 [8.6; 35.3], P = 1.00) (Figure 2B).
Patient And Graft Survival
No death occurred during the study period. One graft loss was observed in the placebo group at 6 months and 1 in the rituximab group at 12 months postacute AMR.
The rituximab and placebo groups did not differ in the number of patients who received supplementary rituximab (31.6% [6/19] vs 42.1% [8/19], P = 0.501) or total number of IVIg infusions (median [Q1; Q3] 9.0 [7.0; 13.0] vs 7.0 [6.0; 16.0], P = 0.761) or PE treatments (median [Q1; Q3], 7.0 [6.0; 9.0] vs 7.0 [6.0; 10.0], P = 0.924).
Both groups showed improved renal function, with significant decrease in median serum creatinine level during the study (−5.27; 95% confidence interval [95% CI] −10.30 to −0.24] μmol/L; P = 0.040), with no significant between-group differences (−25.24 μmol/L; 95% CI, −95.53 to 45.05; P = 0.480) (Figure 3). The decrease in serum creatinine was rapid and significant between day 0 and day 12 (82.79 μmol/L; 95% CI, 39.86-125.73; P = 0.0004) with no significant between-group differences. The median (Q1; Q3) serum creatinine level at 12 months for the rituximab and placebo groups was 157 (107; 224) and 158 (129; 217) μmol/L, respectively. The median estimated glomerular filtration rate (eGFR), calculated by the MDRD equation, was increased but not significantly during the study (0.06; 95% CI, −0.002 to 0.118] mL/min per 1.73 m2; P = 0.058), with no significant between-group differences (0.30; 95% CI, −0.56 to 1.16 mL/min per 1.73 m2; P = 0.495). At 12 months, the eGFR was greater than 30 mL/min per 1.73 m2 for 57.9% (11/19) versus 66.7% (12/18) for the rituximab and placebo groups, respectively (P = 0.833); the eGFR was greater than 60 mL/min per 1.73 m2 for only 10.5% (2/19) and 5.6% (1/18) of patients, respectively (P = 1.00). When comparing renal function at 12 months, the eGFR was greater than 30 mL/min per 1.73 m2 in 14 of 19 (73.7%) patients in whom acute AMR occurred within the first 3 months versus 6 of 16 (37.5%) in whom acute AMR occurred later (P = 0.031); the difference was more striking when we used a 45-mL/min per 1.73 m2 eGFR cutoff value: 7 of 19 (36.8%) versus 0 of 16 (0.0%) (P = 0.022). The rituximab and placebo groups did not differ in these 2 subgroups. The results were similar in per-protocol analyses (SDC, http://links.lww.com/TP/B205).
We found no significant decrease in median proteinuria during the study (−0.05; 95% CI, -0.12 to 0.02; P = 0.172), with no significant between-group differences (−0.73; 95% CI, −1.57 to 0.12; P = 0.090) (Figure 4). At 12 months, the rate of proteinuria less than 0.3 g/d for the rituximab and placebo groups was 66.7% (12/18) and 63.2% (12/19), respectively; the rate 0.3 to 1.0 g/d was 5.5% (1/18) and 26.3% (5/19); and the rate > 1.0 g/d was 27.8% (5/18) and 10.5% (2/19), with no significant difference between groups (P = 0.174). The results were similar in per-protocol analyses (SDC, http://links.lww.com/TP/B205).
Histological features of AMR improved at 1 month after treatment in both groups. Nevertheless, the rate of histological lesions of AMR persisted at both 1 month (47.1% [8/17] vs 50.0% [7/14], P = 0.871) and 6 months (31.3% [5/16] vs 41.7% [5/12], P = 0.569) in the rituximab and placebo groups, respectively.
The changes in Banff scores for acute and chronic histological features at 0, 1, and 6 months were similar between the rituximab and placebo groups, although with a significant decrease in microvascular inflammatory score (glomerulitis and peritubular capillaritis) at 6 months in the rituximab group and a significant increase in chronic injury (interstitial fibrosis and tubular atrophy) at 6 months in the placebo group (Table 2, Figures 5 and 6). C4d deposits in peritubular capillaries decreased in both groups after treatment, with no differences between groups. At 6 months, only 3 of 16 and 1 of 12 patients had histological features of transplant glomerulopathy in the rituximab and placebo groups, respectively. We did not find any difference in rate of chronic lesions between patients with acute AMR associated with cell-mediated rejection and those with acute AMR alone. The results were similar in per-protocol analyses (SDC, http://links.lww.com/TP/B205).
We found a rapid and significant decrease in median MFI of iDSAs during the study (−2.14; 95% CI, −3.23 to −1.05; P < 0.001), with no significant between-group differences (1.23; 95% CI, −18.21 to 20.67; P = 0.901) (Figure 7). The decrease in MFI of iDSAs was rapid and significant between days 0 and 12 (3580; 95% CI, 1960 to 5200], P < 0.0001) with no between-group differences. Nevertheless, MFI less than 1500 for the iDSAs was more frequent but not significantly in the rituximab than placebo group (9/13 [69.2%] vs 5/13 [38.5%], P = 0.11) at the last serum analysis of DSAs. The results were similar in per-protocol analyses (SDC, http://links.lww.com/TP/B205).
Change In Blood Cd19 B-Cell Count
For patients who received at least 1 rituximab injection, the blood CD19+ B cell count was low within 1 month (<5/mm3: 19/22), with a median of 1.0 (range, 0-62). At the end of follow-up (≥6 months), 60.0% (12/20) of patients still had CD19+ B-cell count less than 10/mm3.
In the per-protocol analysis, during the study, 37 serious adverse events were reported, 14 for patients receiving only placebo (corresponding to 7 patients), and 23 for patients receiving rituximab (corresponding to 16 patients) (Table 3). Infections were the most frequent serious adverse events, with more urinary tract infections in the placebo group and more opportunistic infections (cytomegalovirus infection, BK virus infection, nocardia) in the rituximab group. One suspected but unexpected serious adverse reaction, superficial spreading melanoma, was reported during the study in 1 patient who received rituximab.
In the RITUX-ERAH trial, a phase III, multicenter, double-blind, placebo-controlled RCT, the addition of rituximab to standard treatment for acute AMR in renal transplantation did not improve short-term outcomes for graft function as compared with placebo. At 1 year, we found no significant differences in renal function or iDSA MFI between the 2 groups, but the rituximab group showed a decrease, although not significant, in iDSA MFI.
The RITUX-ERAH trial is the largest RCT of AMR treatment in renal transplantation and the first to study its efficacy and safety. Only case series were previously reported, and a systematic review of acute AMR treatment published in October 2012 showed insufficient data to guide treatment.12,16-29,32 We showed that 1-year graft survival for AMR treated with IVIg, PE, and CS with or without rituximab was excellent, and we could not demonstrate a supplementary efficacy of rituximab by graft survival or our primary endpoint. An additional beneficial effect of PE and rituximab on graft survival was reported in a group of 12 patients receiving IVIg, PE, and rituximab (92%) as compared with a historical group of 12 patients receiving only IVIg (50%)29; however, the respective impact of PE and rituximab could not be assessed, especially because graft survival was observed in about 80% of patients receiving IVIg and PE treatment in the literature.33 A better, 2-year graft survival was reported for patients receiving rituximab and PE (80%) than that in a PE cohort (60%).28 However, this retrospective analysis compared 2 heterogeneous historical groups of patients with chronic and acute humoral rejection, with and without DSAs, and the rituximab group was more frequently supplemented with IVIg than the group receiving PE alone.
In contrast with the good graft survival at 1 year, both groups showed persistent histological lesions of AMR and microvascular inflammation, with increased chronic lesion score. The persistence of signs of AMR and microvascular inflammation associated with the development of chronic lesions in many patients could predict a poor long-term graft outcome, especially because we observed poor 1-year renal function in most patients, with an MDRD greater than 60 mL/min per 1.73 m2 in only 3 patients. However, the rituximab group showed a trend to less microvascular inflammation and fewer chronic lesions as compared with the placebo group.
Rituximab was developed to treat hematologic malignancies and was later used to treat antibody-dependant diseases, such as AMR. Rituximab induces a depletion of blood CD20+ B cells followed by reconstitution over subsequent months and reduces the number of these cells in spleen and lymph nodes.34 It has been used for treatment and/or prevention of AMR to abrogate or reduce the humoral response, in particular the production of de novo DSAs.35,36 Its efficacy, combined with PE and IVIg, has been demonstrated to prevent AMR35,37-40 perhaps because rituximab prevents an anamnestic response in patients with cryptic sensitization to HLA antigens.41 Nevertheless, rituximab does not have a direct effect on antibody-producing plasma cells, which could explain the lower results for established AMR treatment than that for AMR prevention. Interestingly, we observed a rapid and significant decrease in iDSAs as soon as day 12 with EP and IVIg but with no additional effect of rituximab. The AMR is a highly inflammatory process, and our results highlight the need to use more potent anti-inflammatory agents, such as eculizumab, in the acute phase42 to rapidly treat the microvascular injuries. In some patients, we observed patterns of T-cell–mediated rejection. In these mixed cellular rejections, the use of a T-cell–depleting agent could be considered, as previously proposed, and needs to be assessed in future trials.43 Nevertheless, as in autoimmunity, rituximab often takes a number of months to work; we noted that at 12 months, the number of patients with iDSAs less than 1 500 was more frequent in the rituximab group than the placebo group. Decreased microvascular inflammation was observed in the rituximab group between rejection and 6 months, and increased chronic lesions was significant only in the placebo group. The demonstrated role of DSAs in the progressive process of microvascular injury and late kidney transplant failure44-46 highlights the need for a more prolonged follow-up for testing the efficacy of AMR treatments.
The use of rituximab is associated with several complications.47 In our study, the patients who received rituximab more frequently had cytomegalovirus infection, BK virus infection, and gastrointestinal disorders than did other patients. These complications have been previously described and must be taken into account.
Our study has several limitations. The number of patients included was lower than the planned sample size because during the period, rituximab was largely used to prevent AMR at the time of transplantation and prior use of rituximab was an exclusion criteria. This reduced number of patients could have underpowered our study, particularly in terms of histopathology score and iDSAs, MFI showing trends toward a better outcome in the rituximab group. As our study was underpowered, important differences between groups may have been missed. For most patients, we used a single injection of rituximab instead of the 4 injections used for treatment of hematological malignancies. Nevertheless, all patients showed profound B-cell depletion over several weeks. Because the design allowed for a rescue injection of rituximab, the number of patients who received only placebo during the study was decreased, but in the per-protocol analysis, all the results were similar with the ITT analysis, regardless of renal function, Banff scores, or DSAs. We found no significant differences in DSAs between the 2 treatment groups, but new assays detecting pathogenic antibody-fixing complement have been developed since, and we cannot exclude a potential effect of rituximab on these antibodies. Finally, the primary endpoint only captured the short-term effect of the treatment, and a 1-year survey is perhaps too short. A longer follow-up of this cohort may be more informative, in particular because we observed fewer chronic lesions at 6 months in the rituximab than placebo group.
Despite these limitations, this trial remains the largest RCT of treatment of AMR. At 1 year follow-up, we observed no additional effect of rituximab. Nevertheless, our study was underpowered and complementary trials with long-term follow-up are needed.
The authors are very grateful to all the anatomic pathology laboratories (Machet Marie- Christine, François Arnaud, Rouvier Philippe, Pinel Nicole, Moreau Anne, Felix Sophie, Copin Marie-Christine, Bluod David, Comoz François, Desvaux Dominique, Deminiere Colette, Daniel Laurent, MacGregor Brigitte, Marcellin Luc, Raynaud Pierre, Funes de la Vega Mathilde, Dijoud Frederique, Paraf François, Saint-André Jean-Paul, Coure Anne, Noel Laure-Hélène, Nochy Dominique, Vuiblet Vincent, Birembaut Philippe, Cordonnier Carole) and HLA laboratories (Lever Laurent, Magdelaine Charlotte, Hau Françoise, Have Virgine, Zahr Noël, Masson Dominique, Devys Anne, Dupont Isabelle, Lablette Myriam, Toutirais Olivier, Suberbielle Caroline, Guidicelli Gwendaline, Basire Agnes, Dubois Valérie, Parissiadis Anne, Ramounau-Pigot Annie, Dautin Guillaume, Durand, Dominique, Faye Gaelle, Coeffic Brigitte, Lechaton Sophie, Tabary Thierry, Guillaume Nicolas) included in this study. We thank the members of the Center of Clinical Investigation of Tours (Nathalie Juteau, Bruno Giraudeau, Adeline Fourmy, Carinne Coffre and Estelle Boivin). The authors thank the Roche laboratory and the French Ministry of Health (PHRN07-YL RITUX-ERAH). The authors thank Laura Smales for copyediting.
1. Nankivell BJ, Alexander SI. Rejection of the kidney allograft. N Engl J Med
. 2010; 363: 1451–1462.
2. Solez K, Colvin RB, Racusen LC, et al. Banff 07 classification of renal allograft pathology: updates and future directions. Am J Transplant
. 2008; 8: 753–760.
3. Sis B, Mengel M, Haas M, et al. Banff '09 meeting report: antibody mediated graft deterioration and implementation of Banff Working Groups. Am J Transplant
. 2010; 10: 464–471.
4. Solez K, Racusen LC. The Banff classification revisited. Kidney Int
. 2013; 83: 201–206.
5. Almond PS, Matas A, Gillingham K, et al. Risk factors for chronic rejection in renal allograft recipients. Transplantation
. 1993; 55: 752–756; discussion 756–757.
6. Halloran PF, Melk A, Barth C. Rethinking chronic allograft nephropathy: the concept of accelerated senescence. J Am Soc Nephrol
. 1999; 10: 167–181.
7. Monaco AP, Burke JF Jr, Ferguson RM, et al. Current thinking on chronic renal allograft rejection: Issues, concerns, and recommendations from a 1997 roundtable discussion. Am J Kidney Dis
. 1999; 33: 150–160.
8. Pascual M, Theruvath T, Kawai T, et al. Strategies to improve long-term outcomes after renal transplantation. N Engl J Med
. 2002; 346: 580–590.
9. Kidney Disease: Improving Global Outcomes (KDIGO) Transplant Work Group. KDIGO clinical practice guideline for the care of kidney transplant recipients. Am J Transplant
. 2009; 9: S1–S155.
12. Roberts DM, Jiang SH, Chadban SJ. The Treatment of acute antibody-mediated rejection in kidney transplant recipients—a systematic review. Transplantation
. 2012; 94: 775–783.
13. Fehr T, Gaspert A. Antibody-mediated kidney allograft rejection: therapeutic options and their experimental rationale. Transpl Int
. 2012; 25: 623–632.
14. Barnett AN, Hadjianastassiou VG, Mamode N. Rituximab in renal transplantation. Transpl Int
. 2013; 26: 563–575.
15. Zarkhin V, Li L, Kambham N, et al. A randomized, prospective trial of rituximab for acute rejection in pediatric renal transplantation. Am J Transplant
. 2008; 8: 2607–2617.
16. Lehnhardt A, Mengel M, Pape L, et al. Nodular B-cell aggregates associated with treatment refractory renal transplant rejection resolved by rituximab. Am J Transplant
. 2006; 6: 847–851.
17. Moscoso-Solorzano GT, Baltar JM, Seco M, et al. Single dose of Rituximab plus plasmapheresis in an HIV patient with acute humoral kidney transplant rejection: a case report. Transplant Proc
. 2007; 39: 3460–3462.
18. Celik A, Saglam F, Cavdar C, et al. Successful therapy with rituximab of refractory acute humoral renal transplant rejection: a case report. Transplant Proc
. 2008; 40: 302–304.
19. Alausa M, Almagro U, Siddiqi N, et al. Refractory acute kidney transplant rejection with CD20 graft infiltrates and successful therapy with rituximab. Clin Transplant
. 2005; 19: 137–140.
20. Yang YW, Lin WC, Wu MS, et al. Early diagnosis and successful treatment of acute antibody-mediated rejection of a renal transplant. Exp Clin Transplant
. 2008; 6: 211–214.
21. Becker YT, Becker BN, Pirsch JD, et al. Rituximab as treatment for refractory kidney transplant rejection. Am J Transplant
. 2004; 4: 996–1001.
22. Vega J, Goecke H, Carrasco A, et al. Rituximab in the treatment of acute cellular rejection of renal allograft with CD20-positive clusters in the infiltrate. Clin Exp Nephrol
. 2011; 15: 308–311.
23. Tanriover B, Wright SE, Foster SV, et al. High-dose intravenous immunoglobulin and rituximab treatment for antibody-mediated rejection after kidney transplantation: a cost analysis. Transplant Proc
. 2008; 40: 3393–3396.
24. Faguer S, Kamar N, Guilbeaud-Frugier C, et al. Rituximab therapy for acute humoral rejection after kidney transplantation. Transplantation
. 2007; 83: 1277–1280.
25. Gomes AM, Pedroso S, Martins LS, et al. Diagnosis and treatment of acute humoral kidney allograft rejection. Transplant Proc
. 2009; 41: 855–858.
26. Mulley WR, Hudson FJ, Tait BD, et al. A single low-fixed dose of rituximab to salvage renal transplants from refractory antibody-mediated rejection. Transplantation
. 2009; 87: 286–289.
27. Rodríguez Ferrero M, Rincón A, Bucalo L, et al. Treatment of acute antibody-mediated rejection: a single-center experience. Transplant Proc
. 2010; 42: 2848–2850.
28. Kaposztas Z, Podder H, Mauiyyedi S, et al. Impact of rituximab therapy for treatment of acute humoral rejection. Clin Transplant
. 2009; 23: 63–73.
29. Lefaucheur C, Nochy D, Andrade J, et al. Comparison of combination plasmapheresis/IVIg/anti-CD20 versus high-dose IVIg in the treatment of antibody-mediated rejection. Am J Transplant
. 2009; 9: 1099–1107.
30. Levey AS, Bosch JP, Lewis JB, et al. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Intern Med
. 1999; 16( 130): 461–470.
31. Gill PS. A robust mixed linear model analysis for longitudinal data. Stat Med
. 2000; 19: 975–987.
32. Woodle ES, Gebel HM. Regulatory approval for new antihumoral therapies: addressing the barriers. Am J Transplant
. 2011; 11: 880–881.
33. Venetz JP, Pascual M. New treatments for acute humoral rejection of kidney allografts. Expert Opin Investig Drugs
. 2007; 16: 625–633.
34. Ramos EJ, Pollinger HS, Stegall MD, et al. The effect of desensitization protocols on human splenic B-cell populations in vivo. Am J Transplant
. 2007; 7: 402–407.
35. Kohei N, Hirai T, Omoto K, et al. Chronic antibody-mediated rejection is reduced by targeting B-cell immunity during an introductory period. Am J Transplant
. 2012; 12: 469–476.
36. Vo AA, Lukovsky M, Toyoda M, et al. Rituximab and intravenous immune globulin for desensitization during renal transplantation. N Engl J Med
. 2008; 359: 242–251.
37. Vo AA, Peng A, Toyoda M, et al. Use of intravenous immune globulin and rituximab for desensitization of highly HLA-sensitized patients awaiting kidney transplantation. Transplantation
. 2010; 89: 1095–1102.
38. Loupy A, Suberbielle-Boissel C, Zuber J, et al. Combined posttransplant prophylactic IVIg/anti-CD 20/plasmapheresis in kidney recipients with preformed donor-specific antibodies: a pilot study. Transplantation
. 2010; 89: 1403–1410.
39. Vo AA, Choi J, Cisneros K, et al. Benefits of rituximab combined with intravenous immunoglobulin for desensitization in kidney transplant recipients. Transplantation
. 2014; 15( 98): 312–319.
40. Vo AA, Sinha A, Haas M, et al. Factors predicting risk for antibody-mediated rejection and graft loss in highly human leukocyte antigen sensitized patients transplanted after desensitization. Transplantation
. 2015; 99: 1423–1430.
41. Zachary AA, Lucas DP, Montgomery RA, et al. Rituximab prevents an anamnestic response in patients with cryptic sensitization to HLA. Transplantation
. 2013; 95: 701–704.
42. Stegall MD, Chedid MF, Cornell LD. The role of complement in antibody-mediated rejection in kidney transplantation. Nat Rev Nephrol
. 2012; 8: 670–678.
43. Gaughan A, Wang J, Pelletier RP, et al. Key role for CD4 T cells during mixed antibody-mediated rejection of renal allografts. Am J Transplant
. 2014; 14: 284–294.
44. Colvin RB. Antibody-mediated renal allograft rejection: diagnosis and pathogenesis. J Am Soc Nephrol
. 2007; 18: 1046–1056.
45. Gloor J, Cosio F, Lager DJ, et al. The spectrum of antibody-mediated renal allograft injury: implications for treatment. Am J Transplant
. 2008; 8: 1367–1373.
46. Einecke G, Sis B, Reeve J, et al. Antibody-mediated microcirculation injury is the major cause of late kidney transplant failure. Am J Transplant
. 2009; 9: 2520–2531.
47. Kasi PM, Tawbi HA, Oddis CV, et al. Clinical review: serious adverse events associated with the use of rituximab—a critical care perspective. Crit Care
. 2012; 16: 231.
Supplemental Digital Content
Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.