Rituximab as maintenance therapy for ANCA-associated vasculitides: pooled analysis and long-term outcome of 277 patients included in the MAINRITSAN trials.

Objective: To compare the long-term efficacy and safety of azathioprine (AZA), 18-month fixed-schedule rituximab (RTX), 18-month tailored RTX and 36-month RTX in preventing relapses in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis who achieved a complete remission after induction therapy. Patients treated with 36-month RTX received either a fixed or a tailored regimen for the first 18 months and a fixed regimen for the last 18 months (36-month fixed/fixed RTX and 36-month tailored/fixed RTX, respectively).
Methods: The Maintenance of Remission using Rituximab in Systemic ANCA-associated Vasculitis (MAINRITSAN) trials sequentially compared: 18-month fixed-schedule RTX versus AZA (MAINRITSAN); 18-month fixed-schedule RTX versus 18-month tailored-RTX (MAINRITSAN2); and extended therapy to 36 months with four additional RTX infusions after MAINRITSAN2 versus placebo (MAINRITSAN3). Patients were then followed prospectively through month 84 and their data were pooled to analyse relapses and adverse events. The primary endpoint was relapse-free survival at month 84.
Results: 277 patients were enrolled and divided in 5 groups: AZA (n=58), 18-month fixed-schedule RTX (n=97), 18-month tailored-RTX (n=40), 36-month tailored/fixed RTX (n=42), 36-month fixed/fixed RTX (n=41). After adjustment for prognostic factors, 18-month fixed-schedule RTX was superior to AZA in preventing major relapses at month 84 (HR 0.38, 95% CI 0.20 to 0.71). The 18-month tailored-RTX regimen was associated with an increased risk of major relapse compared with fixed-schedule regimen (HR 2.92, 95% CI 1.43 to 5.96). The risk of major relapse was similar between 36-month fixed/fixed and 18-month fixed-RTX (HR 0.69, 95% CI 0.38 to 1.25).
Conclusions: According to these results, it appears that the 84-month remission rate is higher with an 18-month fixed RTX regimen compared with AZA and 18-month tailored RTX. Also, extending RTX to 36 months does not appear to reduce the long-term relapse rate compared with the 18-month fixed RTX regimen. However, as this study was underpowered to make this comparison, further prospective studies are needed to determine the potential long-term benefits of extending treatment in these patients.
Competing Interests: Competing interests: All authors have completed the Unified Competing Interest form (available on request from the corresponding author) and declare compting interest as follows: Dr BT reports receiving consulting and speaking fees (Roche, LFB, Grifols, GSK). Dr XP reports receiving speaking fees and honoraria (Pfizer, LFB, Roche) and a research grant (Pfizer). Dr. LG reports receiving fees for serving on an advisory board from GlaxoSmithKline and lecture fees from Roche, Actelion, Pfizer, CSL Behring, LFB Pharma, and Octapharma. Dr. CP reports receiving fees for serving on advisory boards from Roche, Genzyme, and GlaxoSmithKline, lecture fees from Roche, Bristol-Myers Squibb, and EuroImmune, and grant support from Roche. Dr. AK reports receiving lecture fees from Roche and travel support from Roche and Amgen. Dr. FM reports receiving personal fees from Actelion and travel support from Sobi and LFB Pharma. Dr. PG reports receiving personal fees from Gambro and LEO Pharma. Dr. TQ reports receiving travel support from Merck Sharp & Dohme, Alexion, and Actelion. Dr. Blanchard-Delaunay reports receiving personal fees from CSL Behring. Dr. PG reports receiving travel support from Octapharma, LFB Pharma, Roche, and Novartis. Dr. P-LC reports receiving travel support from Gambro, Bellco, Roche, Hemotech, and Sanofi. Dr. NL reports receiving travel support from GlaxoSmithKline. Dr. Hamidou reports receiving lecture fees from Roche and LFB Pharma, personal fees from Actelion, and travel support from Roche, Actelion, LFB Pharma, and GlaxoSmithKline. Dr. MD reports receiving personal fees from Fresenius Medical Care. Dr. ED reports receiving lecture fees and travel support from Shire, Amgen, and Genzyme, and grant support from Roche. Dr. BB reports receiving grant support from Roche/Chugai. No other potential conflict of interest relevant to this article was reported.
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