Background The data on how to optimally retreat patients with RA with rituximab (RTX) have been limited so far.
Objectives The aim of this analysis was to compare two common retreatment strategies: A fixed retreatment approach and retreatment when a flare occurs.
Methods Pooled data from the Collaborating European Registries for Rituximab in RA (CERERRA) project were used. We identified RA patients who had received at least 2 retreatments (3 courses) with RTX and who had available information about the strategy for retreatment (according to the physician's opinion). The two retreatment strategies were compared by applying an adjusted mixed model analysis with DAS28 improvement as the dependent variable.
Results A total of 800 patients were retreated at least twice: 616 patients retreated because of a flare (442 at 1st and 174 at 2nd retreatment) and 184 receiving fixed retreatment (128 at 1st and 56 at 2nd retreatment). Baseline characteristics (incl. age, sex, seropositivity, disease duration, number of prior DMARDs and biologics) at first course of RTX did not differ significantly between the two groups. However, patients retreated on flare had, as expected, a significantly higher DAS28-ESR at the time of 1st retreatment (5.1±1.3 vs. 4.1±1.4, p<0.0001), and a higher HAQ (1.5±0.7 vs. 1.3±0.8, p=0.001). They had also a slightly higher baseline (at the time of RTX start) DAS28 (6.3±1.0 vs. 6.1±1.2, p=0.03). Those retreated on flare were more likely to be treated with corticosteroids (58% vs. 46%, p=0.01) but less likely to receive concomitant DMARDs (82% vs. 92%, p=0.005).
The baseline (=start of each cycle) deltaDAS28 (compared to the DAS28 at the time of RTX start) for the two groups is shown in figure 1. Patients receiving fixed retreatment had a significantly higher (in absolute number) deltaDAS28 (p<0.0001) at the start of each cycle, compared to those retreated on-flare. In the adjusted mixed model analysis, we compared the two retreatment groups for the 1st and the 2nd retreatment separately using estimated marginal means. For the 1st retreatment a fixed retreatment yielded significantly better results than the “on-flare”: mean deltaDAS28=-2.4 (95% CI: -3.0; -1.7) vs. -1.8 (95% CI: -3.6; -0.03), p<0.0001. Similar results were found for the 2nd retreatment: mean deltaDAS28=-2.6 (95% CI: -3.1; -2.2) vs. -1.6 (95% CI: -1.8; -1.4), p<0.0001.
Conclusions A fixed RTX retreatment strategy in RA seems to be more effective than the retreatment “on-flare” strategy.
Disclosure of Interest K. Chatzidionysiou: None declared, E. Lie: None declared, E. Nasonov: None declared, G. Lukina: None declared, M. Hetland: None declared, U. Tarp: None declared, K. Pavelka: None declared, C. Gabay: None declared, D. Nordström: None declared, H. Canhão: None declared, M. Tomsic: None declared, P. van Riel: None declared, J. Gomez-Reino: None declared, I. Ancuta: None declared, T. Kvien Grant/research support: research funding to the Diakonhjemmet Hospital from AbbVie, BMS, MSD/Schering-Plough, Pfizer/Wyeth, Roche and UCB, Consultant for: AbbVie, BMS, Celltrion, Eli Lilly, Hospira, MSD/Schering-Plough, Orion Pharma, Pfizer/Wyeth, Roche, UCB, R. van Vollenhoven: None declared