title: Effectiveness of two different doses of rituximab for the treatment of rheumatoid arthritis in an international cohort: data from the CERERRA collaboration.
abstract: BACKGROUND
  The approved dose of rituximab (RTX) in rheumatoid arthritis is 1000 mg × 2, but some data have suggested similar clinical efficacy with 500 mg × 2. The purpose of this study was to compare the effectiveness of the regular and low doses given as first treatment course.
  
  
  METHODS
  Twelve European registries participating in the CERERRA collaboration (The European Collaborative Registries for the Evaluation of Rituximab in Rheumatoid Arthritis) submitted anonymized datasets with demographic, efficacy and treatment data for patients who had started RTX. Treatment effectiveness was assessed by DAS28 reductions and EULAR responses after 6 months.
  
  
  RESULTS
  Data on RTX dose were available for 2,873 patients, of whom 2,625 (91.4 %) and 248 (8.6 %) received 1000 mg × 2 and 500 mg × 2, respectively. Patients treated with 500 mg × 2 were significantly older, had longer disease duration, higher number of prior DMARDs, but lower number of prior biologics and lower baseline DAS28 than those treated with 1000 mg × 2. Fewer patients in the low-dose group received concomitant DMARDs but more frequently received concomitant corticosteroids. Both doses led to significant clinical improvements at 6 months. DAS28 reductions at 6 months were comparable in the 2 dose regimens [mean DeltaDAS28 ± SD -2.0 ± 1.3 (high dose) vs. -1.7 ± 1.4 (low dose), p = 0.23 adjusted for baseline differences]. Similar percentages of patients achieved EULAR good response in the two dose groups, 18.4 % vs. 17.3 %, respectively (p = 0.36).
  
  
  CONCLUSIONS
  In this large observational cohort initial treatment with RTX at 500 mg × 2 and 1000 mg × 2 led to comparable clinical outcomes at 6 months.
authors.affiliation: Department of Medicine, Karolinska Institute, Unit for Clinical Research Therapy, Inflammatory Diseases (ClinTrid), D1:00, Karolinska Universitetssjukhustet, 171 76, Stockholm, Sweden. Aikaterini.chatzidionysiou@karolinska.se.
authors.forename: Katerina
authors.initials: K
authors.lastname: Chatzidionysiou
authors.affiliation: Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway. Elisabeth_lie@yahoo.no.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lie
authors.affiliation: ARBITER, Institute of Rheumatology, Moscow, Russia. nasonov@irramn.ru.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Nasonov
authors.affiliation: ARBITER, Institute of Rheumatology, Moscow, Russia. gvl3@yandex.ru.
authors.forename: Galina
authors.initials: G
authors.lastname: Lukina
authors.affiliation: DANBIO, Department of Rheumatology, Copenhagen University Hospital at Glostrup, Copenhagen, Denmark. merete.hetland@dadlnet.dk.
authors.forename: Merete Lund
authors.initials: ML
authors.lastname: Hetland
authors.affiliation: Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark. ulrik.tarp@ki.au.dk.
authors.forename: Ulrik
authors.initials: U
authors.lastname: Tarp
authors.affiliation: Cantacuzino Hospital, Bucharest, Romania. iancuta@hotmail.com.
authors.forename: Ioan
authors.initials: I
authors.lastname: Ancuta
authors.affiliation: Charles University, Prague, Czech Republic. pavelka@revma.cz.
authors.forename: Karel
authors.initials: K
authors.lastname: Pavelka
authors.affiliation: ROB-FIN Helsinki University Central Hospital, Helsinki, Finland. dan.nordstrom@hus.fi.
authors.forename: Dan C
authors.initials: DC
authors.lastname: Nordström
authors.affiliation: SCQM registry, University Hospital of Geneva, Geneva, Switzerland. Cem.Gabay@hcuge.ch.
authors.forename: Cem
authors.initials: C
authors.lastname: Gabay
authors.affiliation: Rheumatology Research Unit, Instituto de Medicina Molecular, Lisbon, Portugal. helenacanhao@gmail.com.
authors.forename: Helene
authors.initials: H
authors.lastname: Canhão
authors.affiliation: University Medical Center, Ljubljana, Slovenia. matija.tomsic@kclj.si.
authors.forename: Matija
authors.initials: M
authors.lastname: Tomsic
authors.affiliation: Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands. p.vanriel@reuma.umcn.nl.
authors.forename: Piet L C M
authors.initials: PL
authors.lastname: van Riel
authors.affiliation: Hospital Clinico Universitet De Santiago, Santiago, Spain. Juan.Jesus.Gomez-Reino.Carnota@sergas.es.
authors.forename: Juan
authors.initials: J
authors.lastname: Gomez-Reino
authors.affiliation: Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway. t.k.kvien@medisin.uio.no.
authors.forename: Tore K
authors.initials: TK
authors.lastname: Kvien
authors.affiliation: Department of Medicine, Karolinska Institute, Unit for Clinical Research Therapy, Inflammatory Diseases (ClinTrid), D1:00, Karolinska Universitetssjukhustet, 171 76, Stockholm, Sweden. ronald.van.vollenhoven@ki.se.
authors.forename: Ronald F
authors.initials: RF
authors.lastname: van Vollenhoven
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000008:administration & dosage*; D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D015331:Cohort Studies; D003299:Cooperative Behavior; D016208:Databases, Factual; D004305:Dose-Response Relationship, Drug; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D038622:Internationality; D008297:Male; D008875:Middle Aged; D012042:Registries; D000069283:Rituximab / Q000008:administration & dosage*; D013223:Statistics as Topic / Q000379:methods; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D000069283:Rituximab