Safety of Repeated Open-Label Treatment Courses of Intravenous Ofatumumab, a Human Anti-CD20 Monoclonal Antibody, in Rheumatoid Arthritis: Results from Three Clinical Trials

PLoS One. 2016 Jun 23;11(6):e0157961. doi: 10.1371/journal.pone.0157961. eCollection 2016.


Objectives: To investigate the safety of ofatumumab retreatment in rheumatoid arthritis.

Methods: Patients with active rheumatoid arthritis participating in two phase III trials (OFA110635 and OFA110634) and a phase II extension trial (OFA111752) received individualised open-label ofatumumab retreatment (700 mg X 2 intravenous infusions two weeks apart) ≥24 weeks following the first course and ≥16 weeks following further courses. Retreatment required evidence of clinical response followed by disease relapse. These studies were prematurely terminated by the sponsor to refocus development on subcutaneous delivery. Due to differences in study designs and populations, data are summarised separately for each study.

Results: 483 patients (243, 148 and 92 in OFA110635, OFA110634 and OFA111752 respectively) received up to 7 treatment courses of intravenous ofatumumab; cumulative duration of exposure was 463, 182 and 175 patient-years, respectively. Mean time between courses was 17-47 weeks. Ofatumumab induced a profound depletion of peripheral B-lymphocytes. Retreated patients derived benefit based on improvement in DAS28. Adverse events were reported for 93% (226/243), 91% (134/148) and 76% (70/92), serious adverse events for 18% (44/243), 20% (30/148) and 12% (11/92) and serious infections for 3% (8/243), 5% (7/148) and 1% (1/92) of patients in OFA110635, OFA110634 and OFA111752, respectively. The most common adverse events were infusion-related reactions during the first infusion of the first course (48-79%); serious infusion-related reactions were rare (<1% [1/243], 5% [8/148], and 1% [1/92] of patients). Two deaths occurred (fulminant hepatitis B virus infection and interstitial lung disease).

Conclusions: Ofatumumab was generally well tolerated with no evidence of increased safety risks with multiple retreatments. Serious infections were uncommon and did not increase over time.

Trial registration: 110635 110634 111752.

Publication types

  • Clinical Trial, Phase II
  • Clinical Trial, Phase III

MeSH terms

  • Administration, Intravenous
  • Antibodies, Monoclonal / administration & dosage*
  • Antibodies, Monoclonal / adverse effects*
  • Antibodies, Monoclonal, Humanized
  • Antirheumatic Agents / administration & dosage*
  • Antirheumatic Agents / adverse effects*
  • Arthritis, Rheumatoid / diagnosis
  • Arthritis, Rheumatoid / drug therapy*
  • Arthritis, Rheumatoid / immunology
  • Biomarkers
  • Female
  • Humans
  • Male
  • Pregnancy
  • Retreatment
  • Time-to-Treatment
  • Treatment Outcome


  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Antirheumatic Agents
  • Biomarkers
  • ofatumumab

Grant support

The work was funded by GlaxoSmithKline Pharmaceuticals and Genmab. The Sponsor(s) were involved in the study design, data collection and analysis. GlaxoSmithKline also provided support in the form of salaries and shares for authors EQ MC SM HP and RK. The decision to publish and the preparation of the manuscript were undertaken by the named authors.