Objective: To evaluate whether patients with rheumatoid arthritis who did not respond sufficiently to tocilizumab (TCZ) plus disease-modifying antirheumatic drug (DMARD) treatment by Week 8 responded at later timepoints when continuing to take their original dose of TCZ.
Methods: In this posthoc analysis of data from phase III randomized controlled trials of inadequate responders (IR) to DMARD or tumor necrosis factor-α inhibitors (anti-TNF), percentages of patients meeting early response criteria were calculated by randomized treatment arm (TCZ 4 mg/kg, 8 mg/kg, or placebo in combination with DMARD). Percentages of patients achieving certain disease activity thresholds at later timepoints were calculated for patients who had/had not achieved response by Week 8.
Results: In DMARD-IR early nonresponders, 29.0%, 17.2%, and 3.7% of TCZ 8 mg/kg-randomized, TCZ 4 mg/kg-randomized, and placebo-randomized patients, respectively, achieved 28-joint Disease Activity Score (DAS28) ≤ 3.2 by Week 24. Among anti-TNF-IR patients without early response, 26.5%, 8.5%, and 1.9% of TCZ 8 mg/kg-randomized, TCZ 4 mg/kg-randomized, and placebo-randomized patients, respectively, achieved DAS28 ≤ 3.2 at Week 24.
Conclusion: A substantial number of DMARD-IR patients taking TCZ 4 or 8 mg/kg and anti-TNF-IR patients taking TCZ 8 mg/kg who failed to respond by 8 weeks benefited from continued TCZ treatment in combination with DMARD. In contrast, the anti-TNF-IR patients without early responses who continued to take TCZ 4 mg/kg were unlikely to experience a cumulative benefit. ClinicalTrials.gov registration numbers: NCT00106548, NCT00106574, NCT00106535, NCT00106522.
Keywords: ANTIRHEUMATIC AGENTS; MONOCLONAL ANTIBODIES; RHEUMATOID ARTHRITIS; TREATMENT OUTCOME.