Cancer risk with tocilizumab/sarilumab, abatacept, and rituximab treatment in patients with rheumatoid arthritis: a Danish cohort study

Objectives: To investigate cancer risk in rheumatoid arthritis (RA) patients treated with tocilizumab/sarilumab, abatacept, or rituximab compared with those who received tumour necrosis factor inhibitors (TNFi) and compared with biological disease-modifying anti-rheumatic drugs (bDMARD) naïve RA patients.

Methods: Nationwide registry-based cohort study of RA patients initiating treatment with tocilizumab/sarilumab, abatacept, rituximab, TNFi, and bDMARD-naive patients their second type of conventional synthetic DMARD (csDMARD). Patients were identified in DANBIO and followed for cancer from 2006-2020. Patients could contribute multiple treatments, with person years (PYRS), deaths, and cancers allocated to each treatment group in a 'latest type of treatment' manner. Inverse probability of treatment weighting and weighted cause-specific Cox models were used to calculate hazard ratios (HRs) for cancer in each tocilizumab/sarilumab, abatacept, and rituximab group compared with TNFI and bDMARD naïve groups, respectively.

Results: In total, 21 982 treatment initiations, 96 475 PYRS, and 1423 cancers were identified. There were no statistically significant increased HRs for overall cancer in tocilizumab/sarilumab, abatacept, or rituximab treatment groups (HRs ranged from 0.7-1.1). More than five years of abatacept exposure showed a non-significantly increased HR compared with TNFi (HR 1.41, 95% confidence intervals CI 0.74-2.71). For hematological cancers, rituximab treatment showed non-significantly reduced HRs: vs TNFi (HR 0.09; 95%CI 0.00-2.06) and bDMARD-naïve (HR 0.13; 95%CI 0.00-1.89).

Conclusion: Treatment with tocilizumab/sarilumab, abatacept, or rituximab in RA patients was not associated with increased risks of cancer compared with TNFi-treated and with bDMARD-naïve RA patients in a real-world setting.