Cancer risk associated with abatacept among older individuals with rheumatoid arthritis in the United States.

Objective: To examine the association between abatacept therapy and cancer risk among individuals with rheumatoid arthritis (RA).

Methods: We conducted a case-control study of individuals with RA in the United States aged 65 to 99 years (17,665 cancer cases and 53,652 controls during 2008 to 2019) using the SEER-Medicare database. For assessing risk of nonmelanoma skin cancer (NMSC), individuals of White race with RA and NMSC and corresponding controls were selected from Medicare beneficiaries residing in SEER areas. Exposure to abatacept, tumor necrosis factor inhibitors (TNFis), and conventional disease-modifying antirheumatic drugs (cDMARDs) was ascertained using prescription claims. Individuals exposed to both abatacept and TNFi were excluded. We calculated adjusted odds ratios (ORs) to measure associations between abatacept (±cDMARD) and risk for cancer overall, 17 specific cancer sites, and NMSC.

Results: 2.5% of SEER cancer cases and 2.6% of controls were treated with abatacept (±cDMARD). Overall cancer risk was not associated with exposure to abatacept compared with TNFi (±cDMARD) (adjusted OR 1.03, 95% confidence interval [95%CI] 0.88-1.21) or with cDMARDs only (1.02, 0.87-1.19). Abatacept was associated with increased NMSC risk compared to both TNFi (±cDMARD) (adjusted OR 1.31, 95%CI 1.01-1.70) and cDMARDs only (1.31, 1.01-1.71). Abatacept was also associated with increased lung cancer risk among individuals with recent-onset RA (adjusted OR 1.53, 95%CI 1.01 to 2.32, compared with TNFi). These associations were not significant after correction for multiple comparisons.

Conclusions: Among older adults with RA, abatacept exposure was not associated with cancer risk overall, but there was some evidence for increased risks of NMSC and lung cancer.