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

We sought to examine the association between abatacept therapy and cancer risk among individuals with rheumatoid arthritis (RA).

We conducted a case-control study of individuals with RA in the United States aged 65-99 years (17 665 patients with cancer and 53 652 control individuals during 2008-2019) using the Surveillance, Epidemiology, and End Results (SEER) Program-Medicare database. For assessing risk of nonmelanoma skin cancer, individuals of White race with RA and nonmelanoma skin cancer and corresponding control individuals were selected from among Medicare beneficiaries residing in SEER areas. Exposure to abatacept, tumor necrosis factor (TNF) inhibitors, and conventional disease-modifying antirheumatic drugs (DMARDs) was ascertained using prescription claims. Individuals exposed to both abatacept and TNF inhibitors were excluded. We calculated adjusted odds ratios (AORs) to measure associations between abatacept (with or without a conventional DMARD) and overall risk of cancer, 17 specific cancer sites, and nonmelanoma skin cancer.

Overall, 2.5% of SEER cancer cases and 2.6% of control individuals were treated with abatacept (with or without a conventional DMARD). Overall cancer risk was not associated with exposure to abatacept compared with a TNF inhibitor (with or without a conventional DMARD) (AOR = 1.03, 95% confidence interval [CI] = 0.88 to 1.21) or with conventional DMARDs only (AOR = 1.02, 95% CI = 0.87 to 1.19). Abatacept was associated with increased nonmelanoma skin cancer risk compared with both TNF inhibitors (with or without a conventional DMARD) (AOR = 1.31, 95% CI = 1.01 to 1.70) and conventional DMARDs only (AOR = 1.31, 95% CI = 1.01 to 1.71). Abatacept was also associated with increased lung cancer risk among individuals with recent-onset RA (AOR = 1.53, 95% CI = 1.01 to 2.32, compared with TNF inhibitors). These associations were not statistically significant after correction for multiple comparisons.

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