NEW YORK (Reuters Health)—A large Swedish study1 provides reassuring data on the risk of cancer in patients with rheumatoid arthritis (RA) treated with tumor necrosis factor (TNF) inhibitors or with tocilizumab, abatacept or rituximab.
Overall, the risk of malignant neoplasms did not differ between patients treated with a first anti-TNF drug; a second anti-TNF drug; tocilizumab, abatacept, rituximab; or conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs), with the possible exception of an increased risk of squamous cell skin cancer in patients treated with abatacept, the study team reported online September 18 in JAMA Internal Medicine.
“Considering the widespread and increasing use of biological disease-modifying anti-rheumatic drugs (bDMARDs) to treat chronic inflammatory conditions, and the concern that immunomodulation may alter cancer risk and progression, the limited available data on use of these therapies as used in clinical practice and cancer risks are a concern,” Dr. Hjalmar Wadstrom from the Karolinska Institutet in Stockholm and the Anti-Rheumatic Therapy in Sweden (ARTIS) study group, note in their paper.
Using registry data, they identified cohorts of RA patients starting treatment with tocilizumab, abatacept, or rituximab; those using a TNF inhibitor as a first-ever or second-ever bDMARD; a biologics-naive cohort treated with csDMARDs; and a general population comparator cohort.
The dataset totaled 15,129 initiations of a TNF inhibitor as the first or second bDMARD, 7,405 initiations of other bDMARDs, and 46,610 csDMARD users, as well as 107,491 adults in the general population.
Across the cohorts, the mean age varied from 58 to 64, and the proportion of women varied from 71% to 80%.
“In this study, to our knowledge one of the largest observational studies on the risk of malignant neoplasms in RA patients treated with bDMARDs to date, we found that the overall risk of developing cancer among patients with RA initiating treatment with TNF inhibitors or non-TNF inhibitors, as used in clinical practice, did not differ from that of patients with bDMARD-naive RA,” Dr. Wadstrom and colleagues report.
“We found no increased risk of malignant neoplasms overall, with 95% CIs (confidence intervals) excluding clinically meaningfully increased risks. In addition, we found no increase in risk among patients starting TNF inhibitor as second bDMARD,” they say.
There were no “signals” of increased risks for any specific cancer types, with the exception of abatacept, with the data suggesting an increased risk of squamous cell skin cancer (adjusted hazard ratio, 2.15), although the researchers caution that this observation needs to be replicated.
A limitation of the study is that follow-up time and statistical power are “inherently limited to less than 10 years,” given the relatively recent introduction of non-TNF inhibitor therapy in RA.
Despite this, they say it can be concluded from this study that “short-to medium-term use of tocilizumab, abatacept, rituximab, or anti-TNF drugs seems to be safe with regard to risks of incident cancer.”
- Wadström H, Frisell T, Askling J, et al. Malignant Neoplasms in Patients With Rheumatoid Arthritis Treated With Tumor Necrosis Factor Inhibitors, Tocilizumab, Abatacept, or Rituximab in Clinical Practice: A Nationwide Cohort Study From Sweden. JAMA Intern Med. 2017 Sept 18. [Epub ahead of print]