One of the central research questions of RABBIT is whether biologic DMARDs, which block TNF-a or other messengers to treat rheumatic diseases, increase the long-term risk of cancer in RA patients. We investigated 5,120 RA patients observed in RABBIT over a mean duration of two years. Treatment with biologic DMARDs was not associated with a higher risk to develop cancer than treatment with non-biologic DMARDs.
We further examined the respective risk in patients with a history of malignant diseases prior to the start with a biologic DMARD. There was no evidence of a higher risk of developing cancer in patients with a cancer history treated with TNF-a inhibitors or anakinra compared to the risk in respective patients treated with non-biologic DMARDs. Since there were only a small number of patients with cancer history (n=122), these results have to be confirmed in a larger cohort (Strangfeld et al. Arthritis Res Ther. 2010; 12: R5).