The risk of non-Hodgkin's lymphoma (NHL) with tumor necrosis factor alpha (TNF-α) inhibitors is unclear, whether related to concomitant thiopurines usage or due to the underlying inflammatory disease. We sought to review all cases of T-cell NHL reported to the Food and Drug Administration (FDA) in patients receiving TNF-α inhibitors for all approved indications and examine the risk of T-cell NHL with TNF-α inhibitors in comparison with the use of thiopurines in inflammatory bowel disease (IBD).
The FDA Adverse Event Reporting System (AERS) was queried for all lymphomas following treatment with the following TNF-α inhibitors: infliximab, adalimumab, certolizumab, etanercept, and their trade names. Full reports for T-cell NHL cases were identified using the Freedom of Information Act. In addition, T-cell NHL reported in patients IBD with the use of the thiopurines-azathioprine, 6-mercaptopurine, and their trade names were also collected. A search of MEDLINE was performed for additional T-cell NHL with TNF-α inhibitors or thiopurines, not reported to the FDA but available in published literature. The histological subtypes of T-cell NHL reported with TNF-α inhibitors were compared with reported subtypes in Surveillance Epidemiology and End Results (SEER) -17 registry. Reported risk of T-cell NHL in IBD with TNF-α inhibitors, thiopurines, or concomitant use was calculated using Fisher's exact test using 5-aminosalicylates as control drugs.
A total of 3,130,267 reports were downloaded from the FDA AERS (2003-2010). Ninety-one cases of T-cell NHL with TNF-α inhibitors were identified in the FDA AERS and nine additional cases were identified on MEDLINE search. A total of 38 patients had rheumatoid arthritis, 36 cases had Crohn's disease, 11 had psoriasis, 9 had ulcerative colitis, and 6 had ankylosing spondylitis. Sixty-eight of the cases (68%) involved exposure to both a TNF-α inhibitor and an immunomodulator (azathioprine, 6-mercaptopurine, methotrexate, leflunomide, or cyclosporine). Hepatosplenic T-cell lymphoma (HSTCL) was the most common reported subtype, whereas mycosis fungoides/Sezary syndrome and HSTCL were identified as more common with TNF-α-inhibitor exposure compared with SEER-17 registry. Nineteen cases of T-cell NHL with thiopurines were identified in the FDA AERS and one additional case on MEDLINE. Reported risk of T-cell NHL was higher with TNF-α inhibitor use in combination with thiopurines (95% confidence interval (CI) 4.98-354.09; P<0.0001) and thiopurines alone (95% CI 8.32-945.38; P<0.0001) but not with TNF-α inhibitor use alone (95% CI 0.13-10.61; P=1.00).
Risk of T-cell NHL is increased with TNF-α inhibitor use in combination with thiopurines but not with TNF-α inhibitors alone.