Editor, – Since the article on tumour necrosis factor inhibitors was published (Aust Prescr 2006;29:67-70), further evidence has emerged about the risk of malignancy associated with these drugs. A meta-analysis of nine published randomised placebo-controlled clinical trials of adalimumab and infliximab in rheumatoid arthritis showed a 3.3-fold (95% CI* 1.2-9.1) increased risk of malignancy.1Patients with prior malignancy were excluded from these trials. Malignancies were significantly more common in those taking high doses compared to low doses of tumour necrosis factor inhibitors.
A US observational study of 6597 patients with rheumatoid arthritis treated with tumour necrosis factor inhibitors showed that their use was associated with an increased risk of non-melanotic skin cancer (odds ratio 1.5, 95% CI 1.2-1.8) and melanoma (odds ratio 2.3, 95% CI 0.9-5.4).2However, no other malignancy was associated and the overall risk of any cancer was 1.0 (95% CI 0.8-1.2).
There is no current evidence for the safety of tumour necrosis factor inhibitors in patients with a history of malignancy. Hence, both the UK guidelines and the current product information for these products recommend that tumour necrosis factor inhibitors should be used with caution in patients with previous malignancy.3We suggest that until more long-term safety data are available, patients with recent malignancy should not be required to 'fail' a tumour necrosis factor inhibitor before being eligible for an alternative biological disease-modifying antirheumatic drug therapy under the Pharmaceutical Benefits Scheme.
* CI = confidence interval
Catherine L Hill
Staff Specialist, Rheumatology Unit
The Queen Elizabeth Hospital
Adelaide
Peter Nash
Director, Rheumatology Research Unit
Sunshine Coast
Associate Professor
Department of Medicine
University of Queensland