Pediatric Use of TNF inhbitors Does Not Increase Malignancy Risk Save

A study of USA administrative claims data between 2000 to 2014 assessed the risk of cancer with exposure to tumour necrosis factor inhibitor (TNFi) in pediatric patients and found that TNFi therapy did not significantly increase the risk compared those not receiving TNFi.

While it is well known that TNFi do not confer any higher or additional risk of neoplasia in adults treated for rheumatoid arthritis and other inflammatory conditions, the issue is less clear in children. Current product labeling states "..lymphoma and other malignancies, some fatal, have been reported in children and adolescent patients treated with TNF blockers..", based on the best available data (albeit limited) from registries and spontaneous postmarketing reports. 

What has been lacking is clear understanding of the background cancer risk in polyarticular JIA along with well-designed trials to examine if there is an additional risk imposed by the biologic drug.

This retrospective cohort study examined pediatric patients with juvenile idiopathic arthritis (JIA), pediatric inflammatory bowel disease (pIBD) and pediatric plaque psoriasis (pPsO), exposed to their first TNFi. Standardised incidence ratios (SIRs) comparing the observed number of malignancies to the expected numbers according to cancer surveillance data.  

Among 15,598 children treated with TNFi and 73 839 children without TNFi exposure, they found 15 malignancies among children with TNFi use (SIR 2.9 (1.6 to 4.9)) and 42 malignancies among children without TNFi use (SIR 2.1 (1.5 to 2.9)).

The adjusted hazard ratio (aHR) was 1.58 (0.88 to 2.85) for TNFi use versus no TNFi use.

In pIBD, thiopurine plus TNFi use was associated with a higher SIR (aHR 6.0 (1.2 to 17.5)) compared with TNFi use without thiopurine use (2.5 (0.7 to 6.4)).

Children diagnosed with JIA, pIBD and pPsO had an increased rate of malignancy compared with the general population.

However, TNFi did not appear to significantly further increase the risk compared with no TNFi use.