Background: Concerns have been raised about a potential link between the use of TNF inhibitors and development of malignancy in the pediatric population. We examined the worldwide experience of etanercept use in pediatric patients and the occurrence of malignancies as reported from clinical trials, registry studies, post-marketing surveillance, and published scientific literature.
Methods: All reports of "malignancy" in pediatric patients (including subjects who received etanercept before age 18 and developed a malignancy before age 22) were collected from the etanercept clinical trials database and global safety database using the Medical Dictionary for Regulatory Activities (MedDRA; v12.0) standardized MedDRA query "Malignancies" from 1998 to August 2009. Cases were collected irrespective of treatment indication. All cases were included regardless of exposure to other TNF blockers or other biologics and whether the other exposure was before or after etanercept.
Results: A total of 18 potential malignancies were identified: 4 leukemias, 7 lymphomas, and 7 solid tumors. Three of the 18 malignancies remain unconfirmed. No malignancies were reported from clinical trials or the open-label extension studies in any indication in children.
Conclusion: The data suggest that there does not appear to be an increased risk of malignancy overall with the use of etanercept. Among etanercept-exposed patients aged 4 to 17 years, the estimated worldwide and US reporting rates for lymphoma were approximately 0.01 per 100 patient-years (1 in 10,000 pt-yrs). While the reported rate of lymphoma is higher in pediatric patients treated with etanercept than in normal children, the expected rate of lymphoma in biologic naïve JIA patients is currently unknown. The risk of TNF inhibitors in the development of malignancies in children and adolescents is difficult to assess because of the rarity of malignant events, the absence of knowledge of underlying frequency of leukemia and lymphoma in JIA, and the confounding use of concomitant immunosuppressive medications.