Association Between Malignancy and Topical Use of Pimecrolimus

IMPORTANCE A black box warning describes a potential risk of malignancy associated with topical use of pimecrolimus to treat atopic dermatitis due to its similarity to oral calcineurin inhibitors used in solid-organ transplantation and spontaneous reporting of malignancies, including lymphomas and cutaneous malignancies. OBJECTIVE To evaluate the risk of malignancy in a postmarketing study of children exposed to pimecrolimus. DESIGN, SETTING, AND PARTICIPANTS A longitudinal cohort study among a nationwide ongoing long-term cohort of children enrolled in the Pediatric Eczema Elective Registry (PEER) who had a history of atopic dermatitis and pimecrolimus use with data available up through May 2014. MAIN OUTCOMES AND MEASURES Reports of malignancy among those in the PEER compared with expected rates from the Surveillance, Epidemiology, and End Results (SEER) program. RESULTS Overall, 7457 children were enrolled in the PEER, for a total of 26 792 person-years. Children used a mean (SD) of 793 (1356) g of pimecrolimus when enrolled in the study. As of May 2014, five malignancies had been reported. These include 2 leukemias, 1 osteosarcoma, and 2 lymphomas. No skin cancers were reported. The standardized incidence ratio for all malignancies (primary outcome) based on the age-standardized SEER population was 1.2 (95% CI, 0.5-2.8). As secondary analyses, the standardized incidence ratios (based on 2 cases for each) were 2.9 (95% CI, 0.7-11.7) for lymphoma and 2.0 (95% CI, 0.5-8.2) for leukemia. None of these findings were statistically significant. CONCLUSIONS AND RELEVANCE Based on more than 25 000 person-years of follow-up, it seems unlikely that topical pimecrolimus as it was used in the PEER cohort to treat atopic dermatitis is associated with an increased risk of malignancy.