The incidence and characterization of weight gain associated with MEK inhibitors in pediatric patients

Abstract

Mitogen-activated protein kinase enzyme (MEK) inhibitors are used in the treatment of pediatric patients with neurofibromatosis, low grade glioma, and astrocytoma, and may demonstrate a unique side effect profile in this population. Inhibition of MEK has been shown to decrease interleukin (IL)-6 production, a proinflammatory cytokine. The inhibition of IL-6 and other proinflammatory cytokines is thought to decrease muscle wasting and may contribute to weight gain. However, there is limited information on the association of MEK inhibition and weight gain in children and adolescents. This study aimed to characterize and define the incidence of significant weight gain associated with MEK inhibitors in pediatric patients. This was a retrospective chart review conducted at a tertiary pediatric hospital. Children 1-18.99 years old were included if they started a MEK inhibitor from July 1, 2013-October 31, 2021, and continued therapy for at least 6 months. Significant weight gain was defined as ≥5% increase in patient's weight-for-age percentile. Sixty-seven patients were included in the analysis. Sixty-two received trametinib and 5 received selumetinib. An increase in weight-for-age percentile ≥5% was seen in 60% of patients receiving selumetinib and 56% on trametinib. The Dunnett's multiple comparisons test revealed a difference in weight-for-age percentile from baseline to end of data collection (p=.0173). Patients who were obese at baseline were more likely to lose weight during treatment, while underweight patients increased in weight-for-age percentiles. Weight gain may be a notable side effect associated with the use of MEK inhibitors in pediatric patients.