Clinical efficacy of cabozantinib in two pediatric patients with recurrent renal cell carcinoma.

Advanced-stage renal cell carcinoma (RCC) carries a dismal prognosis for pediatric patients with few studied therapeutic options. Cabozantinib is a small molecule tyrosine kinase inhibitor against the oncoprotein MET. It is currently approved by the U.S. Food and Drug administration for second-line treatment of RCC in adults. There is no published data on its use in children with RCC. We report here two pediatric patients with recurrent metastatic RCC whose tumors expressed MET and were treated with cabozantinib. Both patients had significant disease regression and symptomatic improvement for over 15 months with tolerable adverse effects. Cabozantinib can maintain prolonged disease control in pediatric RCC and warrants further study.