Sirolimus for the treatment of vascular anomalies in children

Abstract

Vascular anomalies (VA) comprise a heterogeneous group of diseases associated with congenital angiogenesis disorder. There are no currently developed unified protocols and treatment regimens for systemic forms of VA. Numerous advantages show sirolimus, an mTOR inhibitor, as a well tolerated and effective antiproliferative and antiangiogenic therapy in patients with VA. The article presents the results of treatment of 211 patients with VA (6 patients with vascular tumors and 205 patients with vascular malformations) aged 2 months to 17 years (median – 9 years), who received sirolimus therapy for 1–86 months (median – 24 months). Sirolimus was administered at a starting dose of 0.8 mg/m2/day orally in two doses with an interval of 12 hours. The concentration of the blood preparation was maintained in the therapeutic range of 6–15 ng/ml. Since 2015, concomitant therapy with co-trimoxazole for the prevention of Pneumocystis pneumonia has been prescribed only to tracheostomy carriers. When infectious episodes occurred in patients, sirolimus therapy continued without changes in the dose of the drug and did not affect the disease, provided that the therapeutic concentration was maintained. A positive response to therapy was observed in 89.1 % of patients with VA in the form of the size of the vascular mass according to the data of visual examination and instrumental control. All patients showeda clinical response to therapy in the form of relief of painsyndrome, reduction/relief of lymphorrhea, reduction/improvement of hemostasis parameters, and an increase in functional activity and quality. For the entire observation period 2012–2020, when taking sirolimus, not a single severe adverse event occurring in post-transplant patients has been reported that would require discontinuation of the drug. The article presents two clinical cases of sirolimus use in the treatment of patients with kaposiform hemangioendothelioma and extensive venous malformation. Parents are encouraged to use the information in scientific research and publications.