Low- vs High-Dose Sirolimus With Prednisolone for KHE and KMP

Overview

This randomized clinical trial evaluates if low-dose sirolimus (target trough 4-8 ng/mL) combined with prednisolone is noninferior in efficacy but superior in safety compared to standard high-dose sirolimus (target trough 10-15 ng/mL) combined with prednisolone in pediatric patients with kaposiform hemangioendothelioma and Kasabach-Merritt phenomenon (KHE with KMP), with participants randomized 1:1 to receive the assigned regimen, undergo routine blood and imaging monitoring, and be evaluated for clinical response and adverse events.

The goal of this randomized clinical trial is to evaluate if low-dose sirolimus combined with prednisolone is noninferior to high-dose sirolimus combined with prednisolone in managing kaposiform hemangioendothelioma complicated by Kasabach-Merritt phenomenon (KHE with KMP) in pediatric patients. In this study, the low-dose regimen targets a sirolimus trough concentration of 4-8 ng/mL, while the standard high-dose regimen targets a trough concentration of 10-15 ng/mL. The main questions it aims to answer are: Does the combination of low-dose sirolimus (target trough 4-8 ng/mL) and prednisolone achieve a noninferior objective response rate (including platelet count recovery and tumor volume reduction) compared to the high-dose sirolimus (target trough 10-15 ng/mL) and prednisolone combination at the primary endpoint evaluation? Does the low-dose sirolimus combination significantly reduce treatment-related toxicities and adverse events compared to the high-dose sirolimus combination? Researchers will compare a low-dose sirolimus plus prednisolone arm to a standard high-dose sirolimus plus prednisolone arm to see if lowering the sirolimus dose within this combination regimen can maintain comparable therapeutic control over KMP while minimizing dose-dependent adverse effects. Participants will: Be randomized in a 1:1 ratio to receive either oral low-dose sirolimus combined with prednisolone (targeting a trough level of 4-8 ng/mL) or standard high-dose sirolimus combined with prednisolone (targeting a trough level of 10-15 ng/mL). Undergo regular clinical evaluations, including physical examinations and serial blood tests to monitor peripheral platelet counts and sirolimus trough levels. Receive routine imaging studies (such as MRI or ultrasound) to assess changes in tumor volume. Be closely monitored throughout the study period for combination therapy-related side effects and systemic corticosteroid-associated adverse events.