to evaluate the safety and efficacy of Low-dose sirolimus in Kaposiform Hemangioendothelioma in Chinese children by a prospective, randomized open trial.

The clinically commonly used dose of sirolimus for Kaposiform Hemangioendothelioma is 0.8 mg/m2 administered twice daily, and the blood concentration can be maintained at 10-15 ng/ml according to the pharmacokinetic formula.Related research reports that maintaining low blood concentration of sirolimus is effective in the treatment of certain vascular malformations and hemangioma, and complications are less. In the clinical practice, we found that the blood concentration was maintained at 7-10 ng/ml, and the patients still achieved good results and the chance of infections decreased. Therefore, this clinical trial was designed.In this trial, two different dosing regimens with corresponding blood concentration were designed to compare the safety and efficacy.In the high concentration group, the sirolimus dosage was adjusted monthly to achieve trough levels between 10 and 15 ng/mL(excluding 10 ng/ml), and it is still used at 0.8 mg/m2 administered twice daily.The low concentration group is 7-10 ng/ml (including 10 ng/ml), and the initial use of sirolimus is 0.7mg/m2 administered twice daily.The dose was adjusted according to the formula after two weeks.The follow-up and evaluation were performed according to a strictly established follow-up schedule after taking the drug.

Inclusion Criteria:

• Kaposiform Hemangioendotheliomas with or without Kasabach-Merritt Phenomenon.
• 0 - 12 years of age at the time of study entry.
• Male or female.
• Consent of parents (or the person having parental authority in families): Signed and dated written informed consent.

Exclusion Criteria:

• with hematological diseases.
• with other solid tumors.
• with hypertension, diabetes, adrenal insufficiency, neurological diseases, liver and kidney dysfunction, and cardiopulmonary insufficiency.
• with tuberculosis,cytomegalovirus and Epstein-Barr virus infection before the treatment.