This study was a prospective, randomized, double-blind, parallel controlled clinical trial. The children who met the inclusion criteria and were treated with medium and high emetic chemotherapy drugs were randomly included in the experimental group (forsapitan group) and the control group (placebo group) in the ratio of 1 ∶ 1. The children in the experimental group were infused with fosapitan, dexamethasone and granisetron before chemotherapy, and then continued to be infused with granisetron and dexamethasone until 48 hours after the end of chemotherapy. The antiemetic regimen of children in the control group was placebo instead of fosapitan, and the others were the same as those in the experimental group. In this study, CNNC antiemetic scale and pediatric scale proposed by Dupuis were used to evaluate the vomiting data. The primary end point was the proportion of children who achieved complete remission (CR) in the delayed period (within 24-120 hours after the start of chemotherapy); The secondary end points were the CR rate in the acute phase (within 24 hours after the first chemotherapy administration) and the overall phase. The antiemetic efficacy and adverse reactions of the two groups were observed and analyzed.

Inclusion Criteria:

• children aged 2-12 years at the time of study entry with documented cancer scheduled to receive MEC or HEC (more than 30% emetogenic potential) with Karnofsky score of 60 or more (for patients aged greater than 10 years) or Lansky play performance score of 60 or more (for patients aged 10 years or less) predicted life expectancy of at least 3 months; and written informed consent provided by parent or guardian

Exclusion Criteria:

• vomiting 24 hours before treatment day 1 known history of QT prolongation or allergic reaction to any of the study drugs symptomatic primary or metastatic CNS malignancy causing nausea or vomiting patients who received radiation therapy to the abdomen or pelvis in the week before treatment; active infection or any uncontrolled concurrent illness except for malignancy abnormal laboratory values at screening (peripheral absolute neutrophil count <1000 cells per μL, platelet count <100 000 cells per μL; alanine amino transferase or aspartate aminotransferase >5 times of the upper limit of normal for age, bilirubin or serum creatinine >1.5 times of the upper limit of normal for age) initiation of systemic corticosteroids within 72 hours before study drug administration or as part of the chemotherapy regimen; benzodiazepines or opioids initiated within 48 hours before treatment, except for single doses of triazolam, temazepam, or midazolam use of antiemetics within 48 hours of treatment use of CYP3A4 substrates or inhibitors within 7 days or CYP3A4 inducers within 30 days of treatment