Cyproheptadine in Preventing Weight Loss in Children Receiving Chemotherapy for Cancer

OBJECTIVES: Primary * To determine the effect of cyproheptadine hydrochloride in the prevention of cancer- or treatment-related weight loss (defined as ≥ 5% reduction in weight from baseline measurement) in children who are initiating a course of moderately or highly emetic chemotherapy. Secondary * To investigate the effect of cyproheptadine HCl on the change in weight for age scores after 8 weeks of study drug administration in comparison to placebo. * Investigate the relationship between the secondary outcome variables (prealbumin, triceps skin fold, mid-upper arm circumference, and weight loss)from baseline to end of treatment in each group (treatment and placebo) separately. OUTLINE: This is a multicenter study. Patients are stratified according to enrolling center and steroid use with cancer treatment (yes vs no). Study agent can start anytime up to and including day 28 after the first dose of chemotherapy. * Arm I: Patients receive oral cyproheptadine hydrochloride twice daily for 8 weeks. * Arm II: Patients receive an oral placebo twice daily for 8 weeks. Patients undergo weight and height measurements at baseline and at each follow-up visit in weeks 4 and 8 to evaluate the effect of cyproheptadine hydrochloride and duration of response. Patients or parents complete medicine logs at each follow-up visit in weeks 4 and 8 to evaluate drug compliance and tolerance. Patients also undergo measures of nutrition; and measures of body composition, lean body mass, and fat percentage using standardized equipment and procedures for measuring triceps skin fold and mid-arm muscle circumference at baseline and at the end of the study. Patients undergo blood sample collection at baseline and at the end of the study for biomarker studies. Samples are analyzed for pre-albumin levels.