Cyproheptadine Hydrochloride and Nutritional Supplementation in Treating Young Patients With Weight Loss With Cancer

INCLUSION CRITERIA: * ≥ 2 years and \< 18 years of age at the time of admission to the study * Meets one of the following criteria: * documented history of unintended weight loss \> 5% presumed secondary to cancer/treatment-related therapy within three months * BMI for age less than the 5th percentile * Diagnosed with cancer of any type * Concomitant cancer treatment (surgery, chemotherapy, radiotherapy) guidelines: * Patients who will complete concomitant cancer treatment during this study's 4-week intervention are not eligible * If patients are receiving concomitant cancer treatment, they should be scheduled to get at least another 4 weeks of treatment in order to reach the primary endpoint * If patients have already completed cancer treatment, they need to be enrolled within 8 weeks of completing therapy. * Predicted life expectancy of at least 6 months EXCLUSION CRITERIA: * Currently taking any of the study agents (cyproheptadine hydrochloride (CH), PediaSure, or Ensure) or have taken any of the study agents during the past 3 weeks * History of anorexia nervosa or bulimia * Initiation of other appetite enhancing agents including steroids prescribed for the intent of weight gain, i.e. Megace, is not allowed during this study * Children receiving steroids as part of their daily cancer treatment regimen are excluded from participation. However, intermittent steroid use in an antiemetic regimen or in other pulse steroid therapy is allowed during the study. * Use of other f…