Efficacy and Safety of Fosaprepitant Dimeglumine in Preventing Chemotherapy-Induced Nausea and Vomiting (MK-0517-031)

Inclusion Criteria: * Has a histologically or cytologically confirmed malignant disease * Is naive to moderately and highly emetogenic chemotherapy * Is scheduled to receive a single IV dose of one or more MEC agents on Day 1, except for the combination of anthracycline and cyclophosphamide * Has a predicted life expectancy of at least 4 months, and a Karnofsky score of at least 60 indicating that the participant requires occasional assistance, but is able to care for most of his/her needs. * Female of childbearing potential demonstrates a negative urine pregnancy test, and agrees to remain abstinent or use two acceptable forms of birth control for at least 14 days prior to study, throughout the study, and at least 1 month following last dose of study drug. Exclusion Criteria: * Has vomited in the 24 hours prior to treatment Day 1 * Has symptomatic primary or metastatic symptomatic central nervous system malignancy causing nausea and/or vomiting * Is scheduled to receive chemotherapy agent classified as highly emetogenic * Has received or will receive total body irradiation, or radiation therapy to the abdomen, pelvis, head and neck in the week prior to Treatment Days 1 through Day 6 of the Treatment Period * Has illness or history of illness which might confound study results or pose unwarranted risk * Known history of QT interval prolongation * Uses illicit drugs or abuses alcohol * Mentally incapacitated or has a significant emotional or psychiatric disorder * History of hypersensitivity to aprepitant, ondansetron or dexamethasone * Pregnant or breast-feeding * Has participated in a study with aprepitant or taken a non-approved (investigational) drug within the last 4 weeks * Has concurrent condition, such as systemic fungal infection or uncontrolled diabetes, that precludes administration of dexamethasone.