Safety of a Three-Day Fosaprepitant Regimen for the Prevention of Chemotherapy-Induced Nausea and Vomiting in Pediatric Participants (MK-0517-045)

Inclusion Criteria: * Is receiving a moderately or highly emetogenic chemotherapy agent/regimen or a chemotherapy agent/regimen not previously tolerated due to vomiting * Has a Lansky Play Performance score ≥60 (participants ≤16 years of age) or a Karnofsky score ≥60 (participants \>16 years of age) * Has a pre-existing functional central venous catheter available for study treatment administration * Is fosaprepitant naïve * Has a predicted life expectancy ≥3 months * A female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions applies: is not a woman of childbearing potential (WOCBP) OR is a WOCBP and agrees to not be sexually active or use a highly effective contraceptive method for at least 28 days prior to receiving study treatment, during the treatment period, and for at least 30 days (or local standard of care if longer) after the last dose of study treatment (including the optional cycles) * Has a negative highly sensitive pregnancy test (urine or serum as required by local regulations) prior to the start of fosaprepitant administration in a given cycle if a WOCBP * Weighs at least 6 kilograms (kg) Exclusion Criteria: * Will receive stem cell rescue therapy in conjunction with a study-related course of emetogenic chemotherapy or during the 14 days following administration of fosaprepitant * Is currently a user of any recreational or illicit drugs or has current evidence of drug or alcohol abuse or dependence as determined by the investigator * Is mentally incapacitated or has a significant emotional or psychiatric disorder that, in the opinion of the investigator, precludes study entry * Is pregnant or breast feeding * Is allergic to fosaprepitant, aprepitant, or prescribed 5-HT3 antagonist * Has an active infection (eg, pneumonia), congestive heart failure, bradyarrhythmia, any uncontrolled disease (eg, diabetic ketoacidosis, gastrointestinal obstruction) except for malignancy, or has any illness which in the opinion of the investigator, might confound the results of the study or pose unwarranted risk in administering study treatment or concomitant therapy to the participant * Is a WOCBP who has a positive pregnancy test at screening (Cycle 1) or on Day 1 of optional Cycles 2 or 3 * Has been started on systemic corticosteroid therapy within 72 hours prior to study treatment administration or is expected to receive a corticosteroid as part of the chemotherapy regimen. Exceptions apply * Is taking excluded medications * Has ever participated in a previous study of aprepitant or fosaprepitant or has taken a non-approved (investigational) drug within the last 4 weeks * Has a known history of QT prolongation or is taking any medication that is known to lead to QT prolongation