The purpose of this study is to determine the feasibility of a larger trial comparing olanzapine and aprepitant and to obtain preliminary data on the effectiveness of these two medications to treat nausea and vomiting in children receiving chemotherapy. Children receiving 2 cycles of chemotherapy with a high risk of causing nausea and vomiting will receive olanzapine in one cycle and aprepitant in another cycle. Children will be randomized to see which medicine they receive first. The investigators will record the number of extra medications used for nausea, the number of times a child vomits, and the amount of nausea the child feels each day.

This will be a pilot study, designed as a randomized, crossover study comparing olanzapine and aprepitant in pediatric oncology patients receiving highly emetogenic chemotherapy (HEC). The primary objective is to determine the feasibility of recruitment and data collection for conducting a larger trial aimed at comparing olanzapine and aprepitant as antiemetic regimens and establishing efficacy of this regimens for pediatric patients receiving HEC. Secondary objectives are to obtain preliminary data regarding the effectiveness of olanzapine and aprepitant as well as the tolerability of olanzapine in the pediatric oncology population.

Each patient must be planned to undergo at least 2 cycles of the same cycle of HEC. Each patient will be randomized to receive olanzapine or aprepitant in the first cycle of chemotherapy, and then will receive the other agent in a second cycle of chemotherapy. Patients will also receive ondansetron and dexamethasone with each cycle. Patients with CNS tumors will not receive dexamethasone. Response will be measured objectively recording number of emesis and use of breakthrough medications. The medications chosen for breakthrough medications will be at the treating physicians discretion. A complete response will be no episodes of emesis or use of breakthrough medications. A partial response is one or less episodes of emesis and one or less use of breakthrough medications. Nausea will be measured based on parent and patient scales and will be a separate measure, not included in the compete or partial response.

Inclusion Criteria:

• age greater than 4 years and less than 21 years

• patient will receive at least two cycles of the same regimen of highly emetogenic chemotherapy

• adequate liver function - defined as total bilirubin less than or equal to 1.5 times the upper limit of normal for age and AST/ALT less than or equal to upper limit of normal for age

• adequate kidney function - defined as creatinine clearance or GFR greater than or equal to 70mL/min/1.73m2 or a serum creatinine based on age/gender as follows: Maximum serum creatinine

  • 2- <6 years: Male & Female 0.8
  • 6- <10 years: Male & Female 1
  • 10- <13 years: Male & Female 1.2
  • 13- <16 years: Male 1.5 Female 1.4
  • >16 years: Male 1.7 Female 1.4

Exclusion Criteria:

• known QTc prolongation or other cardiac arrhythmia
• current treatment with another antipsychotic (for example: risperidone, quetiapine, clozapine)
• prior adverse reaction to either olanzapine or aprepitant
• the planned two cycles of chemotherapy include ifosfamide (a patient may receive ifosfamide as a part of his/her overall treatment plan but not during study cycles)

This trial was a pilot study, limited by numbers of participants. Given the small numbers, during randomization (with 50/50 chance each subject randomized to group A or B) a disproportionate number of patients were randomized to group A.