OBJECTIVES:

Primary

• Compare the efficacy of standard antiemetic therapy comprising ondansetron and dexamethasone combined with either aprepitant or placebo in controlling nausea and vomiting, as determined by the number of retch/emesis-free days, in patients undergoing hematopoietic stem cell transplantation.

Secondary

• Determine the safety of aprepitant in these patients.
• Compare nausea, appetite, taste changes, nutritional intake, and mucositis in patients treated with these regimens.
• Determine the pharmacokinetics of cyclophosphamide, carboxyethylphosphoramide mustard, hydroxycyclophylamide, and aprepitant in these patients.

OUTLINE: This is a randomized, placebo-controlled, single-blind, pilot study. Patients are randomized to 1 of 2 treatment arms.

• Arm I: Beginning on the first day of conditioning chemotherapy, patients receive oral aprepitant once daily and standard antiemetic therapy comprising oral or IV ondansetron and oral dexamethasone.
• Arm II: Patients receive oral placebo once daily and standard antiemetic therapy as in arm I.

In both arms, treatment continues until day 4 after stem cell transplant in the absence of unacceptable toxicity.

After completion of study therapy, patients are followed until day 18.

PROJECTED ACCRUAL: A total of 40 patients (20 per treatment arm) will be accrued for this study.