Meiri, E., Jhangiani, H., Vredenburgh, J.J., Barbato, L.M., Carter, F.J., Yang, H.M., Baranowski, V. (2007). Efficacy of dronabinol alone and in combination with ondansetron versus ondansetron alone for delayed chemotherapy-induced nausea and vomiting. Current Medical Research and Opinion, 23(3), 533-543.

To compare the effectiveness of dronabinol alone or in combination with ondansetron versus ondansetron alone for delayed, chemotherapy-induced nausea and vomiting (CINV) among patients receiving highly emetogenic chemotherapy (HEC) or moderately emetogenic chemotherapy (MEC) in multiple cancer centers

• The study took place over five days.
• Participants were randomized to four treatment groups: dronabinol alone, ondansetron alone, combination with both drugs, and placebo. 
• Standard pretreatment medications, fixed doses on day 2, and flexible doses days 3-5 were administered.
• Participants were assessed based on patient telephone diary entries. Each morning, patients reported symptoms from the previous day via the Interactive Voice Response System.

• The study consisted of 64 participants, aged 18 years or older, with a malignancy that did not involve bone marrow.
• Participants were undergoing chemotherapy regimens and had performance statuses of 0–2 at screening. They could be receiving concurrent radiation except to the abdomen and changing regimens with last antiemetics seven days prior to study enrollment.
• For women, a negative pregnancy test at baseline was required.
• Diagnoses involved primary malignancy of the brain, spinal cord, or nervous system; brain metastases; severe brain trauma or surgery; leukemias; or lymphomas.
• Patients who had used marijuana within 30 days or antiemetics within 7 days were excluded from the study.

The study was conducted at multiple cancer centers.

This was a randomized, double-blind, placebo-controlled, parallel-group study.

The following measurement instruments were used.

• Visual analog scale (VAS)
• Total response
• Intensity of nausea
• Eastern Cooperative Oncology Group (ECOG) performance status
• McCorkle Symptom Distress Scale

Difficulties in enrollment led to early termination of this study.

• The efficacy of dronabinol alone was comparable with ondansetron for the treatment of delayed CINV in patients with cancer receiving HEC or MEC.
• Combination therapy with dronabinol and ondansetron was not more effective than either agent alone.

• Patients had difficulties with potential for randomization to placebo when receiving HEC or MEC.
• Early discontinuation of the study reduced the number of participants enrolled in each treatment group.
• The population was heterogeneous.
• No control chemotherapy treatment was used.
• The majority of patients had breast or lung cancer.