Tolerability of dronabinol alone, ondansetron alone and the combination of dronabinol plus ondansetron in delayed chemotherapy-induced nausea and vomiting.

8196 Background: Dronabinol (Marinol), the synthetic version of tetrahydrocannabinol, is used to treat nausea and vomiting following cancer chemotherapy (CINV). It has a unique mechanism of action (cannabinoid receptor binding) compared to the more frequently used serotonin receptor antagonists. Tolerability of dronabinol versus ondansetron and the combination of dronabinol plus ondansetron was explored in subjects with delayed CINV.

METHODS:

Subjects receiving moderate to high emetogenic chemotherapy were randomized in this double-blind, placebo-controlled, flexible-dose study. All subjects received dexamethasone 20mg PO and ondansetron 16mg IV prior to chemotherapy. Subjects in the dronabinol (D), ondansetron (O) and dronabinol plus ondansetron (DO) groups also received dronabinol 2.5mg pre- and post-chemotherapy (Day 1); the placebo (P) group did not. Treatment continued through Day 5. Adverse events (AEs) were coded using the MedDRA dictionary. No statistical testing was conducted on AE rates.

RESULTS:

All 64 randomized subjects were in the safety population.

CONCLUSION:

Dronabinol was well tolerated and resulted in few terminations due to adverse events. The low rate of CNS-related adverse events following D treatment may make it a suitable alternative to serotonin antagonist therapy for delayed CINV. [Figure: see text] [Table: see text].