Phase 1 trial of levonantradol in chemotherapy-induced emesis.
Levonantradol is a synthetic cannabinoid with demonstrated preclinical antiemetic activity. The current phase I trial was undertaken to determine: 1) the maximally tolerated dose; 2) the side effects at the different dosage levels; and 3) to evaluate the antiemetic efficacy of levonantradol in patients receiving emesis-producing chemotherapy. Thirty-four patients received 52 courses of levonantradol. Concurrent chemotherapy most frequently consisted of high dose cisplatin (120 mg/m2), either alone or in combination with other agents. Levonantradol dosage was escalated through seven treatment levels (0.5-4.0 mg per dose) and was given intramuscularly every 4 hours. Toxicity was similar to that observed with other cannabinoids and primarily consisted of dizziness (65%), burning and erythema at the injection site (48%), mild sedation (44%), orthostatic hypotension (37%), dysphoria (29%), and urinary retention (10%). Marked urinary retention occurred in three of seven patients at the 4.0 mg per dose level, and two of 24 patients at either the 2.5 mg and 3.0 mg levels. Major or minor antiemetic responses (0-2 or 3-5 emetic episodes, respectively) occurred in 23% of patients receiving cisplatin and in 53% of patients receiving non-cisplatin containing chemotherapy. Intramuscular levonantradol can be given safely at doses up to 3.0 mg/kg, with toxicity and antiemetic efficacy similar to that observed with other cannabinoids.