Phase I study of thalicarpine (NAC-68075), a plant alkaloid of noval structure.

An initial clinical trial of daily and weekly X 6 ihtravenous infusions of thalicarpine, a plant alkaloid of novel structure, was carried out in 36 patients. Twenty-eight patients received 33 courses of single-dose administration at doses of 200-1900 mg/m2. At the maximum tolerable dose of 1400 mg/m2, toxic effects included arm pain (nine or ten), central nervous system depression (seven of ten), nausea and vomiting (two of ten), hypotension (two of ten), hypertension (two of ten), arrhythmia (premature ventricular contractions) (one of ten), and electrocardiographic changes (mainly T-wave flattening) (five of ten). At the maximum tolerable dose for weekly administration, 1100 mg/m2/week X 6, arm pain was seen in seven of eight, central nervous system depression in three of eight, hypotension in one of eight, and electrocardiographic changes in three of eight. The recommended dose for phase II trials is 1100 mg/m2/week by a 2-hour intravenous infusion.