Cephalotaxine Esters: Antileukemic Advance or Therapeutic Failure?

Clinical trials conducted in the People's Republic of China and the United States of the antileukemic efficacy of the cephalotaxine esters are reviewed. Harrington has been incorporated into combination regimens for the treatment of newly diagnosed acute nonlymphocytic leukemia (ANLL) in China, and activity with cephalotaxine esters has also been noted in chronic myelogenous leukemia. While the investigational agent homoharringtonine has shown some activity in the United States in ANLL, investigator interest in the United States has waned because of toxicity and inconvenient schedules. The Chinese trials have used different schedules than have U.S. studies and have been associated with less toxicity. These trials provide new information that may lead to further investigations of the cephalotaxine esters in the United States.