The use of all-trans-retinoic acid (ATRA [Vesanoid]) has revolutionized the treatment of patients with acute promyelocytic leukemia (APL)(Tallman et al: N Engl J Med 337:1021-1028, 1997). However, a significant proportion of patients still relapse and die from their disease. Studies from China have indicated that arsenic trioxide is effective even in patients who did not respond to ATRA, and subsequent research has suggested that it works by a different mechanism of action (Shen et al: Blood 89:3354-3360, 1997).
Studies by Soignet et al (abstract #1992; Soignet et al: N Engl J Med 339:1341-1348, 1998) have confirmed the activity of arsenic trioxide in relapsed patients with APL. A North American trial will soon be underway to better define the role of arsenic in the treatment of APL.