Arsenic Compound Helps Patients with Rare Leukemia Live Longer

June 2, 2007

Adding arsenic trioxide (Trisenox) to standard treatment significantly extends the lives of adults with newly diagnosed acute promyelocytic leukemia (APL), according to a new study. APL is a subtype of acute myeloid leukemia (AML) and accounts for about 1,500 cases in the United States each year. It is most often diagnosed in young and middle-age adults.

Standard treatment for APL involves three stages known as induction, consolidation, and maintenance therapy. Induction therapy is given first to eliminate all of the leukemia cells. Consolidation therapy helps destroy any remaining leukemia cells after successful induction therapy, and maintenance therapy is given to keep the cancer from returning.

In this phase III clinical trial, 257 adults received the standard consolidation treatment, and 261 adults received two courses of arsenic trioxide in addition to the standard consolidation treatment. After three years, 86% of the patients who received arsenic trioxide were alive compared with 77% of the patients who received only the standard therapy. In addition, the leukemia did not relapse (come back) during this three-year period in 77% of the patients who received arsenic trioxide, compared with 59% of patients who received the standard treatment.

The side effects included heart irregularities and lowered blood counts, which were similar between the two groups. More patients taking arsenic trioxide experienced infections and headaches (43%) than the patients who did not receive the arsenic trioxide (28%).

What This Means for Patients

Arsenic trioxide is currently used as a second treatment when the standard therapy is no longer effective. "The data from this study are important enough to justify including arsenic trioxide in the initial treatment of APL," said Bayard L. Powell, MD, Professor of Hematology and Oncology at Wake Forest University Baptist Medical Center in North Carolina and the study's lead author. "Arsenic trioxide has already shown great benefits as a second-line treatment for APL, a cancer for which patients previously had few good treatment options. This study shows that even more patients will benefit if we give it earlier in the course of treatment."