Research Shows Survival Benefit For Leukemia Patients Treated With Arsenic Trioxide

Bayard Powell, M.D., principal investigator of the study and professor and section head of Hematology and Oncology at Wake Forest University Baptist Medical Center, presented the findings today at the annual meeting of the American Society of Clinical Oncology (ASCO).

Nearly 600 patients in the U.S. and Canada participated in the phase III study over a six-year period -- from June 1999 through March 2005. The study was sponsored by the National Cancer Institute (NCI) and led by one of its cooperative groups, the Cancer and Leukemia Group B (CALGB). The Comprehensive Cancer Center at Wake Forest University is a member of CALGB.

"Patients receiving the arsenic trioxide had a significantly higher likelihood of remaining disease-free, with longer survival than those receiving standard chemotherapy alone," said Powell. "The results are so compelling that we recommend use of arsenic trioxide in first-line treatment of APL."

APL is a cancer of the bone marrow in which cancerous cells eventually crowd out the healthy blood cells needed for the body to function normally.

Karen Shelton, a 58 year-old nurse from Kannapolis, was diagnosed with APL in 2001. Ms. Shelton was offered the opportunity to participate in the arsenic trioxide trial. "I was eager to take part in the study. Even if it didn't help me, it might help others," she said. She was one of 26 patients enrolled through Wake Forest Baptist.

In remission for nearly six years, Shelton is an advocate of the therapy. "I truly believe chemotherapy put me in remission, but the arsenic therapy sealed the deal."

Arsenic trioxide was approved by the Food and Drug Administration nearly seven years ago for use in patients with APL who had not responded to, or had stopped responding to, standard first-line therapy.

Approximately 81 percent of patients with APL who received arsenic trioxide were alive and remained in remission -- free of leukemia -- three years after diagnosis compared to 66 percent of patients treated with the standard regimen of chemotherapy. The enhanced effectiveness of the experimental combination also resulted in better overall survival after three years among 86 percent of the patients who received the arsenic trioxide regimen, compared to 79 percent for patients on the standard treatment.

"Up to 30 percent of patients with APL will relapse from current first-line therapy, so finding more effective therapies that enhance overall survival and keep patients in remission is critical," said Powell. "This study represents a major step forward in the treatment of patients with this type of leukemia and reinforces the important role clinical trials play in unlocking new or different combinations of therapies to fight cancer, not to mention the hope it gives patients and their families."

Powell said the willingness of patients with leukemia and their physicians to participate in the clinical trial has markedly improved the outcome for participants and future patients with APL.

Study participants underwent extensive follow-up (32 months on average), including weekly blood tests and regular bone marrow tests. Arsenic trioxide appeared to be well tolerated and did not increase toxicities compared to the standard chemotherapy regimen. Patients participated through one of five NCI-sponsored North American Cooperative Oncology Groups.