• Oncology Clinical Trials
• Leukemia

Arsenic trioxide is an effective and indicated agent for relapsed acute promyelocytic leukemia (APL). A study now demonstrates that arsenic trioxide has clinical benefit for patients with newly diagnosed APL. Bayard L. Powell, MD, the Comprehensive Cancer Center of Wake Forest University reported findings from the study in which arsenic trioxide was given as consolidation therapy to patients with APL who had complete remission following standard induction therapy.

The study involved 480 adults (15–79 years old) and 57 children (<15 years old). Adult patients who had complete or partial remission after induction therapy were randomly assigned to receive two 25-day courses of arsenic trioxide (0.15 mg/kg/day) as a first consolidation therapy (followed by standard consolidation therapy; n=243) or to receive standard consolidation therapy (n=237). Children received the same induction therapy and standard consolidation therapy; arsenic trioxide was not offered to children because its safety had not been defined in this population at the time of accrual to the study. Data on children were analyzed separately.

The estimated 3-year event-free survival rate was significantly better for patients who received consolidation therapy with arsenic trioxide (81% vs 66%; p=0.0007). The estimated overall survival rate was also significantly better for this group of patients (86% vs 79%; p=0.063). The 3-year event-free and overall survival rates for the group of children were not significantly different from those for adults who did not receive arsenic trioxide (62% and 86%, respectively).

The response rate was similar for all patients (adults and children). Dr. Powell noted that the rate of complete remission was significantly lower for patients who had high-risk disease (defined as a white blood cell count of more than 10,000) compared with the rate for patients with low- or intermediate-risk disease. In addition, the rate of death during induction and the relapse rate (within 1 year) were higher for patients with high-risk APL. “There were a substantial number of early events during induction, but once patients achieved remission, the shapes of the curves are similar for all three groups,” Dr. Powell explained.

Dr. Powell said that treatment with arsenic trioxide was associated with acceptable toxicity. Grade 4 hematological toxicity occurred during consolidation therapy in 55% of patients treated with arsenic trioxide and in 67% of patients who received only standard consolidation therapy. Grade 4 nonhematological toxicity occurred in 5% of patients in both groups.

• © 2007 MD Conference Express