Patients who relapse in their battle with acute myeloid leukemia (AML) may benefit from a phase III study of therapies that combine an existing agent, cytarabine, with a newer compound, vosaroxin. These findings were presented at the 56th annual meeting of the American Society of Hematology in San Francisco, California.

The study demonstrated increased survival rates, particularly in patients with AML patients older than 60 years. It was led by Farhad Ravandi, MD, professor of medicine, department of leukemia at The University of Texas MD Anderson Cancer Center in Houston.

Acute myeloid leukemia is the most common form of adult leukemia. The current accepted treatment, cytarabine, when used with other existing agents such as anthracyclines, is associated with increased toxic side effects.

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The 124-site international randomized trial was among the largest of its kind. It demonstrated that combination therapy employing the agent cytarabine with others such as vosaroxin does not cause the significant toxic side effects experienced when cytarabine is used in combination with anthracyclines.

“Currently there are no standard-of-care approved treatments for relapsed or treatment-resistant AML. Effective and safe therapies are critically needed for patients with relapsed or treatment-resistant acute myeloid leukemia” said Ravandi.

“These data provide encouraging support that this combination may be an effective new salvage therapy in older patients with this challenging condition.”

Toxic side effects from combining cytarabine with anthracyclines or topoisomerase inhibitors can include damage to the heart muscle. By combining cytarabine with new agents, researchers hope to develop an effective treatment for AML that does not cause significant additional toxicity.

One such agent is vosaroxin, an agent that can target and evade the cancer cell’s natural defenses and help induce cancer cell death. Researchers have investigated this compound in a phase III randomized trial to evaluate its ability to overcome the limitations of current therapies without the cardiotoxicities commonly observed with other treatments.

In the trial, 711 patients with relapsed or hard-to-treat AML at 124 sites worldwide were randomized to receive cytarabine with either vosaroxin or placebo. Patients treated with vosaroxin achieved longer overall survival compared with those treated with placebo (7.5 months vs 6.1 months) and were more likely to achieve complete response or remission to the treatment (complete response achieved in 30.1% in the vosaroxin arm vs 16.3% in the placebo arm).

Significantly, patients age 60 years or older and those experiencing early relapse experienced the greatest overall survival benefit from the treatment. Early mortality was similar in the two arms, and the most common adverse events were neutropenia, sepsis, and infections as well as mouth sores.