Drug Combo Effective Against Leukemia

July 19, 2007 -- Patients with the most common type of leukemia achieved better responses to treatment with two cancer-fighting drugs than one in a large international study.

Chronic lymphocytic leukemia (CLL) patients also had much better survival rates without disease progression when treated with a combination of the chemotherapeutic drugs fludarabine and cyclophosphamide than patients treated with fludarabine alone or another single-agent chemotherapy, chlorambucil.

The study is the third in two years to find greatly improved clinical outcomes among CLL patients treated with the combination regimen.

Together, the studies show that fludarabine plus cyclophosphamide should be considered a standard, first-line treatment for CLL, Daniel Catovsky, FRCP, of the Institute of Cancer Research in Sutton, England, tells WebMD.

The study appears in the July 21 issue of The Lancet.

"We think the combination should be used both in clinical practice and in clinical trials evaluating new approaches to treatment," he says.

CLL in the U.S.

More than 15,000 new cases of CLL will be diagnosed this year in the U.S., with most cases occurring in people over 50. In addition to advanced age, it is more commonly seen in men.

Because CLL progresses slowly -- sometimes over decades -- and people with early-stage disease have no symptoms, patients are generally not treated until they are in their 70s or older.

In the U.S., patients are often treated with fludarabine (brand name Fludara) or chlorambucil (brand name Leukeran).

In the latest study of CLL drugs, Catovsky and colleagues compared outcomes among patients treated with fludarabine plus the chemotherapy drug cyclophosphamide (brand name Cytoxan), fludarabine alone, or chlorambucil alone.

A total of 777 study participants with previously untreated CLL were followed for up to five years. The average age of the patients when they entered treatment was 65.

While no significant difference in overall survival rates was seen among the three treatment groups, three times as many patients who got the combination treatment experienced no progression of their disease at five years (36% vs. 10% for the two single drugs).

Complete responses to treatment were seen in 38% of patients treated with the two drugs, compared with 15% of patients treated with fludarabine alone and 7% of those treated with chlorambucil alone.

Treatment with fludarabine plus cyclophosphamide was associated with a higher incidence of potentially dangerous declines in infection-fighting white blood cells and more days spent in the hospital during treatment.

Age Shouldn't Dictate CLL Treatment

Overall, the combination treatment was well tolerated, Catovsky says, even among the oldest patients in the study.

The message that older patients with CLL can tolerate the most aggressive treatments is one of the most important to come out of this and other recent studies, says Mayo Clinic College of Medicine assistant professor of medicine Tait D. Shanafelt, MD.

"Patients over the age of 70 who were physically fit did very well with this regimen," he tells WebMD. "Age alone should not be considered a reason to exclude people from aggressive therapy. That is an important message."

Finding appropriate treatments for CLL patients who are not good candidates for the most aggressive therapies because of other health conditions or age-related frailty should also be high on the list, he adds.

"We don't really have a good handle on what the most effective and tolerable treatments are for these patients," he says.

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SOURCES: Catovsky, D. The Lancet, July 21, 2007; vol 370: pp 230-239. Daniel Catovsky, FRCP, Institute of Cancer Research, Sutton, England. Tait D. Shanafelt, MD, assistant professor of medicine, Mayo Clinic College of Medicine, Rochester, Minn.  American Cancer Society.

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