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Combination of Three Chemotherapy Drugs

Chronic lymphocytic leukemia (CLL) is the most common form of adult leukemia, with more than 7,000 people diagnosed each year in the United States. CLL results from a genetic mutation of bone marrow cells that causes abnormal blood cells to form. The genetic mutation is not present at birth, but for unknown reasons arises later in life. Most people who develop CLL are older than 50.As a group, leukemias account for about 25% of all childhood cancers and affect about 2,200 American young people each year. The condition can be present within a person's body for years without causing significant symptoms. It is sometimes discovered incidentally when a patient undergoes blood tests for another medical condition.

The term leukemia refers to cancers of the white blood cells, which are also referred to as leukocytes or WBCs. When a child has leukemia, large numbers of abnormal white blood cells are produced in the bone marrow. These abnormal white cells crowd the bone marrow and flood the bloodstream, but they cannot perform their proper role of protecting the body against disease because they are defective.

As leukemia progresses, the cancer interferes with the body's production of other types of blood cells, including red blood cells and platelets. This results in anemia (low numbers of red cells) and bleeding problems, in addition to the increased risk of infection caused by white cell abnormalities.

Whilst generally considered incurable CLL progresses slowly in most cases. Many people with CLL lead normal and active lives for many years - in some cases for decades. Because of its slow onset, early-stage CLL is generally not treated since it is believed that early CLL intervention does not improve survival time or quality of life. Instead, the condition is monitored over time.

The decision to start CLL treatment is taken when the patient's clinical symptoms or blood counts indicate that the disease has progressed to a point where it may affect the patient's quality of life. Clinical "staging systems" such as the Rai 4-stage system and the Binet classification can help to determine when and how to treat the patient.

Treatment options for CLL include watchful waiting, chemotherapy, radiation, surgery, transplant and monoclonal antibody therapy. Effective treatments have been developed in recent years that provide new hope to patients.

A combination of three chemotherapy drugs -- pentostatin, cyclophosphamide and rituximab -- produced significant clinical response in patients with previously untreated chronic lymphocytic leukemia, according to a study presented at the American Society of Hematology annual meeting.

Each year, about 10,000 people in the United States are diagnosed with this blood and bone marrow cancer.

"Chronic lymphocytic leukemia is incurable but continues to be made more manageable with the advent of powerful new chemoimmunotherapy tools," lead researcher Dr. Neil E. Kay, a Mayo Clinic hematologist, said in a prepared statement.

"We and our collaborators at Ohio State University... have done previous research on pentostatin that led us to believe there would be success with this (three-drug) regimen, and are pleased with the results," Kay said.

The 64 patients in the study received six cycles of the combined regimen. The patients also received a year of treatment with the anti-infection drug sulfamethoxazole-trimethoprim and the antiviral drug acyclovir.

At the start of the study, the researchers determined that most of the patients had significant disease progression and/or a high expectation of rapid advancement of their disease.

Following treatment, 91 percent of the patients in the study experienced improvement in their condition, including 41 percent who achieved complete response.

"We are very pleased with the results of this study. This is a new, viable option for high-risk patients who might not have had much hope before, and it's especially exciting that it works for patients of all age groups," Kay said.

Determining when to start treatment and by what means is often difficult; studies have shown there is no survival advantage to treating the disease too early. The National Cancer Institute Working Group has issued guidelines for treatment, with specific markers that should be met before it is initiated.