Can donor stem cell transplants improve CLL in poor-risk patients?

This study looked at the safety and effectiveness of donor stem cell transplantation in chronic lymphocytic leukemia (CLL) patients who have not responded well to previous treatments. The authors concluded that stem cell transplants can lead to long-term minimal residual disease-free survival for up to one-half of patients.

CLL is a form of leukemia most commonly diagnosed in people over the age of 70. In less severe cases, it is left untreated to minimize the risk of side effects. In more severe cases CLL is usually treated with a combination of chemotherapy and antibodies. Successful treatment can lead to minimal residual disease (when a very small number of cancer cells are left in the body) or remission (no signs of disease).

Some patients may relapse (where the symptoms return) soon after treatment. Other patients do not respond to chemotherapy or antibodies. Alternative treatments are needed for these patients. Stem cell transplants can provide long-term control for CLL, but there are risks involved with the procedure.

Genetic features can indicate if a patient will not respond to different treatments. For example, patients with a genetic alteration (permanent change) called a 17p deletion typically do not respond well to chemotherapy. It is important to identify these features to avoid prescribing unsuitable treatment.

Data was collected from 90 CLL patients (average age of 53 years) who had received a donor stem cell transplant. Stem cell donors were related to the patients where possible or partially matched. Patients were first treated with low doses of chemotherapy.

94% of patients responded to the transplant. 73% achieved remission (no evidence of disease). After a 4 year follow up period, 40% of patients had relapsed. Genetic factors had no effect on survival rates or event-free survival rates. 4-year overall survival (time from treatment until death from any cause) was 65%. After 4 years, 23% had not relapsed and were still alive.

52 patients were monitored for minimal residual disease. Of these, 52% were minimal residual disease free and alive 12 months after transplant.

73% of patients experienced chronic disease directly related to the transplant. One year after the transplant 65% of the surviving patients were still receiving medications to block the immune system.

The most common causes of death were CLL progression, infection, disease related to the transplant and disease of the blood vessels. 

The authors concluded that stem cell transplants can improve CLL in up to one half of patients who have not responded well to previous treatment.

Some of the authors have received funding from the drug companies who produced the treatments used in this study.

Consult with your physician to discuss your suitability for a stem cell transplant.