High-Dose Cyclophosphamide To Treat Severe Aplastic Anemia

Summaries for Patients are a service provided by Annals to help patients better understand the complicated and often mystifying language of modern medicine.

Summaries for Patients are presented for informational purposes only. These summaries are not a substitute for advice from your own medical provider. If you have questions about this material, or need medical advice about your own health or situation, please contact your physician. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the American College of Physicians-American Society of Internal Medicine.

The summary below is from the full report titled "Durable Treatment-Free Remission after High-Dose Cyclophosphamide Therapy for Previously Untreated Severe Aplastic Anemia." It is in the 2 October 2001 issue of Annals of Internal Medicine (volume 135, pages 477-483). The authors are RA Brodsky, LL Sensenbrenner, BD Smith, D Dorr, PJ Seaman, SM Lee, JE Karp, I Brodsky, and RJ Jones.

What is the problem and what is known about it so far?

Aplastic anemia is a disease of the bone marrow. Bone marrow is the material in the center of bones that produces blood cells. Stem cells are the cells in the bone marrow that become red blood cells (cells that carry oxygen), white blood cells (cells that fight infection), and platelets (cells that help blood to clot). In aplastic anemia, the bone marrow does not produce stem cells, resulting in abnormally low numbers of all blood cells. Aplastic anemia is difficult to treat and can be fatal. The best hope for curing the disease has been treatment with the drug cyclophosphamide to destroy the abnormal bone marrow, followed by replacement with normal bone marrow (bone marrow transplantation). Unfortunately, many patients do not have appropriate bone marrow donors, and bone marrow transplantation has many serious complications. An earlier report suggested that some people with aplastic anemia can be free of the disease for long periods after treatment with only high-dose cyclophosphamide and do not require bone marrow transplantation.

Why did the researchers do this particular study?

To further study the safety and results of high-dose cyclophosphamide without bone marrow transplantation in the treatment of severe aplastic anemia.

Who was studied?

The researchers studied 19 patients with severe aplastic anemia at three hospitals.

How was the study done?

The researchers treated the patients with high-dose cyclophosphamide alone and then contacted them regularly to see how they did. Patients with complete remission of aplastic anemia had normal blood counts for their age. Patients with partial remission did not need transfusions, and their white blood counts were out of the danger zone for infection.

What did the researchers find?

On average, it took 49 days for the number of white blood cells to rise above the danger zone for infection. Two years after treatment, 73% of the patients no longer needed transfusions. At 50 months, 65% were in complete remission. Five years after treatment, no patient with complete remission had had relapse or developed another bone marrow disorder.

What were the limitations of the study?

The study did not include a comparison group of patients who were treated with bone marrow transplantation in addition to cyclophosphamide. The study excluded patients who were older than 70 years of age and those who had abnormal kidney function, heart failure, infection, or another cancer. Thus, the results may not apply to these types of patients.

What are the implications of the study?

High-dose cyclophosphamide without bone marrow transplantation may be a useful treatment option for patients with aplastic anemia who cannot have bone marrow transplantation. This treatment option deserves further study.