Combination Therapy of Severe Aplastic Anemia

Severe acquired aplastic anemia (SAA) has a poor prognosis if untreated. Bone marrow transplantation is available to only a minority of patients due to lack of a matched sibling donor, advanced age of the patient, or cost. Clinical studies at NIH and elsewhere have demonstrated excellent response rates and improved survival with immunosuppressive treatments. Laboratory data implicate underlying cytotoxic T-lymphocyte-mediated suppression of hematopoiesis as the likely proximal cause of disease in most patients. In earlier clinical protocols we treated SAA with cyclosporine A (CSA) (86-H-0007), antithymocyte globulin (ATG) (87-H-0124), and combined ATG and CSA (90-H-0146). While intensive immunosuppression is most effective, relapse is common and some patients also develop second hematologic complications like myelodysplasia. In this protocol, we modify our regimen by delaying the introduction of cyclosporine to promote ATG tolerizing effects and adding mycophenolate mofetil (MMF), a new agent that, like ATG may be relatively specific for activated lymphocytes, in an effort to reduce the high relapse rate.

• INCLUSION CRITERIA:

Only patients with SAA will be admitted, defined as:

Bone marrow cellularity less than 30%.

At least two of the following blood count findings: absolute granulocyte count less than 500/mm(3); platelet count less than 20,000/mm(3); reticulocyte count less than 60,000/mm(3).

Age greater than or equal to 1 years.

Weight greater than 12 kg.

Exclusion criteria

Serum creatinine greater than 2 mg/dl or estimated creatinine clearance less than 40 ml/min.

Underlying carcinoma, recent history of radiation or chemotherapy.

Current pregnancy or unwillingness to be treated with oral contraceptives.

Inability to comprehend the investigational nature of the study.

Moribund status or concurrent hepatic, renal, cardiac, neurologic, or metabolic disease of such severity that death within 7 to 10 days is likely.

Evidence of other etiology than AA for bone marrow failure, including positive clastogenic stress cytogenetic assay for Fanconi anemia and marrow chromosome abnormalities typical of myelodysplasia.