A survey of the effectiveness of cyclophosphamide in patients with severe aplastic anemia.

The members of the American Society of Hematology were surveyed to determine their experience in the treatment of patients with severe aplastic anemia (AA) with cyclophosphamide (CYT). Among the 401 members responding, 50 had treated AA patients, and three remissions were reported. These remissions can be explained either by response to CYT in a subgroup of patients with AA due to an immune mechanism or to spontaneous remission. Clinical trials of the efficacy of cytotoxic drugs in the treatment of AA patients will not likely permit a distinction between drug effect and spontaneous remission until the subgroup of patients with immune-mediated AA is identified through the development of more sensitive and specific in vitro tests.