The status of antithymocyte globulin therapy for adult patients in Japan: retrospective analysis of a nationwide survey.

We conducted a nationwide survey on antithymocyte globulin (ATG) therapy for adult patients in Japan. We mailed questionnaires to 454 hospitals with hematology divisions, of which 181 (40%) responded, and the records of 448 patients were collected. Patient characteristics, hematological responses, and adverse effects were evaluated in 421 patients with sufficient data. A total of 366 patients had idiopathic aplastic anemia (AA), 29 had other types of AA, and 25 had other diseases. The response rate (RR) at 6 months was 54% for all patients, and 53% for those with idiopathic AA. Ten patients (2%) died within 30 days, and 11 (3%) died between 31 and 100 days after ATG therapy. In 346 patients with moderate to very severe AA, who received their first ATG therapy, factors that influence the outcomes of ATG therapy were extracted. Among 11 pre-treatment and therapy-related variables, three were found to be correlated with a higher RR: shorter duration of AA, no history of specific therapy for AA, and the use of CsA. Most notably, the RR of patients treated within 3 months of diagnosis, those between 3 months and 2 years, and those later than 2 years were 68% (130/190), 48% (54/113), and 13% (5/38), respectively.