Early Antithymocyte Globulin Therapy Enhances Survival in Steroid-Resistant Acute GVHD Patients

A comprehensive review of 79 hematopoetic stem cell transplant (HSCT) patients treated with equine antithymocyte globulin (ATG) for steroid-resistant acute GVHD from 1990 to 1998 revealed significant findings. Steroid-resistant acute GVHD was defined as either the progression of acute GVHD after 4 days of prednisone treatment or no improvement after 7 days. The patient cohort included transplants from both related and unrelated donors, with a significant portion suffering from severe (grade III-IV) GVHD prior to ATG therapy.

Treatment involved 1-5 courses of ATG, administered over a median of 16 days, alongside continued prednisone and either CSA or tacrolimus. By day 28 of treatment, 54% of patients showed overall improvement, with 20% achieving a durable complete response and 34% a partial response. Notably, patients with CML or a malignant disease other than acute leukemia were more likely to respond positively to the treatment.

The study highlighted that patients with acute skin GVHD, with or without other organ involvement, responded most favorably to ATG therapy. However, chronic GVHD developed in 51% of patients within a year post-HSCT, and one case of EBV lymphoproliferative disease was reported. The overall survival probability at one year stood at 32%, with factors such as earlier onset of acute GVHD, shorter time from initial GVHD treatment to ATG therapy, and the use of non-T-cell-depleted stem cell grafts associated with better survival outcomes.

These findings underscore the potential of ATG as an effective treatment for steroid-resistant acute GVHD, particularly in patients exhibiting skin GVHD and early signs of steroid resistance.