Omission of day+11 methotrexate after allogeneic bone marrow transplantation is associated with increased risk of severe acute graft-versus-host disease

The combination of CYA and short-course MTX is commonly used for GVHD prophylaxis after allogeneic BMT. Severe mucositis and organ dysfunction early after transplantation often lead to omission of the day +11 dose of MTX. To examine whether this omission increases the risk of acute or chronic GVHD, we reviewed 135 allogeneic BMTs performed at our institution in which CYA and short-course MTX prophylaxis were used. Patients receiving less than three doses of MTX and those who died before day +11 were excluded. Of the 123 eligible patients, 84 received all four doses and 39 received three doses, with the fourth dose withheld because of severe mucositis (n = 27) or hepatic or renal dysfunction (n = 12). Acute GVHD of any grade developed in 23 patients (59%) in the threedose group compared with 57 patients (68%) in the four-dose group (P = 0.33). Chronic GVHD developed in 15 patients (38%) in the three-dose group compared with 31 patients (37%) in the four-dose group (P = 0.87). There was no difference in the overall rate of acute or chronic GVHD between the groups. However, the three-dose group was more likely to develop grade III or IV acute GVHD (12 of 39 (31 %)) compared with the fourdose group (12 of 84 (14%); P = 0.03). Relapse-free survival was similar for the two groups. We conclude that omitting day +11 MTX appears to increase the risk of severe acute GVHD.