Omission of day 11 methotrexate does not appear to influence the incidence of moderate to severe acute graft-versus-host disease, chronic graft-versus-host disease, relapse rate or survival after HLA-identical sibling bone marrow transplantation.

Sixty-five patients with haematological malignancy received high-dose chemotherapy or chemoradiotherapy followed by a T replete, HLA-identical sibling bone marrow transplant. All were scheduled to receive a standard cyclosporine/methotrexate immune suppressive regimen to minimise the risk of graft-versus-host disease post-transplant. Forty-six patients received all four scheduled doses of methotrexate, while in nineteen the day 11 dose was omitted due to marked oropharyngeal mucositis or febrile neutropenia. There was a slight increase in the incidence of acute graft-versus-host disease (GVHD) grades I-IV in those not receiving compared to those receiving day 11 methotrexate (84 vs 71% (P = 0.04)). However, there was no difference in the incidence of acute GVHD grades II-IV (14 vs 22%), in the incidence of chronic GVHD (38 vs 47%), in transplant-related mortality (21 vs 24%), in relapse rate (42 vs 51%), in 4-year survival (38 vs 48%), or in disease-free survival (38 vs 42%). These findings suggest that the day 11 methotrexate dose could be omitted without a major deleterious effect on the outcome of HLA-identical sibling marrow transplantation.