Low-dose cyclosporine of short duration increases the risk of mild and moderate GVHD and reduces the risk of relapse in HLA-identical sibling marrow transplant recipients with leukaemia.

Low-dose cyclosporine (CsA), starting at 1 mg/kg/day i.v. with early discontinuation, and four doses of methotrexate (MTX), was given to 82 consecutive leukaemic patients receiving HLA-identical sibling marrow transplants. Retrospective controls (n = 40) received CsA, starting at 5-7.5 mg/kg/day i.v., given for 1 year, and MTX. In the low-dose group, the risk of acute GVHD grades I-II was 78% as compared to 57% among the controls (P < 0.01). The risk of acute GVHD grades III-IV was 2% and 5%, respectively (NS). Chronic GVHD occurred in 60% in the low-dose group and 24% in the controls (P < 0. 001). Extensive chronic GVHD did not differ between the groups (3% vs6%). In multivariate analyses, low-dose CsA was the only factor associated with acute GVHD grades I-IV (P = 0.02). Significant risk factors for chronic GVHD included low-dose CsA (P = 0.002) and CML (P = 0.03). Transplant-related mortality at 3 years post-BMT was 22% and 19%, in the low-dose group and controls, respectively (NS). The probability of relapse was 26% in the low-dose group and 53% in the controls (P = 0.06). In multivariate analysis, high-dose CsA was the strongest risk factor for relapse (P = 0.03). The 3-year relapse-free survival was 58% in the low-dose group and 43% in the controls (P = 0.1).