GVHD prophylaxis using low‐dose cyclosporine improves survival in leukaemic recipients of HLA‐identical sibling transplants

Graft‐versus‐host disease (GVHD) prophylaxis of short duration (6 months) with low‐dose cyclosporine A (CsA) starting at 1 mg/kg per day i.v. and four doses of methotrexate (MTX) were given to 171 consecutive leukaemic recipients of HLA‐identical sibling transplants. In contrast, apart from MTX, retrospective controls received high‐dose CsA, starting at 5–7.5 mg/kg per day i.v. and discontinued 1 yr post‐transplant. In the low‐dose CsA group, the probability of acute GVHD grades I–II (70% vs. 53%, P < 0.01), and chronic GVHD were increased (58% vs. 25%, P < 0.01), whereas the incidences of acute GVHD grades III–IV (9% vs. 5%, P = 0.62), and non‐relapse mortality (20% vs. 22%, P = 0.58) were similar. Moreover, the probability of relapse was decreased (31% vs. 54%, P < 0.01), and both relapse‐free (56% vs. 38%, P = 0.04) and overall survival (61% vs. 40%, P = 0.04) were markedly improved using the low‐dose CsA regimen. In multivariate analyses, low‐dose CsA was strongly associated with chronic GVHD relative hazard (RH) 2.56, P < 0.01], which decreased the risk of relapse (RH 0.46, P < 0.01) and improved the probability of survival (RH 1.84, P < 0.01). In conclusion, a low‐dose CsA regimen in leukaemic recipients of HLA‐identical sibling transplants increases the rate of chronic GVHD, which seems to attenuate the risk of relapse, thereby improving patient survival owing to enhanced graft‐versus‐leukaemia effect.