Second transplant for leukaemic relapse after bone marrow transplantation: higher early mortality but favourable effect of chronic GVHD on continued remission

Ninety second bone marrow transplants (BMT) for relapsed leukaemia were carried out in 30 European BMT centres. At second BMT, after further treatment in 64 cases, 43 patients were in complete remission or in chronic phase of CML, and 47 were in continuing relapse, accelerated phase or blast crisis of CML. Seventy patients died, 37 from early transplant-related toxicity and relapse or failure to eradicate leukaemia which occurred in 23. There were 20 survivors. The actuarial disease-free survival was 11% with a relapse probability of 69% at 3 years. Associated with reduced graft-versus-host disease (GVHD) prophylaxis during second BMT, the incidence and severity of acute and chronic GVHD, was increased when compared with the first BMT (P = 0.02, and 0.002 respectively for acute and chronic GVHD). In multivariate analysis survival was shown to be favoured by a prolonged interval between first and second BMT (relative risk 1.3/year, P = 0.02), and no or mild chronic GVHD following first BMT (relative risk 2.3, P = 0.02). Continuing remission was favoured by chronic GVHD occurring after second BMT (relative risk 8.1, P = 0.004). These results confirm the high treatment-related mortality following second BMT, but identify superior survival in selected patients. Improved results might be achieved by further reduction in preparative regimen intensity, and increasing graft-versus-leukaemia reactivity.