Allogeneic Stem Cell Transplantation (allo-SCT) for Chronic Lymphocytic Leukemia: a Long Term Analysis From the Societe Francaise De Greffe De Moelle Et De Therapie Cellulaire (SFGM-TC).

Abstract 201

Chronic lymphocytic leukemia (CLL) is a common lymphoid malignancy with a heterogeneous natural history. While some patients never require treatment or can be managed effectively with conventional chemotherapy, others experience early disease progression and death. Allo-SCT is increasingly considered as a therapeutic option for younger patients with poor-risk CLL.

This multicenter retrospective analysis assessed the long term outcome of 160 CLL patients who received allo-SCT between 1987 and 2005, and were reported to the SFGM-TC registry.

This series included 127 males (79%) and 33 females (20.6%) with a median age at CLL diagnosis of 45.5 (range, 24.4–65.1) y. The median age at time of allo-SCT was 50.9 (range, 29.8–68.3) y. Before allo-SCT, 26 patients (16.3%) received previous stem cell transplantation in the course of their disease. Patients received either a standard myeloablative conditioning regimen (n=58; 38%; Cy-TBI in 90% of cases) or a so-called reduced-intensity conditioning. A matched-related donor was used in 142 cases (89%) and PBSCs were used as source of stem cells in 92 cases (57.5%). At time of allo-SCT, only 10 patients (6.3%) were in CR1, 17 in CR2 and CR3 (10.6%), 27 in first PR (16.9%) and 106 (66.2%) in more advanced phases, including 46 patients (28.8%) in progressive disease.

With a median follow-up of 60 (range, 1.6–208) months for surviving patients, 96% of patients engrafted (ANC>500/μL) at a median of 18 (range, 1–41) days after allo-SCT. 71 patients (44.4%) experienced grade 2–4 acute GVHD, including 28 cases (17.5%) of grade 3–4 acute GVHD. 73 patients (56.2%) experienced some form of chronic GVHD. At time of last follow-up, 70 patients (43.8%) were still alive, of whom 24 (34%) were in continuous CR. Disease progression accounted for 24 deaths, while transplant-related causes (infections, n=23; GVHD, n=13; MOF, n=12; other causes, n=18) were observed in 66 cases, for a TRM rate of 41%. The KM estimates of disease-free survival (DFS) at 2, 5, and 10 years after allo-SCT were 44.3%, 39.6%, and 30.5%, respectively. Estimates of overall survival (OS) were 54.4%, 46.2%, and 35.8.1%, respectively. In a Cox multivariate analysis for OS (including demographic features, transplant and donor types, and disease status at time of allo-SCT), disease status at time of allo-SCT (CR or PR) was the most significant parameter associated with improved OS (RR=0.56; 95%CI, 0.36–0.89).

We conclude that allo-SCT has the potential to induce long-term disease control and overall survival in patients with high risk or advanced CLL.