[News in therapeutic management of chronic lymphoid leukemia]

Abstract

Chronic lymphocytic leukemia follows an extremely variable clinical course with survival range from months to decades. Some patients present minimal symptoms and others organomegaly requiring rapidly therapy. Therapeutic options take into account efficacy, toxicity and prognostic factors. One of the well known prognosis factor is the clinical staging developed either by Rai et al. or by Binet et al. However, there is an important heterogeneity concerning the course of the disease among patients within a single stage group. Recently, several important observations related to the biologic significance of VH gene mutational status, expression of CD38, over-expression of ZAP-70 and chromosomal aberrations have led to the ability to identify high risk patients with rapid disease progression and lower survival. It has been demonstrated that the VH mutation status is clinically highly relevant. CLL patients with unmutated VH gene show an unfavourable course with a very rapid progression. Specific genomic aberrations have been associated with disease characteristics such as lymphadenopathy related to 11q deletion and resistance to treatment related to 17p deletion. VH gene mutation status and genomic aberrations appear separate parameters when considering their prognostic relevance but nevertheless they are correlated: unfavourable aberrations (11q- and 17p-) occur more frequently in VH unmutated CLL patients. According to these prognostic factors, several treatments including purine analogues and/or monoclonal antibodies have been tested with different schedules and doses of monoclonal antibodies (rituximab and alemtuzumab) considering safety to determine the better efficacy. Infections and haemolytic anemia remain the most frequent complications during conventional chemotherapy. In autologous transplant setting, the transplant related mortality is less than 10%, but survival curve do not show a plateau with about 50% of patients relapsing at 4 years. Conventional allogeneic transplantation could achieve durable remission and probably cure the disease but at the price of a too high transplant related mortality related to depressive immune status and old age of CLL population. In order to minimize the toxicity and to improve graft-versus-leukemia effect, development of reduced intensity conditioning (RIC) regimens appear particularly important for CLL patients. Recent studies, although a still short follow-up show very promising results and use of monoclonal antibodies in the conditioning or just after transplant could improve the results of allogeneic stem cell transplantation and cure a larger number of CLL patients. Recent advances to categorize CLL patients according to risk stratification regarding new prognostic factors (FISH, CD38, ZAP70, Ig mutational status) should allow to define better the best therapeutic strategy. In parallel, age, co morbidities and the notion of the risk-adapted strategy have also an important impact adding.