Short Telomeres Before Lenalidomide Treatment Predict Leukemic Progression In Patients with Myelodysplastic Syndrome and Deletion 5q

Abstract 30 Lenalidomide has been shown to induce transfusion independence and cytogenetic response in a high proportion of patients with MDS and isolated 5q deletion (del5q). However, some of these patients progress into acute myeloid leukemia, particularly those who do not show an erythroid or cytogenetic response. Yet the mechanisms inducing the leukemic transformation in patients with MDS and del(5q) are mainly unclear. Since dysfunctional telomeres play an important role in the development of genetic instability and shorter telomeres are associated with advanced MDS and AML, we reasoned whether telomere shortening may contribute to leukemic progression in patients with MDS and del5q. This study included 14 patients with transfusion-dependent anemia and low- or intermediate-1-risk MDS enrolled in the studies MDS-003 (n=42) or MDS-004 (n=260) who were treated with lenalidomide according to the study protocols. Written informed consent was provided according to the Declaration of Helsinki. Seven patients progressed into RAEB-1 or AML while on study and 7 patients did not. Time span between initial diagnosis and study entry was similar (median 51.3 and 44.4 months respectively in the patients with and without leukemic progression). Combined fluorescence R-banding and T/C-FISH analysis to determine the telomere length of each individual chromosome was performed as described earlier (K Lange et al, Genes Chromosomes Cancer, 2010). Telomere length at study entry was 6.1 kb (range 4.8 to 7.9 kb) in patients with MDS and del5q who later underwent leukemic transformation. Patients without later disease progression had a median telomere length of 9.3 kb (range 8.4 to 10.2 kb). Thus, patients who progressed after a median of 29 months (range 5 to 51 months) had significantly shorter telomeres than patients who had a cytogenetic response or stable disease (p Disclosures: Göhring: Celgene Corp.: Consultancy. Giagounidis:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees.