Long-Term Maintenance with Lenalidomide Improves Progression Free Survival In Myeloma Patients with High-Risk Cytogenetics: An IFM Study

Abstract 1944

Cytogenetic abnormalities have been associated with specific outcome in myeloma, as in many other hematologic malignancies. Among the large spectrum of chromosomal changes observed in myeloma, at least two of them are clearly associated with a specific poor outcome, both in terms of PFS and OS, i.e., t(4;14) and del(17p). Recent data suggested that bortezomib can at least partially overcome the prognostic value of t(4;14). However, t(4;14) remains a prognostic factor in the IFM series. Deletion 17p is rare (< 10%), but is associated with a very poor outcome, whatever the treatment proposed to these patients. In 2005, the IFM designed a clinical trial aiming to test the role of lenalidomide maintenance until relapse in patients under 65 years of age treated with a VAD or bortezomib/dexamethasone induction, followed by high-dose melphalan. Six hundred and fourteen patients have been enrolled, and the clinical results of this trial are presented in another abstract. Chromosomal data focused on t(4;14) and del(17p) were available for 488 of those patients, as analyzed at diagnosis by FISH on sorted plasma cells. The t(4;14) was observed in 13.3% of the patients and del(17p) (defined by presence in at least 60% of the plasma cells) was present in 6.6% of them, incidences that are in agreement with previous reports. The median PFS (calculated from the date of randomization) for patients with t(4;14) were 15 months and 27 months for patients in the placebo and lenalidomide arms, respectively. The median for patients with del(17p) were 14 months and 29 months for patients in the placebo and lenalidomide arms, respectively. The comparison of PFS in the lenalidomide arm for patients with t(4;14) or del(17p), as compared with those lacking the chromosomal abnormalities shows a significant difference, in favor of the “no abnormality” group. In conclusion, lenalidomide maintenance very significantly improves the PFS of patients with high-risk cytogenetics, albeit these chromosomal changes retain their prognostic value.