4CPS-083 Discontinuation of lenalidomide treatment in patients with myelodysplastic syndrome associated with 5q deletion

<h3>Background and Importance</h3> According to OMS-2016, myelodysplastic syndrome (MDS) associated with del(5q) is manifested by a transfusion-dependent progressive bone marrow failure, with Lenalidomide acting as the intended drug to treat this syndrome. <h3>Aim and Objectives</h3> To evaluate the clinical benefit associated to the discontinuation of the Lenalidomide treatment due to side effects or intolerance. <h3>Material and Methods</h3> Five-year prospective observational study on 75 cases of MDS, 30 of them with del(5q). An analysis of the mutational profile was performed by Next-generation sequencing (NGS) to determine cases with high-risk mutational profiles mainly associated with the TP53 variant. Response to treatment can be predicted knowing that it is not recommended to use lenalidomide in patients with MDS (5q) and with the presence of a TP53 mutation because this could favour clonal evolution, expansion of the tumour clone and progression to acute myeloid leukaemia. Treatment discontinuation was studied in those candidates with side effects or intolerance. The variables considered in this study were: beginning of treatment, Lenalidomide mean dose, ending of treatment and beginning of discontinuation, side effects, time after discontinuation, evaluation of the drug withdrawal response. <h3>Results</h3> 75 MDS cases were analysed (58% male and 42% female). 30 cases were detected as MDS associated to del(5q) (40%) and 20% of them showed positive TP53 mutation and were treated with hypomethylating agents instead of Lenalidomide. 65% of the cases were treated with Lenalidomide, the treatment were discontinued in 32% of them due to side effects and the dose reduced in 23% due to intolerance. The reported side effects were: Grade 4 neutropenia, rhabdomyolysis, erythematous reactions and haemolytic crisis. 100% of patients in which Lenalidomide was discontinued due to side effects, maintained complete haematological and cytogenetic response, reaching a mean monitoring time of 12 months since the withdrawal of Lenalidomide. <h3>Conclusion and Relevance</h3> Discontinuation of Lenalidomide, due to side effects or intolerance, involves a clinical benefit to those patients who maintain a complete haematological response after interruption of the treatment <h3>References and/or Acknowledgements</h3> <h3>Conflict of Interest</h3> No conflict of interest