Russian Prospective Non-Randomized Clinical Study on Dose Reduction of Tyrosine Kinase Inhibitors with Subsequent Complete Therapy Discontinuation in Chronic Myeloid Leukemia Patients with Stable Deep Molecular Response (READIT-2020): Background, Aim, Main Objectives, Design, and Expected Results

Abstract

Background. A withdrawal of tyrosine kinase inhibitor (TKI) therapy in chronic myeloid leukemia (CML) patients with optimal response, especially in patients with drug toxicity, is a matter of current interest. According to the results of numerous clinical studies, the probability of sustaining treatment-free remission (TFR) in CML patients with deep molecular response (DMR) is about 40-60 %. Great attention has recently been paid to personalized therapy consisting in TKI dose modification aimed at reducing or preventing therapy adverse events. Many large retrospective studies showed that reduced TKI doses in CML patients with major molecular response (MMR) and DMR is a safe therapy option. The follow-up of patients receiving reduced TKI doses is also carried out under prospective clinical studies as a stage prior to therapy discontinuation. This approach shows that the probability of sustaining TFR after the stage of TKI dose reduction is about 70 % which is higher than that after the withdrawal of standard TKI doses. Aim. To present the background, aim, and mai n objectives of the study as well as the design and expected results. Materials & Methods. READIT-2020 (Russian prospective study of REduction And DIscontinuation Treatment of TKI) is a Russian prospective non-randomized clinical study with the main aim of developing a safe management regimen for CML patients with MMR and DMR, who receive reduced TKI doses, with subsequent follow-up in the period of TFR under the control of minimal residual disease. The study is going to enroll 100 patients. Each stage of the clinical study will include a regular molecular genetic monitoring at the central laboratory (National Research Center for Hematology, Moscow). The primary objective is to assess survival without MMR loss (BCR-ABL > 0.1 %) both on reduced TKI doses and during TFR. The primary endpoint is the follow-up period of 12 months after TKI discontinuation. Trial Registration No.: NCT04578847 (Clinicaltrial.gov).