PB1922 PONATINIB INDUCES A SUSTAINED DEEP MOLECULAR RESPONSE IN A CHRONIC MYELOID LEUKAEMIA PATIENT WITH AN EARLY RELAPSE WITH A T315I MUTATION FOLLOWING ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION

Abstract

Please indicate where the abstract has been published before: BMC Cancer.Background:Atypical BCR‐ABL1 transcripts are detected in less than 5% of patients diagnosed with chronic myeloid leukaemia (CML), of which e19a2 is the most frequently observed, with breakpoints in the micro breakpoint cluster region (μ‐BCR) and coding for the p230 BCR‐ABL1 protein. p230 CML is associated with various clinical presentations and courses with variable responses to first‐line imatinib.Aims:In the present study we describe in detail the clinical history of a CML patient with a rare e19a2 BCR‐ABL1 transcript who has failed several lines of targeted therapy with tyrosine kinase inhibitors and relapsed after allogeneic hematopoietic stem cell transplantation.Methods:Detailed characterization of the patient's clinical history including therapeutic approach and cytogenetic and molecular analysis.Results:Here we report a case a CML patient with imatinib resistance due to an E255 V mutation, followed by an early post‐transplant relapse with a T315I mutation that achieved a persistent negative deep molecular response (MR5.0) after treatment with single‐agent ponatinib. Using CastPCR, we could trace back the presence of the T315I mutation to all the RNA samples up to the detection of T315 mutation by Sanger sequencing shortly after allogeneic hematopoietic stem cell transplantation.Summary/Conclusion:This case illustrates the major interest of Ponatinib as a valid treatment option for e19a2 CML patients who present a T315I mutation following relapse after allogeneic hematopoietic stem cell transplantation.image