PB1688 SUCCESSFUL HAPLOIDENTIC BONE MARROW TRANSPLANTATION WITH INOTUZUMAB OZOGAMICIN IN PATIENT WITH RELAPSED AND RESISTANT B CELL ACUTE LYMPHOBLASTIC LEUKEMIA

Abstract

Background:Although chemotherapeutic(CT) agents that used in the treatment of acute lymphoblastic leukemia(ALL) increase survival, the results are still weak. Long‐term survival with CT's in relapse ALL cases is difficult and the prognosis is very weak. Inotuzumab ozogamicin is an anti‐CD 22 monoclonal antibody and it has the potential to reduce the overall toxicity of intensive regimens for ALL, as well as to possibly increase the number of patients who may achieve a state of minimal residual disease.Aims:We aimed to present a case of successful haploidentic bone marrow transplantation in a recurrent B‐ALL patient who was in remission with inotuzumab ozogamicin.Methods:Case description: 26‐year‐old male patient was diagnosed with B‐cell ALL in December 2017. After the HOELZER CT protocol was started, maintenance treatment was continued.In the fifth month of treatment,FLAG CT protocol was started cause of recurrence was seen on 5% blast detection in peripheral blood smear. In August 2018, inotuzumab ozogamicin treatment was started and six cures were completed because the patient was not in remission. In September 2018, He had gone Haploidentical bone marrow transplantation from his sibling donor(8/10) with Defibrotid prophylaxis for Veno‐Occlusive Disease(VOD)s. He engrafted succesfully and chimerizm was 99.85% in 30th days of transplantation. He is 60th day of transplantation and in a remission.Results:Bone marrow transplantation cannot be performed since the complete response cannot be achieved in patients with relapse and resistant B‐ALL. In these patients, new therapies targeting malignant lymphoblasts are needed. Inotuzumab ozogamicinis a monoclonal antibody drug conjugate that targets CD22 antigen on malignant lymphoblasts.In many studies, it has been shown that Inotuzumab ozogamycin is effective and reliable anti‐tumor activity in adults with recurrent and resistant CD22 positive ALL. However, monoclonal antibody drug conjugates have been shown to be associated with VOD's. For this purpose, we used Defibrotid to protect our patient from VOD.Summary/Conclusion:Treatment with combination CT regimens in B‐ALL is suboptimal and long‐term survival is achieved in only 30‐40% of patients. Targeted molecular therapy and new regimens are needed in relapse and resistant patients. At this point, Inotuzumab ozogamycin is an anti‐CD‐22 monoclonal antibody, as in our case, it provides remission in recurrent and resistant B‐ALL patients and allows patients to complete their treatment with an allogeneic transplant from a fully compatible donor.