Treatment of transplant-associated thrombotic microangiopathy with ravulizumab: experience of n.n. blokhin center for 2 patients

Introduction: Treatments of transplant-associated thrombotic microangiopathy (TA-TMA) in children after the allogeneic hematopoietic stem cell transplantation (aHSCT) still a challenging problem.New approaches required.Methodology: This is a retrospective study analyzing the experience of ravulizumab treatment of refractory TA-TMA in children after aHSCT.We aimed to present the single center experience of safety, tolerability and efficacy of ravulizumab therapy for children with TA-TMA. Results:We present 2 cases of patients with high-risk TA-TMA diagnosed with both laboratory test and clinical assessment.Patient 1: 17 y.o.girl with secondary AML (after Osteosarcoma).Patient 1 received 2 courses of chemotherapy with AML BFM-oriented protocol and aHSCT from matched unrelated donor (MUD), conditioning regimen includes treosulfan, melphalan and fludarabine.IST included ruxolitinib, ATG and abatacept.TA-TMA started at day 60 after aHSCT with elevated LDH levels, thrombocytopenia, proteinuria, high blood pressure and schistocytosis.Ravulizumab infused 3 times in standard ("adult") dose with the effect.No signs of TA-TMA found in patients at day +200.Patient 1 is alive.Patient 2: 17 y.o.girk with Ph-pos.ALL received aHSCT from MUD, conditioning regimen: TBI, fludarabine and etoposide.IST included tacrolimus, ATG and abatacept.