SRSF2 P95L

The discovery of clonal hematopoiesis in this elderly woman with a wide spectrum of severe auto-inflammatory conditions supports a potentially intriguing link between somatic blood mutations and her adult- onset rheumatologic disorders. Mechanistically, disrupted SRSF2-mediated splicing may be driving aberrant antigen presentation by bone marrow-derived dendritic cells in her skin and other organs. Causal relationships between somatic blood mutations and autoimmune/auto-inflammatory conditions have been established in patients with hematologic malignancies and conditions like VEXAS syndrome.

Three patients were treated with thrombopoietin receptor agonists (2 eltrombopag, 1 romiplostim) and had minimal transient platelet count increases not meeting the IWG MDS criteria for response. Three patients have received allogeneic hematopoietic stem cell transplant.Conclusion :This series describes a subset of CCUS patients with isolated thrombocytopenia associated with SRSF2 mutations. We also describe atypical megakaryocytic findings which do not meet current WHO diagnostic criteria for dysmegakaryopoiesis; however, the uniform presence of these findings in this cohort suggests an association with thrombocytopenia and CCUS.

Luxeptinib simultaneously suppresses additional signaling pathways in AML cells (CSF1R, PDGFRα, TRK, SYK, BTK, LYN, AKT, ERK, MAPK), kills primary AML cells insensitive to other FLT3 inhibitors at pM and low nM concentrations, and shows enhanced activity in combination with venetoclax...One heavily pretreated AML patient (8 prior regimens including alloSCT and FLT3 inhibitors gilteritinib and crenolanib) had 99% reduction of blasts in peripheral blood (from 6.38x10 3 /µL at C1D1 to 0.09x10 3 /µL at C1D15), though the decrease in blasts reversed during Cycle 2...MRD-negative complete remission (CR) was confirmed in one FLT3-ITD AML patient (6 prior regimens including 2 alloSCT and FLT3 inhibitor sorafenib) at Cycle 5 of treatment evidenced by reduction of FLT3-ITD VAF and blasts in bone marrow to below limit of detection (LOD) of PCR-based FLT3-ITD assay and high-sensitivity flow cytometry (LOD < 0.1%), respectively... As of June 7, 2021, luxeptinib is well tolerated at dose levels of 450 and 600 mg BID over multiple cycles and escalated to 750 mg BID (Cohort 3). Pharmacodynamic studies documented inhibition of FLT3 signaling, and anti-leukemic activity has been observed in heavily pretreated relapsed FLT3-ITD AML patients as evidenced by significant reduction of FLT3-ITD VAF and blasts in bone marrow and / or peripheral blood. One FLT3-ITD AML patient has had confirmed MRD negative CR and continues treatment.