AXL and B-cell chronic lymphocytic leukemia: Using a “tartrate salt” formulation of TP-0903 we have examined CLL B-cells isolated over time from patients currently on ibrutinib for relapsed/refractory disease and in a small subset who relapsed on ibrutinib therapy for the impact of TP-0903 on CLL B-cell survival and the expression/activation status of Axl.