To assess the in vivo effects of AVID200, Gata1low mice, a murine model of MF, were treated with AVID200 resulting in the reduction in bone marrow (BM) fibrosis and an increase in BM cellularity. AVID200 treatment also increased the frequency and numbers of murine progenitor cells as well as short and long term HSCs.Collectively, these data provide the rationale for TGFβ1 blockade with AVID200 as a therapeutic strategy for MF patients.
Clinical Trial Design: Based on these findings, a phase 1 trial of AVID200 is ongoing in INT-2/high risk MF subjects resistant or intolerant to ruxolitinib; baseline platelet count of ≥ 25 x 109/L, and grade 2/3 BMF. Furthermore, AVID200 therapy improved thrombocytopenia in MF subjects which may be due to AVID200 inhibiting the effects of TGFβ1 on normal MKpoiesis. Updated subject safety and efficacy data along with correlative data will be presented.