Discussion
bleeding, BM failure disorders, febrile neutropenia, thrombocytopenic, malignancy, cytopenia
BLEEDING, RECURRENCE, FEBRILE NEUTROPENIA, EVENT, DISEASE, INJECTION SITE REACTIONS, CYTOPENIA, EVENTS
PGF is an unmet medical need, associated with increased mortality post-HCT [The current standard of care for PGF includes repeated blood product transfusions and HGF. An additional alternative is CD34+ cell boost, which shows encouraging results, but is limited by donor availability, the need to mobilize, extract, and isolate donor cells, and some risk of GvHD associated with the presence of CD3+ cells. In a meta-analysis of 7 retrospective studies reporting CD34+ cell boost for PGF [Outcomes from studies using TPO RA range from 45% to 75% ORR with a 60% 12-month overall survival [Time to peripheral blood count recovery post-HCT depends on many factors, and ranges from 2 to 24 months [Our study demonstrated an acceptable safety profile of PLX-R18 in all tested doses. Injection site reactions were not serious and resolved spontaneously. The observed serious TEAEs of febrile neutropenia (3 events, 1 considered related) and malignancy recurrence (1 event) are within expected rates in this patient population [Study limitations include a small sample size, especially for lower doses; lack of a control arm, limiting the ability to rule out spontaneous recovery as an explanation for the results; and a heterogeneous population on several parameters, such as onset PGF post-HCT, underlying disease, HCT cell source, and baseline blood counts. These limitations make the interpretation of the results challenging. However, both HR and survival rates observed in our study mirror rates reported in the literature [The IM route of administration may also be considered a limitation due to the discomfort and potential for bleeding in thrombocytopenic patients. As is observed for MSCs in the post-HCT setting [The results of our study are encouraging and indicate a potential role for PLX-R18 in accelerating hematopoietic recovery post-HCT. Additional studies are warranted to optimize the efficacy of PLX-R18 in the treatment of PGF and to expand the potential to other BM failure disorders and cytopenia associated with certain treatment modalities such as CAR-T therapy.