Gamida Advised To Conduct Additional Phase III StemEx Trial
While a current single-arm Phase II/III study provides evidence of activity of StemEx as an alternative transplantation treatment for patients with high-risk leukaemia and lymphoma, the FDA has advised Gamida Cell to conduct another trial: a Phase III, randomised, controlled study. StemEx is in development for patients who could not find a family-related matched bone marrow donor. The data and analysis of the Phase II/III, multicentre, multi-national, historical cohort-controlled study of StemEx were reported by Espicom in April.
Of note, study data showed that the increased dose of CD34+ stem and progenitor cells provided by StemEx was directly associated with a shorter time to neutrophil and platelet engraftment, which in turn, was associated with improved survival at 100 days post-transplantation. Therefore, the clinical outcomes from the Phase II/III study clearly demonstrated a proof-of-concept of StemEx' mode of action. However, the survival advantage was not statistically significant by day 180 with mortality of 32.7 per cent in the StemEx group and 34.7 per cent in the control group (p=0.39). Additionally, StemEx did not create a significant difference in the level of Grade III to IV acute graft versus host disease; 19.4 per cent in the StemEx group and 16.9 per cent in the control group (p=0.11).
StemEx is a graft of an expanded population of stem/progenitor cells, derived from part of a single unit of umbilical cord blood and transplanted by intravenous infusion along with the remaining, non-manipulated cells from the same unit. However, there are a limited number of stem/progenitor cells in cord blood, enabling a quantity sufficient generally only for paediatric treatment. StemEx employs a technology that expands this small number of cord blood stem/progenitor cells, increasing their therapeutic capacity for transplantation in adolescents and adults.