BPX‐501 to improve Immune Recovery and Graft versus Host Disease (GvHD) after Haploidentical Stem Cell Transplant

Haematopoietic stem cell transplantation (HSCT) is the treatment of choice with the intention of cure for some malignant and non‐malignant blood disorders. HSCT involves a patient receiving stem cells (cells that can develop into different types of cells) to help the bone marrow produce healthy blood cells. For many patients who require HSCT, it is often difficult to find a fully matched donor. When the donor is partly matched to the patient (e.g. a close relative), the risk of the patient developing graftversus‐host disease (GvHD) is increased. In order to reduce the risk of GvHD, either the immune cells (T‐cells) need to be removed or a post‐transplant treatment is used to suppress the immune system.
BPX‐501 is a medicinal product made of T‐cells, a type of white blood cell, extracted from a donor who is partly matched to a patient undergoing HSCT. These T‐cells are expected to help the patient to fight off viral infections while their immune system is being restored with the transplanted stem cells. However, the transplanted T‐cells can cause GvHD. BPX‐501 incorporates a safety mechanism where the T‐cells are genetically modified to include a ‘suicide gene’. If the patient develops GvHD, a medicine called rimiducid is given to switch on the suicide gene in the T‐cells. This causes the T cells to die, thus preventing worsening of the GvHD. BPX‐501 has the potential to reduce hospital admissions, infections and improve survival when used in combination with standard care.