BPX-501: Positive Data in Haploidentical Hematopoietic Stem Cell Transplantation

Lead product candidate designed to improve outcomes and broaden eligibility to many more patients who lack a family matched donor

Much has been accomplished with our lead product candidate BPX-501, an adjunct T-cell therapy being evaluated initially in children with leukemias, lymphomas and genetic blood diseases undergoing T-depleted, haploidentical hematopoietic stem cell transplantation (HSCT), with encouraging results. BPX-501, with its CaspaCIDe® safety switch, addresses physicians’ reluctance to perform a haploidentical (partial match) transplant, which has a higher risk of life-threatening infections and Graft versus Host Disease (GvHD) than standard-of-care transplants from a fully matched donor. Unlike a matched donor, a haploidentical donor, typically a parent, is almost always available.

Haploidentical transplants are often T-cell depleted in order to reduce the risk of GvHD. But a lack of donor T cells leads to increased rates of deadly infections in the transplanted patient. Adding BPX-501 T cells to the transplant has resulted in reduced rates of infection, shorter hospital stays, and better overall outcomes. Should uncontrolled GvHD occur, the administration of our proprietary activator drug rimiducid triggers the switch incorporated in the BPX-501 cells, eliminating the T cells that have become toxic.

Updated results from our ongoing Phase 1/2 BP-004 trial, presented at the 2016 annual meeting of the American Society of Hematology (ASH) in December, demonstrated disease-free outcomes for children with inherited immune and blood disorders, including hemoglobinopathies such as Beta Thalassemia Major (β0β0), Sickle Cell Disease and Diamond-Blackfan Anemia; Primary Immune Deficiencies such as Severe Combined Immune Deficiency (“Bubble boy” disease) and Wiskott-Aldrich syndrome; leukemias and lymphomas; and bone marrow failure syndromes. The data showed significantly faster immune recoveries compared to historical control subjects given the same T-depleted, haploidentical transplant but without the BPX-501 add-back, as well as reduced viral infections and reactivation, and reductions in time to hospital discharge and re-hospitalizations due to infection. In five cases where uncontrolled acute GvHD was attributable to BPX-501 cells, rimiducid was administered and symptoms resolved. These results were consistent with previously reported data.

We believe results to date continue to demonstrate BPX-501’s potential to enable critical immune support and improve outcomes in patients undergoing T-depleted haplo-HSCTs. The product candidate represents a potentially vital option for the many patients who are not treated because they lack a perfect match donor.

The European Commission (EC) granted orphan drug designations for BPX-501 for treatment in HSCT, and for activator agent rimiducid for the treatment of GvHD. BPX-501 and rimiducid also has orphan drug status from the U.S. Food and Drug Administration (FDA) as a combination therapy.