Bellicum Pharmaceuticals, Inc., a clinical stage biopharmaceutical company focused on discovering and developing novel cellular immunotherapies for cancers and orphan inherited blood disorders, announced that the US Food and Drug Administration (FDA) has granted orphan drug designation for BPX-501, the company’s lead product candidate.

The FDA designation is for the combination of BPX-501 genetically modified T cells and activator agent rimiducid as “replacement T-cell therapy for the treatment of immunodeficiency and graft versus host disease (GvHD) after allogeneic hematopoietic stem cell transplant.” BPX-501 is an adjunct T-cell therapy incorporating the Company’s proprietary CaspaCIDe safety switch.

Following an allogeneic transplant, a lack of sufficient mature T cells constitutes immune deficiency that can contribute to infections, viral reactivation, and relapse. The ability to correct this immune deficiency through the add-back of mature donor T cells, without raising the risk of uncontrollable GvHD, has the potential to fundamentally change the risk profile of allogeneic transplantation.

“Expanding the availability of hematopoietic stem cell transplants to more patients with rare genetic diseases and blood cancers is a primary goal of our BPX-501 programme,” commented Tom Farrell, president and CEO of Bellicum Pharmaceuticals. “The FDA’s approval of our request for orphan drug designation is an important milestone that supports our efforts to address key risks and improve outcomes in allogeneic transplant which could make the procedure more viable for patients who lack a perfect match donor.”

BPX-501 is currently being evaluated in multiple phase 1/2 clinical trials in adults and pediatric patients with leukemias, lymphomas, and genetic blood diseases in the US and Europe. Interim results presented at the 2015 ASH Annual Meeting in paediatric patients with a variety of genetic diseases, including beta thalassemia, Wiskott-Aldrich and SCID, demonstrated disease-free outcomes following a haploidentical, T cell-depleted hematopoietic stem cell transplant, followed by an add-back of BPX-501 donor T cells. Results demonstrated reduced infection rates, faster immune reconstitution, and reductions in time to hospital discharge and in re-hospitalisations, compared to historical controls.

The FDA’s Office of Orphan Products Development (OOPD) provides orphan designation to drugs and biologics which are intended for the safe and effective treatment, diagnosis or prevention of rare diseases and disorders that affect fewer than 200,000 people in the US. Orphan designation also qualifies a company for various development incentives, including tax credits for qualified clinical testing and marketing exclusivity for a period of seven years.

BPX-501 is an adjunct T cell therapy of genetically modified donor T cells incorporating Bellicum’s proprietary CaspaCIDe safety switch. The product candidate is designed to provide a safety net to eliminate the BPX-501 alloreactive T cells should severe GvHD occur, enabling physicians to more safely perform haploidentical stem cell transplants by adding back the BPX-501 genetically engineered T cells to speed immune reconstitution and provide control over viral infections.