Pluristem Therapeutics, Inc., a leading developer of placenta-based cell therapies, has filed the necessary documents requesting that the US Food and Drug Administration (FDA) grant orphan drug status to its PLacental eXpanded (PLX) cells for the treatment of aplastic anaemia.

The filing marks Pluristem’s second orphan drug application to the US FDA. The company applied once before, and successfully received in August of 2011, orphan drug status from the FDA for its PLX cell therapy in the treatment of Buerger’s disease.

Aplastic anaemia is a rare but serious disorder caused by destruction of blood-forming stem cells (Hematopoietic Stem Cells or HSCs) in the bone marrow. While normally HSCs develop into three types of blood cells, red blood cells, white blood cells and platelets, in aplastic anaemia all blood types are deficient, a condition also known as pancytopenia. The disease is considered an emergency situation where patients are supported either with blood transfusions in anticipation of a bone marrow transplant (BMT) or with drugs that suppress the immune system. Aplastic anaemia patients are included in the bone marrow transplant market estimated at $1.3 billion per year in the US alone.

In May of this year, Pluristem announced that a seven year-old girl in Israel, whose condition was rapidly deteriorating due to aplastic bone marrow, experienced a reversal of her condition with a significant increase in her red blood cells, white blood cells and platelets following the intramuscular injection of the company’s PLX cells. Prior bone marrow transplants had failed. The patient has subsequently been released from the hospital and returned home.

"The tremendous recovery exhibited by the paediatric patient afflicted with aplastic anemia who was given our PLX cells under compassionate use has prompted Pluristem to aggressively work towards quickly making our cells available for these patients, a process that will be expedited with the granting of orphan drug status," said Zami Aberman, chairman and CEO of Pluristem. “We are now in the process of establishing an advisory board made up of key opinion leaders in the area of bone marrow transplantation from the United States, Europe and Israel to provide us with valuable insight as we expand our activities in the treatment of the bone marrow diseases and transplantations."

Orphan drug designation qualifies a company for several benefits under the Orphan Drug Act of 1983 (ODA), as amended. These benefits include a seven-year period of orphan drug exclusivity upon product approval, a tax credit for certain clinical testing expenses for the orphan drug, written guidance on the non-clinical and clinical studies needed to obtain marketing approval of an orphan drug, and orphan drug grants.