Once discarded as medical waste, cord blood is now recognized as a valuable source of stem cells that is simple to collect and store, rapidly available and is less likely to promote an immune response. Perhaps most significantly, cord blood transplant has historically not required a perfect HLA match due to the relative immaturity of the cells, though research has shown that a higher HLA match results in better overall survival for patients. More than 25,000 patients around the world facing diseases like leukemia, lymphoma and sickle cell anemia have been given a second chance at life thanks to cord blood units.
As the overall demand for stem cells has increased in recent years, the demand for cord blood has actually declined since 2010. With more than 249,000 available units listed on the Be The Match Registry®, cord blood is readily available for transplant centers and biotherapies companies—so why aren’t they taking advantage?
This decline is thought to be the result of an increase in haploidentical transplants but may also have something to do with another factor: size of the units. Cord blood units are small and thus contain a smaller number of stem cells when compared to other sources.
“The number of cells obtained is often not enough for an adult patient. To give you perspective, they’re stored in a bag that’s the size of your hand,” said Merry Duffy, Director of Cord Blood Operations at the National Marrow Donor Program®/Be The Match®. “This is the major disadvantage of cord blood and why so many companies are trying to do research into expanding those cells.”
Companies such as Gamida Cell, Nohla Therapeutics and Magenta Therapeutics are developing expansion techniques to take advantage of this under-utilized resource. Expanded umbilical cord blood units have increased cell dose and result in faster engraftment—suggesting strong potential for commercial cord blood products in the near future.
“These expansion protocols are very promising,” said Abby McDonald, PhD, Senior Business Lead, Product Development Operations at Be The Match BioTherapies. “We can potentially increase the number of patients for whom cord blood transplant would be an option. Clinical trials that are investigating the use of cord blood transplants into non-traditional transplant indications, such as ischemic stroke, are also very exciting. If cord blood transplants can be used to treat some of those non-traditional indications, it would mean a lot for not only the industry but for patients all over the world.”