Approximately 25,000 allogeneic hematopoietic cell transplants (bone marrow, peripheral blood, or cord blood transplants - BMT) are performed annually worldwide. According to data from the National Marrow Donor Program (NMDP) alone, more than 6000 men, women and children are searching the NMDP registry on any given day to find a match for a stem cell transplant. A large number of these searches do not find matches as the stringency of matching criteria is very high.

These patients increasingly rely on cord blood as a source of stem cells owing to the fact that chances of finding a match with cord blood is up to 18 times higher than from an alternate source. But the limited quantity of stem cells in the cord blood that restrict its utility to pediatric patients (age 18 or lower) wherein cord blood contributes as a source of stem cells for >50% of the transplants performed. However <20% of the total transplants in adults (age 18 or older) are now utilizing cord blood as per data from NMDP. Japan is a notable exception however with >50% of the transplants performed employ cord blood (probably owing to lower body weight of patients).

To allow for multiple uses and also to increase their capacity for transplantation in adolescents and adults, researchers are developing methods to stimulate stem cells to divide and increase in number while retaining their primitive state. This process is known as stem cell expansion. Stem cell expansion is an important tool both for improving transplant outcomes and enabling individuals to use their own cord blood samples for more than one treatment. This is particularly important given advances in regenerative medicine - the science of using the body’s own cells to repair or replace damaged tissues and organs – which will likely increase the number of diseases that cord blood stem cells are able to treat as a result.

Expanding the volume of stem cells available in a cord blood unit would allow even more patients to be treated, including adults. It would also allow those families who have privately banked their cord blood stem cells to use them for multiple treatments and even potentially donate a portion of their cord blood stem cells to use them for multiple treatments and even potentially donate a portion of their cord blood sample to patients in need.

Leading Researchers are Evaluating Expanded Cord Blood Stem Cells in Human Patients

While expanded stem cells are not yet approved for medical use in humans, several expansion studies and clinical trials are underway. Showcased below are three clinical studies that have shown positive results: 1. In a study published in the January 2010 edition of Nature Medicine Scientists at Fred Hutchinson Cancer Research Center described a method that resulted in an average 164-fold increase in count of stem cell, which infused into patients resulted in successful and rapid engraftment. This 10-patient trial demonstrated the feasibility and safety of using expanded cord blood stem cells to treat patients with high-risk malignancies.

2. Investigators at MD Anderson Cancer Center in December 2010 showcased data of a 32-patient study wherein Mesenchymal stem cells were used to expand the number of Hematopoietic stem cells, which resulted in an average 40-fold expansion. On transplantation this led to fast engraftment of neutrophils and platelets, and high-rates of platelet transfusion independence. Recently in July 2011, the USFDA has allowed the progress of this promising technology in phase III clinical trials.

3. The Gamida Cell-Teva Joint Venture (JV) program is the most advanced with already 70 patients enrolled in the pivotal registration, Phase III clinical trial. They expect to complete the enrollment in 100 patients in the Stem Ex study in Q4 2011, and submit a Biologic License Application to the FDA in 2012 as well as a Marketing Authorization Application to the EMA thereafter. A first market launch is planned for the year 2013.

The above studies suggest that expansion technologies may be available to more patients in the future, especially adults, and would significantly help in treating more diseases.