Pooled Cord Blood Stem Cells Show Promise in Blood Cancer Treatment: Phase 2 Trial Results

A novel approach to umbilical cord blood transplantation has demonstrated promising results in a phase 2 clinical trial, offering new hope for patients with blood cancers who lack a closely matched stem cell donor. The study, published in the Journal of Clinical Oncology on April 27, 2026, found that 96% of participants with leukemias and myelodysplastic syndrome survived at least one year after receiving a combination of traditional cord blood transplant and a pooled stem cell product derived from multiple cord blood units.

High Survival Rates and Reduced Complications

The trial, conducted at Fred Hutch Cancer Center in Seattle, involved 28 patients who received the experimental treatment. Of these, 27 survived for at least 12 months post-transplant, with many now approaching two years of continued positive outcomes. Notably, none of the patients developed severe acute or chronic graft-versus-host disease (GVHD), a common and potentially life-threatening complication of stem cell transplantation.

Graft-versus-host disease occurs when donated stem cells attack the recipient’s body, leading to severe inflammation and organ damage. The absence of severe GVHD in this trial suggests that the pooled stem cell approach may improve safety compared to traditional methods, where GVHD remains a significant risk.

How the Pooled Stem Cell Product Works

The innovative treatment combines a standard cord blood transplant with dilanubicel, a stem cell product created by pooling cells from six to eight different cord blood units. This pooling increases the total number of stem cells available for transplantation, addressing a key limitation of single-unit cord blood transplants: the often insufficient cell count for adult patients.

Filippo Milano, MD, PhD, the study’s principal investigator and director of the Cord Blood Program at Fred Hutch Cancer Center, described the approach as groundbreaking. “This is the first time transplant patients received cells from what amounts to nine different human beings,” he said. Milano, who also holds the Endowed Chair of Cord Blood Research at Fred Hutch, emphasized the potential of this method to expand access to life-saving transplants, particularly for multiethnic patients who struggle to find closely matched donors.

Addressing a Critical Gap in Stem Cell Transplantation

Stem cell transplantation is a standard treatment for blood cancers such as leukemia and myelodysplastic syndrome, as well as other blood disorders. However, finding a suitable donor can be challenging, especially for patients from diverse ethnic backgrounds. Traditional donor registries often lack sufficient matches for non-white patients, leaving many without viable treatment options.

Cord blood stem cells offer a solution because they do not require as stringent a match as adult donor cells. However, the limited number of cells in a single cord blood unit has historically restricted their use, particularly in adult patients. The pooled stem cell approach overcomes this limitation by combining multiple units, providing a larger and more effective dose of stem cells.

Milano expressed gratitude for the participation of patients and the clinical care team, noting their role in advancing the field. “I am grateful for the boldness and courage from our patients and clinical care team to move the transplant field forward with this new approach,” he said.

Implications for Future Treatment

The trial’s results suggest that the pooled stem cell method could make cord blood transplantation more accessible and effective for a broader range of patients. While the findings are promising, further research is needed to confirm the long-term safety and efficacy of the approach. Larger phase 3 trials will be essential to validate these results and determine whether the method can become a standard treatment option.

For now, the study represents a significant step forward in addressing the challenges of stem cell transplantation, particularly for patients who lack a closely matched donor. The absence of severe GVHD and the high survival rate observed in the trial provide a strong foundation for future research and potential clinical adoption.

What’s Next for the Research?

The research team at Fred Hutch Cancer Center plans to continue monitoring the trial participants to assess long-term outcomes, including survival rates beyond two years and the durability of the treatment’s benefits. Efforts are underway to explore the potential of the pooled stem cell approach in treating other blood disorders and expanding its use to a larger patient population.

As the field of stem cell transplantation evolves, innovations like this pooled stem cell product could play a crucial role in improving patient outcomes and reducing disparities in access to life-saving treatments. For patients with blood cancers and other blood diseases, these advancements offer renewed hope for effective and accessible care.