European Commission Greenlights UM171 Cell Therapy for Hematologic Malignancies

The European Commission has granted conditional approval to UM171 cell therapy (Zemcelpro) for the treatment of patients with hematologic malignancies who require allogeneic hematopoietic stem cell transplantation (HSCT) after myeloablative conditioning when no other suitable type of donor cells is available.1

In June 2025, UM171 cell therapy earned a positive opinion from the European Medicines Agency’s Committee for Medicinal Products for Human Use.2 Of note, UM171 cell therapy is a novel personalized cryopreserved HSCT product containing UM171-expanded CD34-positive cells (dorocubicel), along with unexpanded CD34-negative cells, each of which is derived from the same core blood unit.1 The approval authorizes the marketing of UM171 cell therapy in all 27 European Union states, as well as Iceland, Norway, and Liechtenstein. Additional regulatory filings are anticipated for UM171 in other countries, including the United States, Canada, the United Kingdom, and Switzerland.

“The curative potential of allogeneic stem cell transplantation is still limited by access to a suitable donor. Access to stem cell donation according to the stringent disease course is one of the major limiting factors for success,” Fabio Ciceri, MD, a professor of hematology at Vita-Salute San Raffaele University in Milan, Italy, stated in a news release. “UM171 cell therapy offers an option timely available for patients in need.”

UM171 has been evaluated in phase 2 trials for the treatment of patients with high- and very high­–risk acute leukemias and myelodysplasias who have limited treatment options, lower survival outcomes, and a high incidence of relapse with current standard of care. Specifically, this includes patients with TP53 mutations and other genetic abnormalities, those who require a second transplant, and those with refractory or active disease.

Notably, 2 independent prospective trials, which included a phase 1/2 study (NCT02668315) and a phase 2 study (NCT04103879), assessed the efficacy and safety of UM171 cell therapy for the treatment of patients with high- and very high–risk acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and myelodysplastic syndrome (MDS).3

Patients included in the studies were required to have adequate organ function and a comorbidity index defined by the transplant center. Once enrolled, patients were treated with a single UM171 7-day expanded and cryopreserved core blood dose after a myeloablative or mid-intensity conditioning regimen.

Among patients treated with UM171 cell therapy (n = 50), at a median follow-up of 24 months (range, 0.7-39), the estimated 2-year overall survival (OS) and progression-free survival (PFS) rates were 67% (95% CI, 54%-82%) and 63% (95% CI, 50%-79%), respectively. Furthermore, the estimated 2-year OS rates for patients with second or third transplants and TP53 mutations were 64% (95% CI, 43%-96%) and 40% (95% CI, 19%-86%), respectively. Moreover, the 2-year cumulative incidence of nonrelapse mortality was 19% (95% CI, 8%-31%), and the incidence of relapse was 18% (95% CI, 6%-29%).

Regarding safety, the incidence of grade 2 to 4 and grade 3 to 4 acute graft-vs-host-disease (GVHD) was 69% (95% CI, 56%-82%) and 16% (95% CI, 6%-27%), respectively. The rate of moderate-to-severe chronic GVHD was 7% (95% CI, 1%-15%), which led to a chronic relapse-free survival rate of 55% (95% CI, 42%-72%).

“This authorization marks a pivotal milestone in delivering on the therapeutic promise of [UM171 cell therapy] for adults battling life-threatening hematologic malignancies,” David Millette, chief executive officer of ExCellThera, the developer of UM171 cell therapy, added in the news release.1 “As the first and only cell therapy approved for patients without access to suitable donor cells, [UM171 cell therapy] offers a vital new stem cell transplant option—and renewed hope—for those who have been left without one.”

References

1. Zemcelpro (UM171 cell therapy) receives EC authorization as the first and only cell therapy for blood cancer patients without access to suitable donor cells. News release. ExCellThera. August 27, 2025. Accessed August 27, 2025. https://www.prnewswire.com/news-releases/zemcelpro-um171-cell-therapy-receives-ec-authorization-as-the-first-and-only-cell-therapy-for-blood-cancer-patients-without-access-to-suitable-donor-cells-302539224.html
2. Zemcelpro (UM171 cell therapy) receives positive CHMP opinion for treatment of blood cancer patients without access to suitable donor cells. News release. ExCellThera. June 19, 2025. Accessed August 26, 2025. https://excellthera.com/news/zemcelpro-um171-cell-therapy-receives-positive-chmp-opinion-for-treatment-of-blood-cancer-patients-without-access-to-suitable-donor-cells/
3. Milano F, Sauvageau G, Thauvette G, et al. Infusion of UM171-expanded cord blood led to excellent survival in patients with high-risk leukemias: results from two independent phase II studies. Blood. 2023; 142(suppl 1):1040. doi:10.1182/blood-2023-187446