Cohen S, Roy J, Lachance S, et al. - Whether single UM171(a haematopoietic stem cell self-renewal agonist)-expanded cord blood transplantation affords a safe and effective management option in patients with haematological malignancies who do not have a suitable HLA-matched donor, was investigated in this single-arm, open-label, phase 1–2 study conducted at two hospitals in Canada. This investigation was performed in two parts. Patients aged 3–64 years, weighed 12 kg or more, suffering a haematological malignancy with an indication for allogeneic hematopoietic stem cell transplant, with no suitable HLA-matched donor, and with a Karnofsky performance status score of 70% or more were included in this study. Part 1 involved the administration of two cord blood units (one expanded with UM171 and one unmanipulated cord blood) until UM171-expanded cord blood showed engraftment. Part 2 was commenced once engraftment was reported, and involved the administration of a single UM171-expanded cord blood unit with a dose de-escalation design so that the minimal cord blood unit cell dose that achieved prompt engraftment could be determined. The feasibility, safety as well as the ability of UM171 cord blood stem cell expansion to permit for the employment of small single cords without compromising engraftment was revealed by the preliminary results. Researchers identified 0·52 × 10⁵ CD34-positive cells as the minimal cord blood unit cell dose at thaw that attained prompt engraftment as a single cord transplant following UM171 expansion. By employing UM171-expanded cord blood, the disadvantages of other cord blood transplants might be overcome while maintaining the advantages of low risk of chronic graft-versus-host disease and relapse.