Published on February 19, 2026
Umbilical Cord Blood Transplantation in the PTCy Era: Integrating Emerging Expansion Platforms With Contemporary Donor-Selection Guidelines
by Alex Khadhim
Two recent letters in Transplantation and Cellular Therapy debate how umbilical cord blood (UCB) should be positioned in modern donor-selection guidance now that post-transplant cyclophosphamide (PTCy) has expanded access to alternative adult donors. Das et al., writing from University Hospitals Cleveland Medical Center, Case Western Reserve University, and the University of Illinois Chicago, argue that the 2025 NMDP/CIBMTR recommendations understate UCB’s current value because they are shaped by historical outcomes with unmanipulated units and older GVHD prophylaxis approaches. In response, Schaffer et al., writing from centers including Memorial Sloan Kettering Cancer Center alongside investigators involved in NMDP/CIBMTR guideline efforts, the Medical College of Wisconsin, and the University of Miami, agree that UCB remains important but emphasize that guideline rankings should be driven by broadly validated survival outcomes and what is feasible across most transplant programs.
Das et al. highlight that UCB retains practical advantages, particularly rapid availability, tolerance of HLA mismatch, and historically low chronic GVHD, which can be decisive when time is limited or when finding a well-matched unrelated donor is difficult. They contend that the evidence base is changing because modern UCB expansion platforms have improved engraftment kinetics and may reduce early complications, which could materially shift risk–benefit comparisons versus other graft sources. They also emphasize access and equity, noting that registry match likelihoods are lower for patients from diverse genetic ancestries and proposing that UCB can still expand transplant access. Finally, Das et al. call for clearer, disease-specific guidance, especially in pediatrics and nonmalignant indications where UCB has traditionally performed strongly.
Schaffer et al. counter that donor-selection guidelines should prioritize endpoints such as overall survival and nonrelapse mortality across broad, real-world practice, and they caution against elevating UCB based on expansion technologies that are not yet widely available, standardized, or proven to improve survival in head-to-head comparisons against adult-donor strategies. They underscore enduring tradeoffs of UCB, including slower hematopoietic recovery in many settings, infection risks, and the inability to obtain additional donor-derived cellular products later (for example, donor lymphocyte infusions). They also argue that PTCy has substantially increased the availability and effectiveness of adult-donor approaches, meaning UCB is less often the only viable option at the population level. At the same time, Schaffer et al. acknowledge that pediatric and nonmalignant indications warrant dedicated donor-selection frameworks and that guideline recommendations should evolve as ongoing trials and approvals for expanded UCB mature.
References:
Das R, Mahmud N. Revisiting Allogeneic Hematopoietic Cell Donor Selection Guidelines: Umbilical Cord Blood in the PTCy Era. Transplant Cell Ther. Published online January 2, 2026. http://doi.org10.1016/j.jtct.2025.12.998
Shaffer BC, Spellman SR, Shaw BE, Jimenez Jimenez AM. Response to "Revisiting Allogeneic Hematopoietic Cell Donor Selection Guidelines: Umbilical Cord Blood in the PTCy Era". Transplant Cell Ther. Published online January 3, 2026. http://doi.org/10.1016/j.jtct.2025.12.997
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