Allogeneic Transplantation Yields Long-Term Survival in ALL Population

Allogeneic hematopoietic cell transplantation with myeloablative conditioning improved long-term overall survival (OS) among certain patients with acute lymphoblastic leukemia (ALL), according to 17-year findings from a single-center study presented in a poster session at the 2026 Tandem Meetings.¹

Among 120 adult patients with ALL, treatment yielded a median OS of 10.5 years (95% CI, 3.4-not reached [NR]). The OS rates were 78%, 61%, and 54% at 1, 3, and 5 years, respectively. Additionally, the median OS was 10.5 years among those who received myeloablative conditioning compared with 1.6 years for patients who underwent reduced-intensity or nonmyeloablative (RIC/NMA) regimens (P = .0013).

Data showed a median OS that was NR among patients who were 18 to 39 years old, 10.5 years among those who were 40 to 59 years old, and 1.2 years among those who were 60 to 75 years old (P <.001). Investigators noted that OS outcomes were comparable based on lineage, donor matching, race, and sex.

“OS was superior with myeloablative conditioning and transplantation in first complete remission [CR1], while older age was associated with inferior outcomes. Engraftment was universal and early non-relapse mortality [NRM] was low across conditioning strategies,” lead study author Cristian Taborda, MD, a clinical fellow in Medical Oncology and Hematology at Yale Cancer Center and Yale School of Medicine, wrote with coauthors in the poster.¹ “Within the RIC/NMA group, pentostatin [Nipent] and low-dose total body irradiation [TBI] demonstrated survival comparable to other RIC/NMA regimens over long-term follow-up.”

According to the study authors, allogeneic transplant represents a potentially curative strategy for adult patients with ALL, with post-transplant outcomes often influenced by relapse, NRM, and graft-versus-host disease (GVHD). According to prior literature, the use of hematopoietic cell transplant with RIC yielded a 3-year OS rate of 38% (95% CI, 33%-44%) in a population of patients 55 years and older with B-cell ALL (B-ALL).²

However, survival outcomes may vary depending on different conditioning strategies and patient subgroups. Consequently, investigators sought to assess long-term outcomes among adult patients undergoing allogeneic transplantation for ALL. The study assessed how conditioning intensity and key clinical features may have impacted outcomes across 17 years.

The retrospective single-center analysis took place from 2008 to 2025. Conditioning regimens of interest included myeloablative strategies as well as RIC/NMA platforms using fludarabine- or pentostatin-based treatment with low-dose TBI. Additionally, investigators evaluated calcineurin-inhibitor–based GVHD prophylaxis, and 26% of patients underwent post-transplant cyclophosphamide.

The study’s end points included engraftment, NRM at 100 days, acute and chronic GVHD, and OS. Regarding disease subtypes, patients typically had Philadelphia chromosome (Ph)–negative B-ALL (51%) followed by Ph-positive B-ALL (35%) and T-cell ALL (14%).

The median follow-up was 6 years (95% CI, 5.1-8.0). The median patient age was 43 years (range, 18-75), and 58% of the population were male. Additionally, 70% of patients had CR1 at the time of transplant, and 58% underwent myeloablative conditioning. Regarding donor types, the most common included mismatched unrelated donors (51%), matched related donors (30%), matched unrelated donors (14%), and mismatched related donors (5%).

Study data showed that all patients (100%) underwent engraftment, and the 100-day NRM rate was 7.5%. Grade 2 to 4 instances of acute GVHD occurred in 8.3% of patients, while 39% experienced chronic GVHD. Among 52 patients who died, the most common causes of death included relapse (40%), infections (15%), organ failure (11.5%), and GVHD (2%); 31.5% of patients died due to other causes.

References

1. Taborda C, Isufi I, Bar N, et al. Allogeneic hematopoietic cell transplantation for acute lymphoblastic leukemia: a 17-year single-center experience. Presented at: 2026 Transplantation & Cellular Therapy Meetings of ASTCT and CIBMTR; February 4-7, 2026; Salt Lake City, UT. Abstract 138.
2. Rosko A, Wang HL, de Lima M, et al. Reduced intensity conditioned allograft yields favorable survival for older adults with B-cell acute lymphoblastic leukemia. Am J Hematol. 2017;92(1):42-49. doi:10.1002/ajh.24575