Post-Transplant Outcomes Studied in Patients With ALL

Patients with acute lymphoblastic leukemia (ALL) who underwent allogeneic hematopoietic stem cell transplantation (HSCT) in their first complete remission (CR) had a two-year overall survival (OS) rate of 73.9%.

Martina Calabrò, MD, of Federico II University of Naples, and colleagues conducted the study to identify risk factors influencing allogeneic HSCT outcomes in patients with ALL who received a transplant between 2015 and 2021. Dr. Calabrò and colleagues presented the results at the 2022 American Society of Hematology Annual Meeting.

The researchers identified 2,349 patients with ALL who received a transplant, including 870 who received a transplant from a matched sibling donor. However, 1,150 of the patients received a transplant from an unrelated donor, with 79% being a 10/10 match and 21% being a 9/10 match. They also identified 329 patients who received a transplant from a haploidentical donor. Peripheral blood was the stem cell source in 85.3% patients. Most patients (79%) received myeloablative conditioning, while the remaining patients received reduced intensity conditioning.

Most patients (56.4%) had Philadelphia chromosome positive B-cell ALL, while 28.4% had Philadelphia chromosome negative B-cell ALL, and 15.2% had T-cell ALL. The median time from diagnosis to transplant was 5.8 months.

The two-year relapse incidence was 22.2%, while the two-year non-relapse mortality rate was 15.4%. The two-year leukemia-free survival rate was 62.3%, while the two-year overall survival (OS) rate was 73.9%.

The cumulative incidence of grade 2-4 acute chronic graft-versus-host disease (GVHD) at 180 days was 29.2%, while the cumulative incidence of grade 3-4 acute GVHD was 10.1% at that time point. At two years, the overall rate of chronic GVHD was 34%, while the rate of extensive chronic GHVD was 15% at that time point. The two-year GVHD-free/relapse-free survival rate was 48%.

Having a matched sibling donor was significantly associated with a lower risk of grade 2-4 acute GVHD compared with having a 9/10 (HR, 0.58; 95% CI, 0.44-0.78; P<.01) or 10/10 matched unrelated donor (HR, 0.70; 95% CI, 0.56-0.87; P<.01).

The use of total body irradiation was significantly associated with a higher risk of grade 2-4 acute GVHD (HR 1.54, 95% CI 1.23-1.92; p<0.01) and chronic GVHD (HR 1.47, 95% CI 1.16-1.87; p<0.01) compared to chemotherapy. However, it was also significantly associated with lower relapse incidence (HR, 0.78, 95% CI 0.61-0.99; P=.04) and higher rates of leukemia-free survival HR=0.80, 95% CI 0.67-0.96; P<.02).

Use of peripheral blood stem cells was independently associated with a higher risk of chronic GVHD, as was the use of a female-donor to male-recipient.

“Use of [total body irradiation] and HLA mismatches are both associated with lower [relapse incidence] despite a higher risk of GVHD, highlighting the importance of tailoring GVHD prophylaxis in these settings,” Dr. Calabrò and colleagues concluded.

Reference

Calabrò M, Labopin M, Battipaglia G, et al. Risk factors influencing transplant outcomes of adults with acute lymphoblastic leukemia in first complete remission: a retrospective analysis from the ALWP of the EBMT. Abstract #2124. Presented at the 64th ASH Annual Meeting and Exposition; December 10-13, 2022; New Orleans, Louisiana.