Outcomes of children and young adults with B-cell acute lymphoblastic leukemia given blinatumomab as last consolidation treatment before allogeneic hematopoietic stem cell transplantation.

Blinatumomab has remarkable efficacy in patients with relapsed/refractory (r/r) or measurable residual disease (MRD)-positive B-cell acute lymphoblastic leukemia (B-ALL). In many patients, blinatumomab treatment is followed by allogeneic hematopoietic stem cell transplantation (HSCT). However, the influence of blinatumomab on HSCT outcomes in children and young adults (YA) remains to be fully elucidated. We conducted a single-center, retrospective analysis on patients given blinatumomab as last treatment before HSCT. Seventy-eight pediatric and YA patients were evaluated. With a median follow-up of 23.23 months, the 2-year disease-free (DFS) and overall survival (OS) probability were 72.2% and 89.2%, respectively, with a 2-year cumulative incidence (CI) of non-relapse mortality (NRM) of 2.6%. A trend toward improved 2-year DFS, but not OS, was noted in patients transplanted in first complete remission (CR1) (92.9%) compared to those in second or greater remission (CR2/3) (68.5%, p=0.18) due to a lower CI of relapse (0% vs. 29.9%, p=0.05). Among CR2/3 patients, those receiving the sequential combination of inotuzumab and blinatumomab had a significantly lower CI of relapse as compared to those who did not receive inotuzumab (9.5% vs. 40.4%, p=0.023). Relapse after HSCT occurred in 16 patients, all exhibiting CD19-positive blasts; 10 of them received anti-CD19 chimeric antigen receptor T-cell (CAR-T) therapy and 2 inotuzumab as salvage therapy, leading to a 2-year post-relapse OS of 52.7%. Our results indicate that HSCT following blinatumomab in children and YA with B-ALL is highly effective, being associated with low NRM and not affecting the efficacy of subsequent salvage immunotherapies, including CAR-T cells.

Mucosal-associated invariant T cells are functionally impaired in pediatric and young adult patients following allogeneic hematopoietic stem cell transplantation and their recovery correlates with clinical outcomes.

Mucosal-associated invariant T (MAIT) cells are innate-like T cells implicated in the response to fungal and bacterial infections. Their contribution to restoring T-cell immunity and influencing hematopoietic stem cell transplant (HSCT) outcomes remains poorly understood. We retrospectively studied MAIT-cell recovery in 145 consecutive children and young adults with hematologic malignancies undergoing allogeneic (allo)-HSCT between April 2019 and May 2022, from unrelated matched donor (MUD, N=52), with standard graft-versus-host-disease (GvHD) prophylaxis, or HLA-haploidentical (Haplo, N=93) donor after in vitro αßT/CD19-cell depletion, without post-HSCT pharmacological prophylaxis. With a median follow-up of 33 months (range, 12-49 months), overall survival (OS), disease-free survival (DFS), and non-relapse mortality (NRM) were 79.5%, 72%, and 7%, respectively; GvHD-free relapse-free survival (GRFS) was 63%, while cumulative incidence of relapse was 23%. While αßT cells were reconstituted 1-2 years post HSCT, MAIT cells showed delayed recovery and prolonged functional impairment, characterized by expression of activation (CD25, CD38), exhaustion (PD1, TIM3) and senescence (CD57) markers, and suboptimal ex vivo response. OS, DFS, and NRM were not affected by MAIT cells. Interestingly, higher MAIT cells at day +30 correlated with higher incidence of grade II-IV acute GvHD (19% vs. 7%, P=0.06). Furthermore, a greater MAIT-cell count tended to be associated with a higher incidence of chronic GvHD (cGvHD) (17% vs. 6%, P=0.07) resulting in lower GRFS (55% vs. 73%, P=0.05). Higher MAIT cells also correlated with greater cytomegalovirus (CMV) reactivation and lower late blood stream infections (BSI) (44% vs. 24%, P=0.02 and 9% vs. 18%, P=0.08, respectively). Future studies are needed to confirm the impact of early MAIT-cell recovery on cGvHD, CMV reactivation, and late BSI.

Systematic Review and Meta-Analysis of Health-Related Quality of Life in Patients with ß-Thalassemia that Underwent Hematopoietic Stem Cell Transplantation.

Background: ß-Thalassemia major (ß-TM) represents one of the most important hemoglobinopathies worldwide. Remarkable improvements have been achieved in supportive therapy based on blood transfusions and iron chelation, and nowadays, this approach is capable of assuring a long life in these patients in industrialized countries. The only curative treatment is represented by hematopoietic stem cell transplantation (HSCT). However, this treatment may be burdened by deterioration in the Health-Related Quality of Life (HRQoL). This paper aimed to evaluate the role of HRQoL in transplanted ß-TM patients with a systematic review and meta-analysis. Methods: PubMed database, Web of Science, and Scopus were systematically searched for studies published between January 1st, 2000 to September 2020. The following terms were entered in the database queries: ß-thalassemia, HRQoL, and HSCT. The study was carried out according to the Preferred Reporting Items for Systematic and Meta-analyses (PRISMA) statement. Results: We identified a total of 33 potential studies. Among these, 10 were finally considered in the systematic review and 5 in the meta-analysis. Overall, good scores in the principal domains of HRQoL were reported by transplanted patients. These data were confirmed by results of meta-analysis that showed significant difference between transplanted and ß-TM patients treated with conventional therapy in the physical and emotional dimension, with a medium effect size [d=0.65, 95% CI (0.29-1.02), z = 3.52, p =0.0004, I2=75%; and d=0.59, 95% CI (0.43-0.76), z = 6.99, p <0.00001, I2=0%, respectively]. Conclusion: HRQoL is generally good in ß-TM transplanted patients and may significantly contribute in deciding whether or not to transplant a ß-TM patient treated with conventional therapy.