Salvage haploidentical transplantation for graft failure after first haploidentical allogeneic stem cell transplantation: an updated experience.

Graft failure is a fatal complication following allogeneic stem cell transplantation where a second transplantation is usually required for salvage. However, there are no recommended regimens for second transplantations for graft failure, especially in the haploidentical transplant setting. We recently reported encouraging outcomes using a novel method (haploidentical transplantation from a different donor after conditioning with fludarabine and cyclophosphamide). Herein, we report updated outcomes in 30 patients using this method. The median time of the second transplantation was 96.5 (33-215) days after the first transplantation. Except for one patient who died at +19d and before engraftment, neutrophil engraftments were achieved in all patients at 11 (8-24) days, while platelet engraftments were achieved in 22 (75.8%) patients at 17.5 (9-140) days. The 1-year OS and DFS were 60% and 53.3%, and CIR and TRM was 6.7% and 33.3%, respectively. Compared with the historical group, neutrophil engraftment (100% versus 58.5%, p < 0.001) and platelet engraftment (75.8% versus 32.3%, p < 0.001) were better in the novel regimen group, and OS was also improved (60.0% versus 26.4%, p = 0.011). In conclusion, salvage haploidentical transplantation from a different donor using the novel regimen represents a promising option to rescue patients with graft failure after the first haploidentical transplantation.

Mesenchymal stromal cells plus basiliximab improve the response of steroid-refractory acute graft-versus-host disease as a second-line therapy: a multicentre, randomized, controlled trial.

BACKGROUND: For patients with steroid-refractory acute graft-versus-host disease (SR-aGVHD), effective second-line regimens are urgently needed. Mesenchymal stromal cells (MSCs) have been used as salvage regimens for SR-aGVHD in the past. However, clinical trials and an overall understanding of the molecular mechanisms of MSCs combined with basiliximab for SR-aGVHD are limited, especially in haploidentical haemopoietic stem cell transplantation (HID HSCT). METHODS: The primary endpoint of this multicentre, randomized, controlled trial was the 4-week complete response (CR) rate of SR-aGVHD. A total of 130 patients with SR-aGVHD were assigned in a 1:1 randomization schedule to the MSC group (receiving basiliximab plus MSCs) or control group (receiving basiliximab alone) (NCT04738981). RESULTS: Most enrolled patients (96.2%) received HID HSCT. The 4-week CR rate of SR-aGVHD in the MSC group was obviously better than that in the control group (83.1% vs. 55.4%, P = 0.001). However, for the overall response rates at week 4, the two groups were comparable. More patients in the control group used ≥ 6 doses of basiliximab (4.6% vs. 20%, P = 0.008). We collected blood samples from 19 consecutive patients and evaluated MSC-derived immunosuppressive cytokines, including HO1, GAL1, GAL9, TNFIA6, PGE2, PDL1, TGF-ß and HGF. Compared to the levels before MSC infusion, the HO1 (P = 0.0072) and TGF-ß (P = 0.0243) levels increased significantly 1 day after MSC infusion. At 7 days after MSC infusion, the levels of HO1, GAL1, TNFIA6 and TGF-ß tended to increase; however, the differences were not statistically significant. Although the 52-week cumulative incidence of cGVHD in the MSC group was comparable to that in the control group, fewer patients in the MSC group developed cGVHD involving ≥3 organs (14.3% vs. 43.6%, P = 0.006). MSCs were well tolerated, no infusion-related adverse events (AEs) occurred and other AEs were also comparable between the two groups. However, patients with malignant haematological diseases in the MSC group had a higher 52-week disease-free survival rate than those in the control group (84.8% vs. 65.9%, P = 0.031). CONCLUSIONS: For SR-aGVHD after allo-HSCT, especially HID HSCT, the combination of MSCs and basiliximab as the second-line therapy led to significantly better 4-week CR rates than basiliximab alone. The addition of MSCs not only did not increase toxicity but also provided a survival benefit.

FLT3-ITD Allelic Ratio and NPM1 Mutation Do Not Impact Outcomes in Acute Myeloid Leukemia Patients with FLT3-ITD after Allogeneic Hematopoietic Stem Cell Transplantation: A Retrospective Propensity Score- Matching Study.

FLT3-ITD mutation has consistently been correlated with poor outcomes in patients with acute myeloid leukemia (AML). Allogeneic hematopoietic stem cell transplantation (allo-HSCT) plays a major role in curing blood diseases. Whether allo-HSCT can eliminate the detrimental effects of FLT3-ITD mutation in AML patients remains debatable. In addition, studies have shown that the FLT3-ITD allelic ratio (AR) and NPM1 mutation appear to further influence the prognostic utility of FLT3-ITD in patients with FLT3-ITD-mutated AML. The influence of NPM1 mutation and AR on FLT3-ITDmut patients in our database remains unclear. We aimed to compare survival outcomes following allo-HSCT between patients with FLT3-ITDmut and those with wild-type FLT3-ITD and to further analyze the influence of NPM1 and AR on outcomes. A total of 118 FLT3-ITDmut patients and 497 FLT3-ITDwt patients who underwent allo-HSCT were propensity score-matched 1:3 using nearest-neighbor matching with a caliper size of .2. The study cohort comprised 430 patients with AML, including 116 with FLT3-ITDmut and 314 with FLT3-ITDwt. Overall survival (OS) and leukemia-free survival (LFS) were similar in the FLT3-ITDmut patients and the FLT3-ITDwt patients (2-year OS,78.5% versus 82.6% [P = .374]; 2-year LFS, 75.1% versus 80.8% [P = .215]). A cutoff of .50 was applied to define subgroups with low and high FLT3-ITD AR. No significant differences in the cumulative incidence of relapse (CIR) or LFS were observed between the low AR and high AR groups (2-year CIR, P = .617; 2-year LFS, P = .563). CIR and LFS also were comparable when patients were grouped according to the presence or absence of NPM1 and FLT3-ITD (2-year CIR, P = .356; 2-year LFS, P = .159). Additionally, the CIR and LFS of FLT3-ITDmut and FLT3-ITDwt patients tended to differ after matched sibling donor HSCT (2-year CIR, P = .072; 2-year LFS, P = .084); however, these differences were not seen in recipients of haploidentical (haplo-) HSCT (2-year CIR, P = .59; 2-year LFS, P = .794). The presence of minimal residual disease before transplantation and lack of first complete response were identified as risk factors related to inferior outcomes in a multivariate analysis regardless of FLT3-ITD or NPM1 status. Our results suggest that allo-HSCT, especially haplo-HSCT, may overcome the adverse effect of FLT3-ITD mutation irrespective of NPM1 status or AR. Allo-HSCT could be an ideal option for AML patients with FLT3-ITD.

Avapritinib is effective for treatment of minimal residual disease in acute myeloid leukemia with t (8;21) and kit mutation failing to immunotherapy after allogeneic hematopoietic stem cell transplantation.

In patients with t(8;21) acute myeloid leukemia (AML) with recurrent measurable residual disease (MRD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT), pre-emptive interferon-α therapy and donor lymphocyte infusion are noneffective in 30%-50% of patients. Avapritinib is a novel tyrosine kinase inhibitor targeting KIT mutations. We retrospectively report about 20 patients with t(8;21) AML and KIT mutations treated with avapritinib after allo-HSCT with MRD and most failing to respond to immunotherapy. Reduction of RUNX1-RUNX1T1 after 1 month of treatment was ≥1 log in 12 patients (60%), which became negative in 4 patients (20%). In 13 patients who received avapritinib for ≥3 months, the reduction was ≥1 log in all patients, which became negative in 7 patients (53.8%). The median follow-up time was 5.5 (2.0-10.0) months from avapritinib initiation to the last follow-up. Three patients underwent hematologic relapse and survived. Among all 20 patients, RUNX1-RUNX1T1 transcripts turned negative in 9 patients (45%). The efficacy did not differ significantly between D816 and non-D816 KIT mutation groups. The main adverse effect was hematological toxicity, which could generally be tolerated. In summary, avapritinib was effective for MRD treatment in patients with t(8;21) AML with KIT mutations failing to respond to immunotherapy after allo-HSCT.

Cytokine profiling during conditioning in haploidentical stem cell transplantation and its prognostic impact on early transplant outcomes.

Cytokine storm development is a major cause of many transplant-related complications, especially during the conditioning regimen. This study aimed to characterize the cytokine profile and determine its prognostic impact during conditioning in patients undergoing subsequent haploidentical stem cell transplantation. A total of 43 patients were enrolled in this study. Sixteen cytokines associated with cytokine release syndrome (CRS) during anti-thymocyte globulin (ATG) treatment were quantified in patients undergoing haploidentical stem cell transplantation. Thirty-six (83.7%) patients developed CRS during ATG treatment; most of those cases (33/36; 91.7%) were classified as grade 1 CRS, whereas only three (7.0%) developed grade 2 CRS. CRS was observed more frequently on the first (15/43; 34.9%) and second day (30/43; 69.8%) of ATG infusion. No factors were identified that could predict the development of CRS on the first day of ATG treatment. Five of the 16 cytokines (interleukins 6, 8, and 10 (IL-6, IL-8, and IL-10), C-reactive protein (CRP), and procalcitonin (PCT)) were significantly elevated during ATG treatment, although only the level of IL-6, IL-10, and PCT were associated with the severity of CRS. However, neither CRS nor the cytokine levels significantly impacted the development of acute graft-versus-host disease (GVHD) or cytomegalovirus (CMV) infection or affected overall survival.

Mutation of the TP53 gene in acute lymphoblastic leukemia does not affect survival outcomes after haploidentical hematopoietic stem cell transplantation.

Previous studies have demonstrated that TP53 mutation is correlated with insufficient therapy response and unfavorable prognosis in acute lymphoblastic leukemia (ALL). Few studies have investigated the impact of TP53 mutation in ALL patients after haploidentical hematopoietic stem cell transplantation (haplo-HSCT). We completed a retrospective study of 65 ALL patients with available TP53 status who underwent haplo-HSCT. They were divided into a TP53 mutation group (TP53mut ) and a TP53 wild-type (TP53wt ) group. TP53mut showed comparable 2-year cumulative incidence of relapse (CIR) rates (13.1% vs 12.5%, P = .96) and 2-year leukemia-free survival (LFS) (74.2% vs 77.4%, P = .80) with TP53wt . No significant differences in 2-year overall survival (OS) rates (82.9% vs 87.3%, P = .61) or 2-year NRM rates (12.7% vs 10.2%, P = .69) were observed in TP53mut and TP53wt patients. Multivariate analysis suggested that white blood cell (WBC) count at initial diagnosis (>50 × 109 /L: hazard ratio [HR] = 3.860, P = .016) and age (>40 years old: HR = 4.120, P = .012) are independent risk factors for 2-year LFS. Our study showed that TP53 mutations may not be related to the unfavorable impact on survival in ALL patients after treatment with haplo-HSCT. The present results suggested that haplo-HSCT may eliminate the poor prognosis effect of TP53 mutation in ALL.

Haploidentical- versus identical-sibling transplant for high-risk pediatric AML: A multi-center study.

BACKGROUND: Human leukocyte antigen-identical sibling donor (ISD)-hematopoietic stem cell transplantation (SCT) is a potentially curative treatment for high-risk pediatric acute myeloid leukemia (AML). A haploidentical donor (HID) is readily available to almost all children. Previous studies have demonstrated that patients with HID-SCT had similar outcomes compared to ISD-SCT for pediatric and adult AML. However, the role of HID-SCT in high-risk pediatric AML is unclear. METHODS: To compare the overall survival of high-risk AML children who underwent either HID-SCT or ISD-SCT, we analyzed 179 cases of high-risk AML patients under 18 years of age treated with either ISD-SCT (n = 23) or HID-SCT (n = 156). Granulocyte colony-stimulating factor plus anti-thymocyte globulin-based regimens were used for HID-SCT. We also analyzed the subgroup data of AML patients at first complete remission (CR1) before SCT with known cytogenetic risk. RESULTS: The numbers of adverse cytogenetic risk recipients were 8 (34.8%) and 13 (18.8%) in the ISD-SCT group and the HID-SCT group, and the number of patients with disease status beyond CR1 were 6 (26.1%) and 14 (20.3%) in the two groups. The cumulative rates of grades II-IV acute graft-versus-host disease (GVHD) were 13.0% in the ISD-SCT group and 34.8% in the HID-SCT group (P = 0.062), with a three-year cumulative rates of chronic GVHD at 14.1% and 34.9%, respectively (P = 0.091). The relapse rate in the ISD-SCT group was significantly higher than that in the HID-SCT group (39.1% vs. 16.4%, P = 0.027); with non-relapse mortality at 0.0% and 10.6% (P = 0.113), respectively. The three-year overall survival rates were 73.0% for the ISD-SCT group and 74.6% for the HID-SCT group (P = 0.689). In subgroup analysis, the three-year relapse rate in the ISD-SCT group was higher than that in the HID-SCT group (50.0% vs. 9.2%, P = 0.001) and the three-year DFS in the ISD-SCT group (50.0%) was lower than that in the HID-SCT group (81.2%) (P = 0.021). CONCLUSIONS: Unmanipulated HID-SCT achieved DFS and OS outcomes comparable to those of ISD-SCT for high-risk pediatric AML patients with potentially higher rate but manageable GVHD.