Distinct clinico-biological features in AML patients with low allelic ratio FLT3-ITD: role of allogeneic stem cell transplantation in first remission.

The mutant burden of FLT3-ITD modulates its prognostic impact on patients with acute myeloid leukemia (AML). However, for patients with low allelic ratio (AR) FLT3-ITD (FLT3-ITDlow, AR < 0.5), clinical features, as well as genomic and transcriptomic profiles remain unclear, and evidence supporting allogeneic hematopoietic stem cell transplantation (allo-HSCT) in first complete remission (CR1) remains controversial. This study aimed to elucidate the genomic features, prognosis, and transplantation outcome of FLT3-ITDIow in AML patients with intermediate-risk cytogenetics. FLT3-ITDlow was associated with a negative enrichment of the leukemic stem cell signature, a marked enrichment of the RAS pathway, and with higher frequencies of RAS pathway mutations, different from those with FLT3-ITDhigh. Concurrent CEBPA double mutations were favorable prognostic factors, whereas MLL-PTD, and mutations in splicing factors were unfavorable prognostic factors in FLT3-ITDlow patients. Patients with FLT3-ITDlow had a shorter overall survival (OS) and event-free survival (EFS) than those with FLT3wt. Allo-HSCT in CR1 was associated with a significantly longer OS and EFS compared with postremission chemotherapy in patients with FLT3-ITDlow. In conclusion, FLT3-ITDlow is associated with different mutational and transcriptomic profiles compared with FLT3-ITDhigh. The presence of concomitant poor-risk mutations exert negative prognostic impacts in patients with FLT3-ITDlow, who markedly benefit from allo-HSCT in CR1.

Busulfan-containing conditioning regimens in allogeneic hematopoietic stem cell transplantation for acute lymphoblastic leukemia: A Taiwan observational study.

BACKGROUND: Allogeneic stem cell transplantation (allo-HSCT) is the ultimate cure for acute lymphoblastic leukemia (ALL). AIM: This study was performed to compare the outcomes of ALL patients receiving busulfan (Bu) with cyclophosphamide (Cy)-based or total body irradiation (TBI)-based regimen in a Chinese population. METHODS: We enrolled 224 adult patients with ALL who received allo-HSCT at National Taiwan University Hospital between 1997 and 2016. RESULTS: The median age at transplantation was 33 years. Before allo-HSCT, 75.9% of patients attained first or late complete remission. A total of 141 patients (62.9%) received Bu/Cy-based conditioning, either myeloablative (MA) or reduced-intensity stem cell transplantation (RIST), and 83 patients received a TBI-based regimen (MA-TBI). Patients receiving the MA-Bu regimen had longer relapse-free survival (RFS) than those receiving the MA-TBI regimen (median, 24.1 vs. 6.7 months, p = .044). There was no difference in overall survival (OS, MA-Bu vs. MA-TBI vs. RIST-Bu: 39.4 vs. 28.2 vs. 13.1 months, p = .276), treatment-related mortality (TRM), or incidences of grade 3-4 acute graft-versus-host disease (GvHD). Among patients receiving identical GvHD prophylactic regimens, there was no difference between MA-Bu and MA-TBI groups regarding the incidence of grade 3-4 acute GvHD, grade 2-4, and all-grade chronic GvHD. In subgroup analysis, patients receiving oral busulfan had comparable RFS and OS to the intravenous busulfan group (p = .436 and p = .236, respectively), but a higher TRM (25% vs. 9.8%, p = .016). In the multivariable analysis, disease status before allo-HSCT was the only risk factor impacting RFS and OS. CONCLUSION: In summary, patients receiving Bu/Cy-based or TBI-based regimens as conditioning had similar results in terms of OS, TRM, and acute GvHD, whereas the use of myeloablative Bu/Cy resulted in a better RFS. A Bu-based regimen could be an alternative conditioning choice for patients who are ineligible to receive TBI. Prospective and randomized controlled trials are warranted to validate the long-term outcomes.

Adoptive donor immunity protects against resolved hepatitis B virus reactivation after allogeneic haematopoietic stem cell transplantation in the world's largest retrospective cohort study.

Reactivation of hepatitis B virus (HBV) by reverse seroconversion (HBV-RS) after allogeneic haematopoietic stem cell transplantation (allo-HSCT) can occur in patients with resolved HBV infection (rHBV, defined as negative HBV surface antigen [HBsAg] and positive HBV core antibody), and may cause fatal hepatitis. To explore the risk factors, we retrospectively identified 817 consecutive patients who underwent allo-HSCT from 2005 to 2016 in this largest single centre cohort from National Taiwan Univerisity Hospital. Transplants using donors or recipients positive for HBsAg or HBV DNA were excluded, leaving 445 rHBV patients for analysis. The 3- and 5-year cumulative incidence of HBV-RS after allo-HSCT was 8·7% and 10·5%, respectively, at a median 16 months after allo-HSCT. All had concurrent HBV reactivation. HBV flares developed in 19% of HBV-RS cases, but none experienced hepatic failure. Neither did it impact non-relapse mortality or overall survival. Multivariate analysis revealed that patients with donor lacking hepatitis B surface antibody and extensive chronic graft-versus-host disease (cGVHD) have the highest risk for HBV-RS, with 5-year incidence of 24·2%. In conclusion, adoptive immunity transfer from the donor seems to have protective effects against HBV-RS, which may alter future donor selection algorithms, and combined with extensive cGVHD provides a good target for risk-adaptive HBV prophylaxis.

GATA2 zinc finger 1 mutations are associated with distinct clinico-biological features and outcomes different from GATA2 zinc finger 2 mutations in adult acute myeloid leukemia.

Mutations of the GATA binding protein 2 (GATA2) gene in myeloid malignancies usually cluster in the zinc finger 1 (ZF1) and the ZF2 domains. Mutations in different locations of GATA2 may have distinct impact on clinico-biological features and outcomes in AML patients, but little is known in this aspect. In this study, we explored GATA2 mutations in 693 de novo non-M3 AML patients and identified 44 GATA2 mutations in 43 (6.2%) patients, including 31 in ZF1, 10 in ZF2, and three outside the two domains. Different from GATA2 ZF2 mutations, ZF1 mutations were closely associated with French-American-British (FAB) M1 subtype, CEBPA double mutations (CEBPAdouble-mut), but inversely correlated with FAB M4 subtype, NPM1 mutations, and FLT3-ITD. ZF1-mutated AML patients had a significantly longer overall survival (OS) than GATA2-wild patients and ZF2-mutated patients in total cohort as well as in those with intermediate-risk cytogenetics and normal karyotype. ZF1 mutations also predicted better disease-free survival and a trend of better OS in CEBPAdouble-mut patients. Sequential analysis showed GATA2 mutations could be acquired at relapse. In conclusion, GATA2 ZF1 mutations are associated with distinct clinico-biological features and predict better prognosis, different from ZF2 mutations, in AML patients.

Incorporation of mutations in five genes in the revised International Prognostic Scoring System can improve risk stratification in the patients with myelodysplastic syndrome.

Gene mutations have not yet been included in the 2016 WHO classification and revised International Prognostic Scoring System (IPSS-R), which are now widely utilized to discriminate myelodysplastic syndrome (MDS) patients regarding risk of leukemia evolution and overall survival (OS). In this study, we aimed to investigate whether integration of gene mutations with other risk factors could further improve the stratification of MDS patients. Mutational analyses of 25 genes relevant to myeloid malignancies in 426 primary MDS patients showed that mutations of CBL, IDH2, ASXL1, DNMT3A, and TP53 were independently associated with shorter survival. Patients within each IPSS-R or 2016 WHO classification-defined risk group could be stratified into two risk subgroups based on the mutational status of these five genes; patients with these poor-risk mutations had an OS shorter than others in the same risk group, but similar to those with the next higher risk category. A scoring system incorporating age, IPSS-R and five poor-risk mutations could divide the MDS patients into four risk groups (P < 0.001 for both OS and leukemia-free survival). In conclusion, integration of gene mutations in current IPSS-R improves the prognostication of MDS patients and may help identify high-risk patients for more aggressive treatment in IPSS-R lower risk group.

Reduced incidence of interstitial pneumonitis after allogeneic hematopoietic stem cell transplantation using a modified technique of total body irradiation.

Allogeneic hematopoietic stem cell transplantation is a curative-intent treatment for patients with high-risk hematologic diseases. However, interstitial pneumonitis (IP) and other toxicities remain major concerns after total body irradiation (TBI). We have proposed using linear accelerators with rice-bag compensators for intensity modulation (IM-TBI), as an alternative to the traditional cobalt-60 teletherapy with lung-shielding technique (Co-TBI). Patients who received a TBI-based myeloablative conditioning regimen between 1995 and 2014 were recruited consecutively. Before March 2007, TBI was delivered using Co-TBI (n = 181); afterward, TBI was administered using IM-TBI (n = 126). Forty-four patients developed IP; of these cases, 19 were idiopathic. The IP-related mortality rate was 50% in the total IP cohort and 63% in the idiopathic subgroup. The 1-year cumulative incidences of IP and idiopathic IP were 16.5% and 7.4%, respectively; both rates were significantly higher in the Co-TBI group than in the IM-TBI group. Multivariate analysis revealed that Co-TBI was an independent prognostic factor for both total and idiopathic IP. In the acute myeloid leukemia subgroup, patients with different TBI techniques had similar outcomes for both overall and relapse-free survival. In conclusion, IM-TBI is an easy and effective TBI technique that could substantially reduce the complication rate of IP without compromising treatment efficacy.

Distinct mutation profile and prognostic relevance in patients with hypoplastic myelodysplastic syndromes (h-MDS).

Myelodysplastic syndromes (MDS) are a heterogeneous group of hematologic malignancies. Although most MDS patients have normal or increased BM cellularity (NH-MDS), some have hypocellular BM (h-MDS). The reports concerning the differences in genetic alterations between h-MDS and NH-MDS patients are limited. In this study, 369 MDS patients diagnosed according to the WHO 2008 criteria were recruited. h-MDS patients had lower PB white blood cell and blast counts, and lower BM blast percentages, than those with NH-MDS. h-MDS was closely associated with lower-risk MDS, defined by the International Prognostic Scoring System (IPSS) and revised IPSS (IPSS-R). IPSS-R could properly predict the prognosis in h-MDS (P<0.001) as in NH-MDS patients. The h-MDS patients had lower incidences of RUNX1, ASXL1, DNMT3A, EZH2 and TP53 mutations than NH-MDS patients. The cumulated incidence of acute leukemic transformation at 5 years was 19.3% for h-MDS and 40.4% for NH-MDS patients (P= 0.001). Further, the patients with h-MDS had longer overall survival (OS) than those with NH-MDS (P= 0.001), and BM hypocellularity remains an independent favorable prognostic factor for OS irrespective of age, IPSS-R, and gene mutations. Our findings provide evidence that h-MDS indeed represent a distinct clinico-biological subgroup of MDS and can predict better leukemia-free survival and OS.