Prognostic factors in haploidentical transplantation with post-transplant cyclophosphamide for acute myeloid leukemia.

BACKGROUND AIMS: Haploidentical hematopoietic stem cell transplantation (haplo-HCT) is an appropriate option when an HLA-matched related or unrelated donor is not available. Haplo-HCT using post-transplant cyclophosphamide (PTCy) is being increasingly performed worldwide due to its effective suppression of GVHD and its safety. METHODS: We conducted a large nationwide cohort study to retrospectively analyze 366 patients with acute myeloid leukemia undergoing haplo-HCT with PTCy between 2010 and 2019 and to identify prognostic factors. RESULTS: A multivariate Cox analysis revealed that an older recipient age (≥60 years), a male donor to a male recipient, a cytomegalovirus IgG-negative donor to a cytomegalovirus IgG-positive recipient, a poor cytogenetic risk, a noncomplete remission status at the time of transplantation, and a history of HCT were independently associated with worse overall survival (OS). Based on each hazard ratio, these factors were scored (1-2 points) and stratified by their total score into three groups: favorable (0-1 points), intermediate (2-3 points), and poor (4 points or more) groups, and 2-year OS rates were 79.9%, 49.2%, and 25.1%, respectively (P < 0.001). CONCLUSIONS: The present study revealed significant prognostic factors in haplo-HCT with PTCy, and a scoring system based on these factors may be used to predict outcomes.

Chimeric antigen receptor T-cell therapy after COVID-19 in refractory high-grade B-cell lymphoma.

Although chimeric antigen receptor T-cell (CAR-T) therapies have dramatically improved the outcomes of relapsed/refractory B-cell malignancies, recipients suffer from severe humoral immunodeficiencies. Furthermore, patients with coronavirus disease 2019 (COVID-19) have a poor prognosis, as noted in several case reports of recipients who had COVID-19 before the infusion. We report the case of a 70-year-old woman who developed COVID-19 immediately before CAR-T therapy for high-grade B-cell lymphoma. She received Tixagevimab-Cilgavimab chemotherapy and radiation therapy but never achieved remission. She was transferred to our hospital for CAR-T therapy, but developed COVID-19. Her symptoms were mild and she was treated with long-term molnupiravir. On day 28 post-infection, lymphodepleting chemotherapy was restarted after a negative polymerase chain reaction (PCR) test was confirmed. The patient did not experience recurrence of COVID-19 symptoms or severe cytokine release syndrome. Based on the analysis and comparison of the previous reports with this case, we believe that CAR-T therapy should be postponed until a negative PCR test is confirmed. In addition, Tixagevimab-Cilgavimab and long term direct-acting antiviral agent treatment can be effective prophylaxis for severe COVID-19 and shortening the duration of infection.

Collection efficiency and safety of large-volume leukapheresis for the manufacturing of tisagenlecleucel.

BACKGROUND: In patients with relapsed or refractory B cell acute lymphoblastic leukemia or B cell non-Hodgkin lymphoma (r/r B-ALL/B-NHL) with low CD3+ cells in the peripheral blood (PB), sufficient CD3+ cell yield in a single day may not be obtained with normal-volume leukapheresis (NVL). Large-volume leukapheresis (LVL) refers to the processing of more than three times the total blood volume (TBV) in a single session for PB apheresis; however, the efficiency and safety of LVL for manufacturing of tisagenlecleucel (tisa-cel) remain unclear. This study aimed to investigate the tolerability of LVL. STUDY DESIGN AND METHODS: We retrospectively collected data on LVL (≥3-fold TBV) and NVL (<3-fold TBV) performed for patients with r/r B-ALL/B-NHL in our institution during November 2019 and September 2023. All procedures were performed using a continuous mononuclear cell collection (cMNC) protocol with the Spectra Optia. RESULTS: Although pre-apheresis CD3+ cells in the PB were significantly lower in LVL procedures (900 vs. 348/µL, p < .01), all patients could obtain sufficient CD3+ cell yield in a single day with a comparably successful rate of final products (including out-of-specification) between the two groups (97.2% vs. 100.0%, p = 1.00). The incidence and severity of citrate toxicity (no patients with grade ≥ 3) during procedures was not significantly different between the two groups (22.2% vs. 26.1%, p = .43) and no patient discontinued leukapheresis due to any complications. CONCLUSION: LVL procedures using Spectra Optia cMNC protocol was well tolerated and did not affect the manufacturing of tisa-cel.

Impact of Different Fludarabine Doses in the Fludarabine-Based Conditioning Regimen for Unrelated Bone Marrow Transplantation.

The purine analog fludarabine (Flu) plays a central role in reduced-intensity conditioning and myeloablative reduced-toxicity conditioning regimens because of limited nonhematologic toxicities. Few reports assess the impact of different dose of Flu on the clinical outcomes and the Flu doses vary across reports. To compare the effect of Flu dose, the clinical outcomes of patients who received Flu and busulfan (FB; n = 1647) or melphalan (Flu with melphalan (FM); n = 1162) conditioning for unrelated bone marrow transplantation were retrospectively analyzed using Japanese nationwide registry data. In the FB group, high-dose Flu (180 mg/m2; HFB) and low-dose Flu (150/125 mg/m2; LFB) were given to 1334 and 313 patients, respectively. The 3-year overall survival (OS) rates were significantly higher in the HFB group than in the LFB group (49.5% versus 39.2%, P < .001). In the HFB and LFB groups, the cumulative incidences were 30.4% and 36.6% (P = .058) for 3-year relapse and 25.1% and 28.1% (P = .24) for 3-year nonrelapse mortality (NRM), respectively. In the multivariate analysis for OS and relapse, Flu dose was identified as an independent prognostic factor (hazard ratio: 0.83, P = .03; hazard ratio: 0.80, P = .043). In the FM group, high-dose Flu (180 mg/m2; HFM) and low-dose Flu (150/125 mg/m2; LFM) were given to 118 and 1044 patients, respectively. The OS, relapse, and NRM after 3 years did not differ significantly between the HFM and LFM groups (48.3% versus 48.8%, P = .92; 23.7% versus 27.2%, P = .55; 31.9% versus 30.8%, P = .67). These findings suggest that high-dose Flu was associated with favorable outcomes in the FB group but not in the FM group.

Peripheral blood stem cell transplantation using HLA-haploidentical donor with post-transplant cyclophosphamide versus HLA-matched sibling donor for lymphoma.

Data comparing HLA-haploidentical donors and HLA-matched sibling donors (MSDs) in peripheral blood stem cell transplantation (PBSCT) for lymphoma are scarce. We retrospectively analyzed 465 patients with lymphoma aged 16 years or older who underwent PBSCT using haploidentical donors with post-transplant cyclophosphamide (PTCy-haplo) (n = 166) or MSDs with calcineurin inhibitor-based graft-versus-host disease (GVHD) prophylaxis (n = 299). Two-year overall survival (OS), progression-free survival (PFS), and GVHD-free, relapse-free survival (GRFS) in the PTCy-haplo and MSD groups were 49.2% versus 51.9% (P = 0.64), 38.0% versus 39.9% (P = 0.97), and 27.7% versus 18.5% (P = 0.006), respectively. In multivariable analyses, PTCy-haplo recipients had slower neutrophil recovery (hazard ratio [HR], 0.62; P < 0.001) and platelet recovery (HR, 0.54; P < 0.001), lower risk of chronic GVHD (HR, 0.64; P = 0.038) and extensive chronic GVHD (HR, 0.45; P = 0.008), and better GRFS (HR, 0.66; P = 0.003) than MSD transplant recipients. OS, PFS, relapse or progression, and non-relapse mortality were similar between the groups. The difference might be mainly due to PTCy use rather than donor type; however, the results suggested that PTCy-haplo could be a possible option as an alternative to conventional MSD transplantation for lymphoma in PBSCT.

HLA haploidentical stem cell transplantation from HLA homozygous donors to HLA heterozygous donors may have lower survival rates than haploidentical transplantation from HLA heterozygous donors to HLA heterozygous donors: a retrospective nationwide analysis.

In HLA haploidentical stem cell transplantation, patients and donors usually share one HLA haplotype and have one different HLA haplotype (hetero-to-hetero). However, there are rare cases of transplantation from HLA homozygous donors to heterozygous recipients (homo-to-hetero), resulting in mismatches only in the graft-versus-host direction. We previously reported that homo-to-hetero transplants have a lower survival rate in a mouse model than hetero-to-hetero transplants due to stronger graft-versus-host disease (GVHD) but inferior graft-versus-leukemia effect. To examine whether homo-to-hetero transplant effects also occur in humans, we retrospectively compared the results of 59 homo-to-hetero and 4,539 hetero-to-hetero cases in the Japanese transplant registry data. The results showed no statistical difference between the homo-to-hetero and hetero-to-hetero groups in the cumulative incidences of neutrophil engraftment (83.1% vs 89.0%), acute GVHD II-IV (36.8% vs 38.8%), III-IV (16.8% vs 17.4%), chronic GVHD (32.7% vs 30.7%), relapse (52.9% vs 49.0%), and non-relapse mortality (31.6% vs 28.2%). In contrast, overall survival was significantly lower in the homo-to-hetero group than in the hetero-to-hetero group (12.6% vs 26.2%, p = 0.0308). The inferior effect of homo-to-hetero transplantation on overall survival remained significant in multivariate analyses.

Effect of graft-versus-host disease on outcomes of HLA-haploidentical peripheral blood transplantation using post-transplant cyclophophamide.

There is limited evidence regarding the association between graft-versus-host disease (GVHD) and reduced relapse in patients who undergo allogeneic hematopoietic stem cell transplantation from haploidentical donors (haplo-HSCT) using post-transplant cyclophosphamide (PTCY). We investigated the association between GVHD and transplant outcomes in 938 patients who received haplo-HSCT using PTCY. Overall survival (OS), relapse rate, and non-relapse mortality (NRM) were evaluated using landmark analysis at the landmark points at 100 and 360 days after HSCT for acute and chronic GVHD, respectively. Grade I-II acute GVHD was not associated with OS (adjusted hazard ratio: 1.15, 95% confidence interval: 0.85-1.57), relapse (1.03, 0.74-1.45) and NRM (1.15, 0.74-1.77). Conversely, grade III-IV acute GVHD was associated with higher NRM (3.16, 1.61-6.19), but no other outcomes. Limited chronic GVHD was not associated with OS (1.11, 0.48-1.95), relapse (1.05, 0.30-3.75) and NRM (1.30, 0.45-3.79). Extensive chronic GVHD was associated with higher NRM (2.40, 1.03-5.57), but no other outcome. In conclusion, any GVHD was not associated with a reduced relapse rate and improved OS, and Grade III-IV acute GVHD and extensive chronic GVHD were associated with higher NRM in patients who received haplo-HSCT using PTCY.

Comparison of Allogeneic Transplant Outcomes Between Matched Sibling Donors and Alternative Donors in Patients Over 50 Years of Age with Acute Myeloid Leukemia: 8/8 Allele-Matched Unrelated Donors and Unrelated Cord Blood Provide Better Leukemia-Free Survival Compared with Matched Sibling Donors During Nonremission Status.

Acute myeloid leukemia (AML) is the most common indication for allogeneic hematopoietic cell transplantation (HCT). The increased availability of alternative donor sources has broadened donor types for older patients without HLA-matched sibling donors (MSD). It is uncertain if an MSD should be the first option for allogeneic HCT in patients with AML over 50 years of age. The objective of this study was to compare survival and other post-transplant outcomes between MSDs, 8/8 allele-matched unrelated donors (MUDs), 7/8 allele-MUDs, unrelated cord blood (UCB), and haploidentical donors for patients with AML over 50 years of age. We conducted a retrospective study to compare outcomes in 5704 patients with AML over 50 years of age and receiving allogeneic HCT between 2013 and 2021, using either MSD, 8/8 allele-MUD, 7/8 allele-MUD, UCB, or haploidentical donors in Japan. Complete remission (CR) and nonremission at HCT were analyzed separately for all analyses. In total, 3041 patients were CR, and 2663 patients were nonremission at the time of HCT. In multivariate analysis, donor type did not determine overall survival, irrespective of disease status at HCT. Leukemia-free survival (LFS) was significantly better for 8/8 allele-MUD (hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.64 to 0.93; P = .005) and UCB (HR, 0.76; 95% CI, 0.65 to 0.88; P < .001), but not for 7/8 allele-MUD (HR, 0.97; 95% CI, 0.79 to 1.19; P = .794), and haploidentical donor (HR, 0.86; 95% CI, 0.70 to 1.05; P = .146) compared to the MSD group in nonremission status. However, donor type did not determine LFS among CR status. Relapse rates were significantly lower for 8/8 allele-MUD and UCB, whereas nonrelapse mortality was higher for UCB compared to the MSD group among both CR and nonremission status. Our registry-based study demonstrated that MSDs do not lead to superior survival compared to alternative donors for patients with AML over 50 years of age. Furthermore, 8/8 allele-MUDs and UCB provide better LFS compared with MSDs during nonremission status. Therefore, MSD is not necessarily the best donor option for allogeneic HCT in this population.

HLA-Haploidentical Peripheral Blood Stem Cell Transplantation with Post-Transplantation Cyclophosphamide versus HLA-Matched Unrelated Donor Transplantation for Myelodysplastic Syndrome.

Allogeneic hematopoietic cell transplantation (allo-HCT) is the sole curative therapy for myelodysplastic syndrome (MDS). In the absence of an HLA-matched sibling donor, an HLA-matched unrelated donor (MUD) is considered the leading candidate. However, in recent decades, the alternative donor pool has been extended to HLA-haploidentical donors, especially with the development of graft-versus-host disease (GVHD) prophylaxis using post-transplantation cyclophosphamide (PTCy). Comparative data for haploidentical and MUD allo-HCT in patients with MDS are scarce. We retrospectively analyzed 697 adult patients with MDS who underwent HLA-haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) with PTCy (n = 136), MUD bone marrow transplantation (MUD-BMT) (n = 465), or MUD peripheral blood stem cell transplantation (MUD-PBSCT) (n = 96) as their first allo-HCT between 2014 and 2020 using Japanese registry data. Multivariable analyses demonstrated faster neutrophil engraftment (hazard ratio [HR], 2.19; 95% confidence interval [CI], 1.65 to 2.90; P < .001) and platelet engraftment (HR, 2.31; 95% CI, 1.72 to 3.10; P < 0001) in the MUD-PBSCT cohort compared with the haplo-PBSCT cohort. MUD-BMT was associated with a higher incidence of grade II-IV acute GVHD than haplo-PBSCT (HR, 1.52; 95% CI, 1.00 to 2.29; P = .048). Among patients without in vivo T cell depletion using antithymocyte globulin (ATG) (haplo-PBSCT, n = 136; MUD-BMT, n = 446; MUD-PBSCT, n = 65), MUD-PBSCT recipients experienced faster hematopoietic recovery, MUD-BMT recipients (HR, 1.54; 95% CI, 1.02 to 2.32; P = .042) or MUD-PBSCT recipients (HR, 1.83; 95% CI, 1.06 to 3.18; P = .03) had a higher incidence of grade II-IV acute GVHD, and MUD-PBSCT recipients developed chronic GVHD more frequently than haplo-PBSCT recipients (HR, 1.74; 95% CI, 1.04 to 2.89; P = .034). There were no significant differences in overall survival, disease-free survival, GVHD-free relapse-free survival, relapse, or nonrelapse mortality in the haplo-PBSCT cohort versus the MUD-BMT or MUD-PBSCT cohorts. In conclusion, despite differences in the incidences of hematopoietic engraftment and GVHD depending on graft type and ATG use in MUD transplant recipients, major transplantation outcomes were comparable between recipients of haplo-PBSCT using PTCy and recipients of MUD-BMT or MUD-PBSCT.

Impact of stem cell selection between bone marrow and peripheral blood stem cells for unrelated hematopoietic stem cell transplantation for hematologic malignancies: on behalf of the Donor/Source Working Group of the Japanese Society for Transplantation and Cellular Therapy.

BACKGROUND AIMS: This study aimed to comprehensively assess the impact of stem cell selection between bone marrow (BM) and peripheral blood (PB) in unrelated hematopoietic stem cell transplantation (HSCT) for hematological malignancies. Our objective was to identify specific factors associated with better transplant outcomes. METHODS: A retrospective analysis was conducted using data from the Japanese HSCT registry. Inclusion criteria were patients aged 0-70 years who underwent their first unrelated HSCT with BM or PB, with an 8/8 or 7/8 allele HLA match for hematological malignancies between 2010 and 2020. RESULTS: Among 10 295 patients, no significant difference was observed in overall survival, relapse, graft-versus-host disease (GVHD)-free, relapse-free survival (GRFS) or non-relapse mortality between the groups. Patients who received PB showed no clear difference in acute GVHD but had a greater rate of chronic GVHD, resulting in poor chronic GVHD-free, relapse-free survival (CRFS). Subgroup analyses highlighted the importance of patient-specific factors in source selection. Patients with non-Hodgkin lymphoma and a greater hematopoietic cell transplantation-comorbidity index showed better CRFS and GRFS when BM was the preferred source. Similar trends were observed among patients with standard-risk disease for CRFS. However, no such trends were evident among patients aged 0-24 years, indicating that both sources are viable choices for young patients. CONCLUSIONS: This real-world retrospective analysis showed similar basic outcomes for BM and PB in an unrelated setting. The results support that BM may still be preferred over PB, especially when the long-term quality of life is a major concern. A consideration of individual factors can further optimize transplant success. Further research is warranted to explore the long-term implications of stem cell source selection.

Analysis of risk factors for fatal renal complications after allogeneic hematopoietic cell transplantation.

Various complications can influence hematopoietic cell transplantation (HCT) outcomes. Renal complications can occur during the early to late phases of HCT along with various factors. However, studies focusing on fatal renal complications (FRCs) are scarce. Herein, we analyzed 36,596 first allogeneic HCT recipients retrospectively. Overall, 782 patients died of FRCs at a median of 108 (range, 0-3,440) days after HCT. The cumulative incidence of FRCs was 1.7% and 2.2% at one and five years, respectively. FRCs were associated with older age, male sex, non-complete remission (non-CR), lower performance status (PS), and HCT comorbidity index (HCT-CI) associated with renal comorbidity in multivariate analysis. The risk factors within 100 days included older age, multiple myeloma, PS, and HCT-CI comorbidities (psychiatric disturbance, hepatic disease, obesity, and renal disease). Older age and male sex were risk factors between 100 days and one year. After one year, HCT-CI was associated with the presence of diabetes and prior solid tumor; total body irradiation was identified as a risk factor. Non-CR was a common risk factor in all three phases. Furthermore, acute and chronic graft-versus-host disease, reactivation of cytomegalovirus, and relapse of underlying disease also affected FRCs. Systematic follow-up may be necessary based on the patients' risk factors and post-HCT events.

Low- versus standard-dose post-transplant cyclophosphamide as GVHD prophylaxis for haploidentical transplantation.

Haploidentical haematopoietic cell transplantation (haplo-HCT) using post-transplant cyclophosphamide (PTCY) as graft-versus-host disease (GVHD) prophylaxis is the standard of care for various haematological malignancies. The original PTCY dose after haplo-HCT was 100 mg/kg, but no dose-finding studies have been performed to identify the optimal dose. We performed a retrospective analysis to compare standard-dose PTCY (100 mg/kg) with reduced-dose PTCY (80 mg/kg): 969 in the standard-dose group and 538 in the reduced-dose group. As there was a significant difference between the two groups regarding patient and transplant characteristics, we performed propensity score (PS) matching. After PS matching, 425 patients in each group were included. The probabilities of 2-year OS were 55.9% in the standard-dose group and 47.0% in the reduced-dose group (p = 0.36). The cumulative incidences of 2-year non-relapse mortality were 21.3% in the standard-dose group and 20.5% in the reduced-dose group (p = 0.55). There was no significant difference in the incidence of acute (grade II-IV 29.2% [95% CI, 24.9-33.6] vs. 25.3% [95% CI, 21.3-29.6]; grade III-IV 7.3% [95% CI, 5.1-10.0] vs. 6.6% [95% CI, 4.5-9.3]) or chronic GVHD. In conclusion, reduced- and standard-dose PTCY were comparable in terms of major clinical outcomes.

Outcomes in human T-cell leukemia virus type I carriers after hematopoietic stem cell transplantation for diseases other than adult T cell leukemia/lymphoma: a Japanese national survey.

Background: Human T-cell leukemia virus type I (HTLV-1) is a retrovirus known to cause adult T-cell leukemia/lymphoma (ATL). There are few reports on hematopoietic stem cell transplantation (HSCT) for HTLV-1 carriers with diseases other than ATL. Methods: A total of 25,839 patients (24,399 adults and 1440 children) with pre-transplant HTLV-1 serostatus information recorded in the Japanese National Survey Database who had undergone their first HSCT were analyzed. We investigated the overall survival (OS), transplant-related mortality (TRM), and disease-related mortality (DRM) after HSCT in relation to HTLV-1 serologic status. Findings: Three hundred and forty-eight patients were HTLV-1 antibody carriers. The number of HTLV-1 carriers and noncarriers among adult patients who received allogeneic HSCT (allo-HSCT) or autologous HSCT (auto-HSCT) was 237/15,777 and 95/8920, respectively, and was 16/1424 among pediatric patients who received allo-HSCT. No pediatric HTLV-1 carrier recipients undergoing auto-HSCT were identified. There were no significant differences between HTLV-1 carriers and non-carriers regarding stem cell source, disease risk, or HCT-CI score prior to allo-HSCT. Multivariate analysis of OS (P = 0.020) and TRM (P = 0.017) in adult patients showed that HTLV-1 positive status was a significant prognostic factor. In children, TRM was significantly higher (P = 0.019), but OS was not significantly different. In adult patients who underwent auto-HSCT, HTLV-1 positive status was not a significant prognostic factor. In adult allo-HSCT patients, cytomegalovirus reactivation was significantly more common in HTLV-1 carriers (P = 0.001). Interpretation: HTLV-1 antibody positivity was shown to have a poor prognosis in OS and TRM after allo-HSCT in adult patients and in TRM after allo-HSCT in pediatric patients. Funding: This work was supported in part by the practical research programs of the Japan Agency for Medical Research and Development (AMED) under grant number 17ck0106342h0001.

Evaluating the efficiency and safety of large-volume leukapheresis using the Spectra Optia continuous mononuclear cell collection protocol for peripheral blood stem cell collection from healthy donors: A retrospective study.

BACKGROUND: Large-volume leukapheresis (LVL) refers to processing of more than three volumes of blood in a single session for peripheral blood stem cell collection. Recently, continuous mononuclear cell collection (cMNC) protocol has been developed using the Spectra Optia system, which is a widely used apheresis device. LVL using the novel protocol has been investigated in patients. However, the efficiency and safety of LVL in healthy donors using this protocol has not been characterized. Therefore, this study aimed to evaluate the efficiency and tolerability of CD34+ collection of LVL with the cMNC protocol in healthy donors. STUDY DESIGN AND METHODS: We retrospectively collected data on LVL (>3 total blood volume) and normal-volume leukapheresis (NVL) performed in healthy donors between October 2019 and December 2021. All procedures were performed using the cMNC protocol. RESULTS: Although pre-apheresis CD34+ cell count was lesser in LVL (23.5 vs. 58.0/µL, p < .001), CD34+ collection efficiency was comparable between LVL and NVL (61.2% vs. 61.4%, p = .966). Platelet loss was significantly higher in LVL compared to NVL (38.0% vs. 29.4%, p < .001), with no correlation between attrition of platelet and processing blood volume. Moreover, the incidence of citrate toxicity during procedures was comparable between the two groups (31.6% vs. 21.4%, p = .322). All LVL procedures could be completed without any adverse events. CONCLUSION: Allogeneic LVL procedure using Spectra Optia cMNC protocol was well tolerated by the donors and resulted in efficient collection of CD34+ cells, which was comparable to that of NVL.

Efficacy of gilteritinib in comparison with alectinib for the treatment of ALK-rearranged non-small cell lung cancer.

Gilteritinib is a multitarget tyrosine kinase inhibitor (TKI), approved for the treatment of FLT3-mutant acute myeloid leukemia, with a broad range of activity against several tyrosine kinases including anaplastic lymphoma kinase (ALK). This study investigated the efficacy of gilteritinib against ALK-rearranged non-small cell lung cancers (NSCLC). To this end, we assessed the effects of gilteritinib on cell proliferation, apoptosis, and acquired resistance responses in several ALK-rearranged NSCLC cell lines and mouse xenograft tumor models and compared its efficacy to alectinib, a standard ALK inhibitor. Gilteritinib was significantly more potent than alectinib, as it inhibited cell proliferation at a lower dose, with complete attenuation of growth observed in several ALK-rearranged NSCLC cell lines and no development of drug tolerance. Immunoblotting showed that gilteritinib strongly suppressed phosphorylated ALK and its downstream effectors, as well as mesenchymal-epithelial transition factor (MET) signaling. By comparison, MET signaling was enhanced in alectinib-treated cells. Furthermore, gilteritinib was found to more effectively abolish growth of ALK-rearranged NSCLC xenograft tumors, many of which completely receded. Interleukin-15 (IL-15) mRNA levels were elevated in gilteritinib-treated cells, together with a concomitant increase in the infiltration of tumors by natural killer (NK) cells, as assessed by immunohistochemistry. This suggests that IL-15 production along with NK cell infiltration may constitute components of the gilteritinib-mediated antitumor responses in ALK-rearranged NSCLCs. In conclusion, gilteritinib demonstrated significantly improved antitumor efficacy compared with alectinib against ALK-rearranged NSCLC cells, which can warrant its candidacy for use in anticancer regimens, after further examination in clinical trial settings.

Feasibility of Flow Cytometry Analysis of Gastrointestinal Tract-Residing Lymphocytes in Hematopoietic Stem Cell Transplant Recipients.

The feasibility of lymphocyte isolation and flow cytometry using a single endoscopic biopsy specimen from the gastrointestinal tract of patients who have undergone hematopoietic stem cell transplantation has not been investigated. We acquired 51 endoscopic biopsy specimens from the gastrointestinal tract of 35 patients. We divided the flow cytometry samples into two groups: group A, successful lymphocyte isolation (n=24), and group B, incomplete isolation (n=27). We compared the backgrounds of the samples between the groups to reveal crucial elements in the successful isolation of lymphocytes residing in the gastrointestinal tract. Comparison between the groups revealed lymphocyte isolation success rates differed between biopsy sites. Isolation was most successful in samples from the duodenum (8/9, 88.9%), followed by the ileum (4/8, 50.0%), large intestine (4/11, 36.4%), and stomach (8/23, 34.8%). Tacrolimus was used more frequently in group B (92.6%) than in group A (62.5%) (p=0.015). Logistic regression analysis revealed that isolation from the duodenum or ileum was a significant factor for successful isolation, while tacrolimus use was not statistically significant. In conclusion, the duodenum and ileum are more suitable sites than the stomach and colorectum for acquiring samples for flow cytometry.

Impact of GVHD on lymphoma progression: Nationwide study from Japanese Society for Transplantation and Cellular Therapy.

The graft-versus-lymphoma (GVL) effect and its association with acute and chronic GVHD (aGVHD, cGVHD) has not been comprehensively elucidated. We retrospectively analysed 2204 Japanese patients with non-Hodgkin lymphomas (NHLs; indolent B-NHLs, n = 689; aggressive B-NHLs, n = 720; mature T/NK-NHLs, n = 795) receiving a first allo-HSCT in 2003-2017. Pre-transplant lymphoma control showed complete response (CR) in 759 and non-CR in 1445. We assessed the impact of aGVHD/cGVHD on lymphoma progression and other outcomes. Although aGVHD/cGVHD showed no statistical impact on lymphoma progression in the overall cohort, their impact was clear in certain groups: Grade I-II aGVHD in CR patients (HR, 0.63; 95% CI, 0.43-0.91), especially in mature T/NK-NHL (HR, 0.46; 95% CI, 0.26-0.83) and extensive cGVHD in patients with mature aggressive B-NHLs (HR, 0.55; 95% CI, 0.31-0.97). In total, limited cGVHD was associated with superior survivals (progression-free survival: HR, 0.71; 95% CI, 0.56-0.90), whereas severe GVHDs showed negative impacts on them. Our results support the presence of GVL effects differentially associated with GVHD in different lymphoma subtypes/controls. Meanwhile, it was also suggested that we should manage GVHDs within a limited activity, considering the negative impact of severe GVHDs. As pre-transplant lymphoma control remains a strong factor influencing transplant outcomes, improving its management is an important issue to be addressed.

Distribution and clinical impact of molecular subtypes with dark zone signature of DLBCL in a Japanese real-world study.

The distribution and clinical impact of cell-of-origin (COO) subtypes of diffuse large B-cell lymphoma (DLBCL) outside Western countries remain unknown. Recent literature also suggests that there is an additional COO subtype associated with the germinal center dark zone (DZ) that warrants wider validation to generalize clinical relevance. Here, we assembled a cohort of Japanese patients with untreated DLBCL and determined the refined COO subtypes, which include the DZ signature (DZsig), using the NanoString DLBCL90 assay. To compare the distribution and clinical characteristics of the molecular subtypes, we used a data set from the cohort of British Columbia Cancer (BCC) (n = 804). Through the 1050 patient samples on which DLBCL90 assay was successfully performed in our cohort, 35%, 45%, and 6% of patients were identified to have germinal center B-cell-like (GCB) DLBCL, activated B-cell-like (ABC) DLBCL, and DZsig-positive (DZsigpos) DLBCL, respectively, with the highest prevalence of ABC-DLBCL, differing significantly from the BCC result (P < .001). GCB-DLBCL, ABC-DLBCL, and DZsigpos-DLBCL were associated with 2-year overall survival rates of 88%, 75%, and 66%, respectively (P < .0001), with patients with DZsigpos-DLBCL having the poorest prognosis. In contrast, GCB-DLBCL without DZsig showed excellent outcomes after rituximab-containing immunochemotherapy. DZsigpos-DLBCL was associated with the significant enrichment of tumors with CD10 expression, concurrent MYC/BCL2 expression, and depletion of microenvironmental components (all, P < .05). These results provide evidence of the distinct distribution of clinically relevant molecular subtypes in Japanese DLBCL and that refined COO, as measured by the DLBCL90 assay, is a robust prognostic biomarker that is consistent across geographical areas.