Timing of Initiation of Calcineurin Inhibitors in Pediatric Haploidentical Transplantation with Post-Transplantation Cyclophosphamide: Effects on Survival, Relapse, and Cytokine Release Syndrome

Background: The use of unmanipulated haploidentical stem cell transplantations (haplo-HSCT) with post-transplant cyclophosphamide (PTCY) in children has emerged as an acceptable alternative to the patients without a matched donor. However, the timing of calcineurin inhibitors (CNI) used in combination with PTCY is increasingly becoming a topic of controversy. Method: We evaluated 49 children with acute leukemia who underwent unmanipulated haplo-HSCT with PTCY according to the initiation day of CNIs (pre- or post-CY). Results: There were no significant differences in the overall survival analysis between the two groups. The cumulative incidence of relapse at 2 years was 21.2% in the pre-CY group and 38.9% in the post-CY group (p=0.33). Cytokine release syndrome (CRS) was observed more frequently in the post-CY group (p=0.04). The OS and EFS at 2 years in patients with and without CRS in the pre-Cy group were 42.9% vs 87.5% (p=0.04) and 38.1% vs 87.5% (p=0.04), respectively. Conclusion: Our study shows that the argument for starting CNI administration after CY is tenuous, and the rationale for not starting CNI before CY needs to be reconsidered.

Outcome of Severe Aplastic Anemia Post Allogenic Stem Cell Transplant with Mycophenolate and Calcineurin Inhibitor for Graft Versus Host Disease Prophylaxis

Introduction: Severe aplastic anemia (SAA) is a rare hematopoietic stem cell disorder characterized by hypocellular marrow and pancytopenia. Multiple factors play an important role in treatment approach include age, comorbidities, degree of pancytopenia and availability of stem cell donor to either immunosuppression irrespective (IST) or allogenic hematopoietic stem cell transplant (alloSCT). The use of nonmyeloablative conditioning regimen has improved the outcomes, however the choice for post-transplant GVHD prophylaxis remain a topic of debate. The use of mycophenolate mofetil (MMF) has been used as an alternative for methotrexate (MTX) as has shown to be associated with lower incidence of mucositis and shorter time to engraftment. Methods: We retrospectively evaluated consecutive adult patients with SAA who underwent alloSCT at Karmanoc Cancer Institute. All patients received fludarabine, cyclophosphamide and antithymocyte globulin for conditioning regimen with calcineurin inhibitors (CNI) and MMF for GVHD prophylaxis. MMF was started at day -3 at 15 mg/kg three times daily and stopped at day +30 in the absence of active GVHD. The primary objectives were to estimate cumulative incidence of acute (aGVHD) and chronic GVHD (cGVHD) and overall survival (OS). Secondary objectives were to evaluate time to engraftment, days of hospitalization and incidence of mucositis. Results: From January 2005 and May 2019, 33 patients with SAA underwent alloSCT. Patient characteristics are detailed in Table 1. Median age was 36 years (range, 18-71). Twenty-seven patients received bone marrow stem cells (82%) and six patients received peripheral blood stem cells (18%). Thirty patients (91%) received 8/8 HLA matched donor and three patients (9%) received 7/8 HLA matched donor. Sixteen patients (48%) received stem cells from sibling donor and 17 patients (52%) received stem cells from unrelated donor. Thirteen patients (39%) had received IST prior to alloSCT, and 20 patients (61%) received upfront alloSCT. For GVHD prophylaxis all patients received MMF and CNI (tacrolimus=32, and cyclosporine=1). Median time from diagnosis to transplant was 15.8 months for patients who received IST prior to alloSCT and 2 months for patients who received upfront alloSCT. Median time to platelet engraftment was 13.5 days and neutrophil engraftment was 12 days, while one patient experienced graft failure. The median number of days for hospital stay were 25 days. Four patients (11%) developed grade I-II mucositis, no grade III-IV mucositis was observed in the first 30 days and 6 patients had CMV reactivation. The 100-day cumulative incidence rate of grade II-IV aGVHD was 21.2% (95% CI, 9.2 - 36.5), grade III-IV aGVHD was 9.1% (2.3-21.9) and 1-year CIR of cGVHD was 21.2% (95% CI, 9.2-36.5). Comparing patients who received IST prior to alloSCT versus upfront alloSCT, the 100-day CIR of grade II-IV aGVHD was 30.8% (95% CI, 8.2 - 56.5) and 15% (95% CI, 3.6 - 34.0), respectively, (Gray p=0.26) and the 3-year CIR of cGVHD was 39.6% (95% CI, 13.1 - 65.5) and 27.8% (95% CI, 9.2 - 50.3), respectively, (Gray p=0.37). Comparing patients who received alloSCT from related versus unrelated donor, 100-day CIR of II-IV aGVHD was 12.5% (95% CI, 1.9 - 33.6) and 29.4% (95% CI, 10.2 - 51.9), respectively, (Gray p=0.26), and the 3-year CIR of cGVHD was 34.2% (95% CI, 11.4 - 58.9) and 29.4% (95% CI, 10.1 - 52.0), respectively (Gray p=0.90). Median follow up of surviving patient was 5 years (95% CI, 3.1-6.8). Three-year OS was 87% (95% CI, 75.7- 99.9) and median OS was not reached. Six patients died by the time of the analysis, one patient died from graft failure (86 days after transplant from 8/8 HLA MUD), two patients died due infectious complications (808 days and 1637 days after transplant), three patients died due to multiorgan failure (215, 297 and 1097 days after transplant). Conclusion: Our data with use of CNI and MMF for GVHD prophylaxis for SAA following alloSCT with nonmyeloablative conditioning regimen showed that the rate of mucositis was low, engraftment time was rapid, and hospitalization was short, while OS, rates of acute and chronic GVDH were comparable to previously published rates with CNI and MTX-based GVHD prophylaxis. Figure 1 Figure 1. Disclosures Modi: Genentech: Research Funding; Seagen: Membership on an entity's Board of Directors or advisory committees; MorphoSys: Membership on an entity's Board of Directors or advisory committees. Deol: Kite, a Gilead Company: Consultancy.

Outcomes with Mismatched Unrelated Donor Allogeneic Hematopoietic Stem Cell Transplantation Following Reduced Intensity Conditioning: A Systematic Review and Meta-Analysis

Background: Allogeneic hematopoietic cell transplantation (HSCT) is often the optimal and only potentially curative therapy in several high-risk hematologic malignancies. Although human leukocyte antigen (HLA)-matched donors remain the preferred choice for HSCT recipients, haploidentical and umbilical cord blood HSCT has increased access to transplantation. Despite these advances, many patients lack an appropriate donor, in particular the ethnic minorities. The use of mismatched unrelated donors (MMUD) has increased over the years but concerns regarding increased risk of graft versus host disease (GVHD) and non-relapse mortality (NRM) limits the utility of MMUD HSCT. The intensity of the conditioning regimen has a significant impact on survival in case of mismatched donors. We conducted a systematic review and meta-analysis aimed to investigate the outcomes with MMUD HSCT using reduced intensity conditioning (RIC). Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, a comprehensive literature search was performed on three databases (PubMed, Cochrane Library, and ClinicalTrials.gov) from date of inception through February 2021 using the MeSH and entry terms for "hematopoietic stem cell transplantation", OR "hematologic neoplasms", AND unrelated donors" AND "treatment outcome". A total of 2477 records were identified and primary and secondary screening was done. After excluding review, duplicate, and non-relevant articles, we included 6 (4 retrospective, 2 prospective) studies reporting outcomes following RIC MMUD HSCT. The Joanna Briggs Institute (JBI) critical appraisal checklist for studies reporting prevalence data and randomized control trial was used for quality assessment, and all studies were reported as good. Proportions along with a 95% confidence interval (CI) were extracted to compute pooled analysis using the 'meta' package by Schwarzer et al. in the R programming language (version 4.16-2). The variance between the studies was calculated using Der Simonian Laird Estimator. Results: We identified 895 participants in the 6 studies, who had MMUD HSCT with RIC. (Table 1) Median age was 57.5 (18-76) years and 56% (n= 415) were males as reported by four studies (n=740). In five studies with available data (n=855), source of the primary graft was peripheral blood (PB) and bone marrow (BM) in 72% (n=614) and 28% (n=241) of the HSCT recipients respectively. After a median follow-up of 48 (3-125) months, we estimated a pooled overall survival (OS) of 62% (95% CI 0.52-0.72, I 2=84%, n=895) at one year and 43.5% (95% CI 0.33-0.54, I 2 =84% n=855) at three years. The pooled incidence of acute GVHD (grade II-IV), acute GVHD (grade III-IV), and chronic GVHD were 37% (95% CI 0.26-0.49, I 2=81%, n=610), 16% (95% CI 0.07-0.29, I 2=87%, n=542), and 28% (95% CI 0.13-0.47, I 2=95%, n=848) respectively. Progression free survival (PFS) and relapse rates (RR) were 46% (95% CI 0.30-0.62, I 2=92%, n=814) and 31% (95% CI 0.24-0.39, I 2=65%, n=814) respectively. The pooled incidence of non-relapse mortality (NRM) was 23% (95% CI 0.09-0.40, I 2=91%, n=707). Kasamon et al. and Shaw et al. reported 1-year OS of 75-79% with MMUD HSCT using fludarabine, cyclophosphamide and 2 Gy total body irradiation RIC, bone marrow graft and post-transplant cyclophosphamide, sirolimus and mycophenolate for GVHD prophylaxis. Conclusion: Mismatched unrelated donor HSCT has shown favorable outcomes with reduced intensity conditioning using a post-transplant cyclophosphamide-based regimen, comparable to the historical outcomes with mismatched related donor (haploidentical) HSCT. MMUD HSCT with RIC can be considered in patients lacking an HLA-matched donor. This strategy will expand access to HSCT in patients with ethnic minorities who often lack a matched donor. Figure 1 Figure 1. Disclosures McGuirk: EcoR1 Capital: Consultancy; Allovir: Consultancy, Honoraria, Research Funding; Gamida Cell: Research Funding; Novartis: Research Funding; Kite/ Gilead: Consultancy, Honoraria, Other: travel accommodations, expense, Kite a Gilead company, Research Funding, Speakers Bureau; Astelllas Pharma: Research Funding; Fresenius Biotech: Research Funding; Bellicum Pharmaceuticals: Research Funding; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Novartis: Research Funding; Magenta Therapeutics: Consultancy, Honoraria, Research Funding; Pluristem Therapeutics: Research Funding.

Outcomes with Mismatched Unrelated Donor Allogeneic Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-Analysis

Background Allogeneic hematopoietic stem cell transplantation (HCT) is the optimal and potentially curative therapy in various high-risk hematologic malignancies. Although a human leukocyte antigen (HLA)-matched sibling or unrelated donor is a clinically preferred stem cell source, the use of haploidentical family donors and umbilical cord blood HCT now offers the option of HCT in patients lacking a matched donor. However, many patients lack an appropriate donor, in particular the ethnic minorities. Mismatched unrelated donors (MMUD) have historically been utilized as alternative donor source for these patients due to ease of donor availability but is associated with increased risk of graft versus host disease (GVHD) and non-relapse mortality (NRM). In this systematic review and meta-analysis, we aimed to assess the outcomes with MMUD HCT. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, a comprehensive literature search was performed on three databases (PubMed, Cochrane Library, and ClinicalTrials.gov) from date of inception through February 2021 using the MeSH and entry terms for "hematopoietic stem cell transplantation", OR "hematologic neoplasms", AND unrelated donors" AND "treatment outcome". A total of 2477 records were identified and primary and secondary screening was done. After excluding review, duplicate, and non-relevant articles, we included 13 studies (11 retrospective, 2 prospective) reporting outcomes following MMUD HCT. The Joanna Briggs Institute (JBI) critical appraisal checklist for studies reporting prevalence data and randomized control trial was used for quality assessment, and all studies were reported as good. Proportions along with a 95% confidence interval (CI) were extracted to compute pooled analysis using the 'meta' package by Schwarzer et al. in the R programming language (version 4.16-2). The variance between the studies was calculated using Der Simonian-Laird Estimator. Results: We identified 2588 patients from 13 included studies who had MMUD HCT. (Table 1) Median age was 51.7 (18-76) years and 52% (n=1347) were males. Source of primary graft was bone marrow (BM) in 19% (n=478/2508) and peripheral blood (PB) in 81% (n=2030/2508) HCT recipients. Median time to transplant was 10.45 (1.5-139.6) months and median follow up was 41.5 (0.4-136.5) months. Reduced intensity conditioning (RIC) conditioning was used for 73% (n=1884) of the patients while 27.2% (n= 704) patients received myeloablative conditioning (MAC). We estimated a pooled overall survival (OS) of 59% (95% CI 0.52-0.66, I 2 = 92%, n=2563) at one year and 44% (0.36-0.53, I 2=92%, n=1972) at three years. The pooled incidence of acute GVHD (grade II-IV), acute GVHD (grade III-IV), and chronic GVHD were 39% (95% CI 0.33-0.44, I 2=84%, n=2282), 19% (95% CI 0.15-0.23, I 2=65%, n=1417), and 38% (95% CI 0.32-0.47, I 2=93%, n=2477) respectively. Progression free survival (PFS) was 39.5% (95% CI 0.31-0.48, I 2=94% n=2505). The pooled incidence of relapse rate (RR) and NRM were 31% (95% CI 0.25-0.38, I 2=90%, n=2482) and 27% (95% CI 0.21-0.34, I 2 =90% n=2448) respectively. Conclusion: Mismatched unrelated donor HCT has shown favorable outcomes with acceptable toxicity profile. MMUD HCT represents a promising option for patients lacking an HLA-matched donor and has expanded access to HCT in patients with ethnic minorities who often lack a matched donor. Figure 1 Figure 1. Disclosures Abhyankar: Incyte/Therakos: Consultancy, Research Funding, Speakers Bureau. McGuirk: Juno Therapeutics: Consultancy, Honoraria, Research Funding; Fresenius Biotech: Research Funding; Novartis: Research Funding; Gamida Cell: Research Funding; Magenta Therapeutics: Consultancy, Honoraria, Research Funding; Pluristem Therapeutics: Research Funding; Allovir: Consultancy, Honoraria, Research Funding; EcoR1 Capital: Consultancy; Kite/ Gilead: Consultancy, Honoraria, Other: travel accommodations, expense, Kite a Gilead company, Research Funding, Speakers Bureau; Astelllas Pharma: Research Funding; Bellicum Pharmaceuticals: Research Funding; Novartis: Research Funding.

Post-Transplant Cyclophosphamide Versus Tacrolimus and Methotrexate to Prevent Graft-Versus-Host Disease in Recipients of Matched Donor Transplantation: Comparison of Sequential Cohorts in a Prospective Trial

Background: Myeloablative conditioning can be given safely to older patients by simply administering busulfan over a longer period (fractionated busulfan regimen) than our "standard" four-day fludarabine-busulfan (Flu-Bu) regimen. (Popat et al Lancet Haematology 2018). To further improve outcomes of this fractionated (f-Bu) regimen in patients undergoing matched donor hematopoietic cell transplantation (HCT), we added cladribine (Clad) to f-Bu-Flu regimen in a prospective clinical trial (NCT02250937). GVHD prophylaxis was tacrolimus and methotrexate (Tac/MTX). After enrolling the first 29 patients, the study was amended and GVHD prophylaxis was changed to post-transplant cyclophosphamide (PTCy) and tacrolimus for the next 53 patients based on very promising data observed in patients undergoing haploidentical transplantation. We hypothesized that PTCy will reduce GVHD and non-relapse mortality (NRM), thus improving survival in patients undergoing HCT from a matched donor. In this study, we compared these two sequential cohorts with reference to GVHD prophylaxis. Methods: Between 2/2015 and 12/2018, 82 patients with AML or MDS, 18-70 years of age, with adequate organ function and 8/8-HLA matched related (n=38%) or unrelated (62%) donors were enrolled. The conditioning regimen was f-Bu to target an area under the concentration vs time curve (AUC) of 20,000 ± 12% μmol.min given over a period of 2-3 weeks. The first two doses of busulfan (80 mg/m2 IV each) were administered either consecutively (days -13 and -12) or with further fractionation, one week apart (days -20 and -13) on outpatient basis. Then, inpatient fludarabine 10 mg/m 2, and cladribine 10 mg/m 2 were given followed by Bu on days -6 to -3. GVHD prophylaxis was Tac/Mtx (n=29) or PTCy 50mg/kg on days 3 and 4 followed by tacrolimus from day 5 (n=53). Results: Baseline characteristics were similar between the PTCy and Tac/Mtx cohorts. The median age was 59 (range, 18-70) and 61 (range, 24-70) years (P=0.20); 49% and 59% had primary induction failure at HCT (P=0.58); High or very-high disease risk index was present in 40% and 41%, (P=0.40); Comorbidity index score >3 was present in 42% and 40% (P=0.24); Donor was a sibling in 34% and 45% (P=0.35), and peripheral blood graft was used in 81% and 76% (P=0.58), respectively in PTCy and Tac/Mtx cohorts. Median follow up was 42.7 months. In the PTCy and Tac/Mtx cohorts, at 3-years overall survival was 69% vs 38% (P=0.0004), NRM was 8% vs 28% (P=0.009) [Table 1, Figure 1], incidence of grade 3-4 acute GVHD at day 100 was 4% vs 17% (P=0.04), and chronic GVHD was 21% vs 28% at 3 years (P=0.53). Median time to neutrophil engraftment was prolonged by 3 days with PTCy (15 vs 12 days; P<0.0001). Full donor chimerism at day 30 was noted in 81% vs 28%, in the PTCy and Tac/Mtx cohorts respectively, (P=0.005). The toxicity profile was similar except neutropenic fever (likely cytokine-related) was higher in PTCy group (60% v/s 24%, P=0.002). Likewise, the incidence of hemorrhagic cystitis was higher in the PTCy group (36% vs 14%, p-0.04). Most of the later events were grade 1 or 2. Conclusion: Compared with Tac/Mtx, PTCy reduced severe acute GVHD and NRM, and improved survival in AML/MDS patients up to the age of 70 years who received myeloablative fractionated busulfan conditioning and transplant from a matched donor. Figure 1 Figure 1. Disclosures Popat: Bayer: Research Funding; Abbvie: Research Funding; Novartis: Research Funding; Incyte: Research Funding. Mehta: CSLBehring: Research Funding; Kadmon: Research Funding; Syndax: Research Funding; Incyte: Research Funding. Hosing: Nkarta Therapeutics: Membership on an entity's Board of Directors or advisory committees. Rezvani: Navan Technologies: Other: Scientific Advisory Board; Caribou: Other: Scientific Advisory Board; GemoAb: Other: Scientific Advisory Board ; GSK: Other: Scientific Advisory Board ; Pharmacyclics: Other: Educational grant, Research Funding; Bayer: Other: Scientific Advisory Board ; Takeda: Other: License agreement and research agreement, Patents & Royalties; Affimed: Other: License agreement and research agreement; education grant, Patents & Royalties, Research Funding; Virogin: Other: Scientific Advisory Board ; AvengeBio: Other: Scientific Advisory Board . Qazilbash: Janssen: Research Funding; Biolline: Research Funding; Oncopeptides: Other: Advisory Board; NexImmune: Research Funding; Angiocrine: Research Funding; Amgen: Research Funding; Bristol-Myers Squibb: Other: Advisory Board. Kadia: Liberum: Consultancy; AstraZeneca: Other; Sanofi-Aventis: Consultancy; Genfleet: Other; Pulmotech: Other; Dalichi Sankyo: Consultancy; Genentech: Consultancy, Other: Grant/research support; Amgen: Other: Grant/research support; Astellas: Other; Jazz: Consultancy; Aglos: Consultancy; Ascentage: Other; Cellonkos: Other; Novartis: Consultancy; Pfizer: Consultancy, Other; AbbVie: Consultancy, Other: Grant/research support; BMS: Other: Grant/research support; Cure: Speakers Bureau. Kantarjian: BMS: Research Funding; Daiichi-Sankyo: Research Funding; Pfizer: Honoraria, Research Funding; KAHR Medical Ltd: Honoraria; Novartis: Honoraria, Research Funding; Jazz: Research Funding; Precision Biosciences: Honoraria; Amgen: Honoraria, Research Funding; Aptitude Health: Honoraria; Immunogen: Research Funding; Ascentage: Research Funding; AbbVie: Honoraria, Research Funding; NOVA Research: Honoraria; Ipsen Pharmaceuticals: Honoraria; Astellas Health: Honoraria; Astra Zeneca: Honoraria; Taiho Pharmaceutical Canada: Honoraria. Shpall: Adaptimmune: Consultancy; Magenta: Consultancy; Novartis: Honoraria; Affimed: Patents & Royalties; Navan: Consultancy; Magenta: Honoraria; Novartis: Consultancy; Takeda: Patents & Royalties; Bayer HealthCare Pharmaceuticals: Honoraria; Axio: Consultancy.

A Calcineurin Inhibitor Free Graft Versus Host Disease (GVHD) Prophylaxis for Patients Undergoing Matched Related (MRD) and Matched Unrelated Donor (MUD) Allogeneic Hematopoietic Cell Transplant (Allo-HCT)

Introduction Post-transplantation cyclophosphamide (PTCy) and calcineurin inhibitor (CNI) based GVHD prophylaxis has shown lower rates of acute and chronic GVHD when compared with the traditional prophylaxis of calcineurin inhibitor (CNI) and methotrexate (MTX) in matched donor (related and unrelated) allo-HCT. The combination of PTCy with sirolimus as a calcineurin inhibitor-free GVHD prophylaxis has shown promising results with cumulative rates of grade II-IV acute and chronic GVHD in the range of 15-27% and 20-27% respectively in patients undergoing matched and haploidentical allo-HCT. We report a single center, nonrandomized comparison of patients undergoing matched donor allo-HCT receiving PTCy in combination with sirolimus (PTCy/Siro) with those receiving the standard GVHD prophylaxis of tacrolimus and MTX (Tac/MTX). Methods One hundred and sixteen consecutive patients who had undergone a MRD or MUD allo-HCT between January 2018 to January 2021 and received either PTCy with sirolimus or tacrolimus with methotrexate as GVHD prophylaxis regimens were eligible for inclusion. The selection of PTCy with sirolimus or tacrolimus with methotrexate as GVHD prophylaxis regimen was based on physician choice. Primary endpoints were cumulative incidence of acute (grade II to IV) and chronic GVHD. Secondary endpoints were a) neutrophil and platelet engraftment; b) overall survival (OS); c) non-relapse mortality (NRM); d) relapse; e) clinical infections and f) time to immunosuppression (IS) withdrawal. Kaplan-Meier method was used to estimate 1-year and 2-year freedom from long term adverse events, including chronic GVHD, relapse, NRM and OS. All tests were two-sided with alpha level set at 0.05 for statistical significance. Results Out of a total of 116 patients undergoing MRD and MUD allo-HCT, 29 received PTCy/Siro and 87 Tac/MTX. Baseline characteristics were similar between the two arms except patients in PTCy/Siro were younger with median of 48 (range: 24-69) years vs. 61 (range: 20-73) years (p=0.004) in Tac/MTX. There was difference in primary indication for allo-HCT between the two arms with non-hodgkin lymphoma (NHL) being the most common in PTCy/Siro and acute myeloid leukemia (AML) in the Tac/MTX group. Patients receiving PTCy/Siro had a significantly higher median CD3 day 100 chimerism at 100 (90-100) vs. 90 (40-100) % (<0.001) and a significantly shorter median time to IS withdrawal at 138 (37-312) vs 232(66-1120) days for patients receiving Tac/MTX. There was no difference between the two arms for length of hospital stay and time to neutrophil engraftment, but PTCy/Siro had a significantly longer median time for platelet engraftment at 17.5 (12-74) vs.14 (11-38) days (p= 0.001). No significant difference was observed between the two arms for incidence of grade II to IV acute GVHD, grade III to IV acute GVHD, steroid refractory acute GVHD or clinical infections (Table 1). After a median follow up of 1.1 (range: 0-1.8) years, patients receiving PTCy/Siro were significantly less likely to have chronic GVHD with 2-year freedom from GVHD of 75% (95%CI: 58-98%) vs 20% (95%CI 10-40%), p=0.005 (Figure 1). There was no difference between the two arms for OS, disease relapse or non-relapse mortality (Table 2). Conclusion In this study, the combination of PTCy/Siro is associated with a significantly lower risk of chronic GVHD when compared against the traditional GVHD prophylaxis of CNI and methotrexate, despite significantly earlier IS withdrawal. Other long-term outcomes of interest remained comparable between the two arms. Chronic GVHD contributes to significant morbidity and mortality in patients undergoing allo-HCT. Newer strategies to limit the impact of chronic GVHD are needed. The results of our study warrant validation in a large, multicenter, randomized prospective trial. Figure 1 Figure 1. Disclosures Murthy: CRISPR Therapeutics: Research Funding. Foran: gamida: Honoraria; takeda: Research Funding; novartis: Honoraria; trillium: Research Funding; boehringer ingelheim: Research Funding; OncLive: Honoraria; abbvie: Research Funding; certara: Honoraria; sanofi aventis: Honoraria; syros: Honoraria; taiho: Honoraria; revolution medicine: Honoraria; bms: Honoraria; servier: Honoraria; pfizer: Honoraria; actinium: Research Funding; aptose: Research Funding; kura: Research Funding; h3bioscience: Research Funding; aprea: Research Funding; sellas: Research Funding; stemline: Research Funding.

Allogeneic Hematopoietic Stem Cell Transplantation in Patients Older than 65 Years with Acute Myeloid Leukemia and Myelodysplastic Syndrome: A 15-Year Experience

Background. Median age of occurrence of acute myeloid leukemias (AML) and myelodisplastc syndromes (MDS) is 65 years and older. Nevertheless, the use of allogeneic stem cell transplant (allo-HCT) has been historically limited to younger population, namely due to excess in non-relapse-mortality (NRM) in olders. Methods. In the present study, we analyzed all consecutive patients aged ≥ 65y diagnosed with AML (71, 81%) or MDS (19, 19%) who received transplants from adult donors at our center from January 2005 to December 2019. Results. Median age was 68.29y (65.02-76.54), 26pts (29%) aged ≥ 70y. Thirty-three (37%) pts received a HLA-matched donor. Conditioning regimen was myeloablative in 46pts (51%). The 3-year overall survival (OS) was 53+/-6%, and disease free survival (DFS) 45+/-6% (Figure 1). Day-100 and 3-year NRM was 17+/-2% and 29+/-2%, respectively. The 3-year CI of relapse was 22+/-2%. Day-100 CI of aGvHD was 21+/-2% for grade II-IV, 14+/-1% for grade III-IV. The 3-year CI of cGvHD was 35+/-3%, extensive 20+/-2%. In multivariate analysis, the Karnofsky Performance Status (KPS) < 90% was associated with lower OS (HR: 2.999, CI: 1.477- 6.691; p=0.002), DFS (HR: 3.155, CI: 1.593 - 6.250; p=0.001) and higher NRM (HR: 2.997, CI: 1.344-6.682; p=0.041). HCT-CI ≥ 3 was also associated with higher NRM (HR: 2.949, CI: 1.166-7.462, p=0.022,). Diagnosis of MDS and receiving a matched donor with PTCy were associated with longer OS (HR: 0.3440, CI: 0.1029-0.915; p=0.033; HR: 0.197, CI: 0.042-0.934; p=0.041).Conclusions. Age alone should not limit transplant eligibility for AML and MDS. KPS and HCT-CI proved to be useful for patient selection among the elderly. The use of HLA-matched donors with PTCy improved OS compared to ATG in our consecutive series.

Development of artificial blood vessels made of new materials, used for vascular access in renal dialysis

It can take many years to find a matched kidney donor and, in some cases, a matched donor is never found. Dialysis machines and methods of accessing a patient's cardiovascular system mean patients can live well whilst waiting for a transplant. Patients must undergo one of two surgical procedures before their first haemodialysis; receiving either an arteriovenous fistula or an arteriovenous graft, which join the artery to the vein and facilitate the transfer of blood from body to machine. If a graft is needed, an operation to insert a polytetrafluoroethylene (PTFE) based device is required but complications can arise in the form of blockages. Denan Jin, Department of Innovative Medicine, Osaka Medical and Pharmaceutical University, Japan, has spent years conducting research on the issues related to PTFE device blockage. He worked with his mentor Professor Mizuo Myazaki before his retirement and his colleague Professor Shinji Takai, and these collaborations led to understanding of the major causes of these blockages. Jin and his team are working to develop means to increase the longevity of PTFE grafts. The researchers have discovered two key mechanisms through which the grafts become blocked, which has led to the identification of two possible routes for preventing blockages. These relate to fibroblasts and the researchers have also identified the enzyme chymase as a key intermediate in the process of fibroblast recruitment. Jin and the team are proposing the use of an alternative to PTFE and the development of an effective chymase inhibitor to reduce the recruitment of fibroblasts to the graft site.

Biologic Assignment Trial of Reduced-Intensity Hematopoietic Cell Transplantation Based on Donor Availability in Patients 50-75 Years of Age With Advanced Myelodysplastic Syndrome

PURPOSE Allogeneic hematopoietic cell transplantation (HCT) is the only potentially curative therapy for myelodysplastic syndromes (MDS), although it is infrequently offered to older patients. The relative benefits of HCT over non-HCT therapy in older patients with higher-risk MDS have not been defined. METHODS We conducted a multicenter biologic assignment trial comparing reduced-intensity HCT to hypomethylating therapy or best supportive care in subjects 50-75 years of age with intermediate-2 or high-risk de novo MDS. The primary outcome was overall survival probability at 3 years. Between January 2014 and November 2018, we enrolled 384 subjects at 34 centers. Subjects were assigned to the Donor or No-Donor arms according to the availability of a matched donor within 90 days of study registration. RESULTS The median follow-up time for surviving subjects was 34.2 months (range: 2.3-38 months) in the Donor arm and 26.9 months (range: 2.4-37.2 months) in the No-Donor arm. In an intention-to-treat analysis, the adjusted overall survival rate at 3 years in the Donor arm was 47.9% (95% CI, 41.3 to 54.1) compared with 26.6% (95% CI, 18.4 to 35.6) in the No-Donor arm ( P = .0001) with an absolute difference of 21.3% (95% CI, 10.2 to 31.8). Leukemia-free survival at 3 years was greater in the Donor arm (35.8%; 95% CI, 29.8 to 41.8) compared with the No-Donor arm (20.6%; 95% CI, 13.3 to 29.1; P = .003). The survival benefit was seen across all subgroups examined. CONCLUSION We observed a significant survival advantage in older subjects with higher-risk MDS who have a matched donor identified and underwent reduced-intensity HCT, when compared with those without a donor. HCT should be included as an integral part of MDS management plans in fit older adults with higher-risk MDS.

Haploidentical Hematopoietic Cell Transplantation Using Post-transplant Cyclophosphamide for Children With Non-malignant Diseases

Haploidentical hematopoietic cell transplantation (HCT) is a valuable curative option for children with non-malignant diseases. Haploidentical HCT using post-transplant cyclophosphamide (PTCy) is a readily available option in the absence of an HLA- matched donor. We conducted a retrospective single-center study on the outcome of haploidentical HCT in children with non-malignant diseases. We gathered data from 44 patients underwent HCT in the period 2015 to 2020. The indications for HCT were bone marrow failure, primary immunodeficiency, metabolic disorders, and hemoglobinopathy. Median age at HCT was 4 years (range 0.7-20).The conditioning regimens were myeloablative (n=16), or reduced intensity (n=26). After a median follow-up of 20 months (range 4-71), 2-year overall survival was 89% and 2 year GvHD-free relapse-free survival (GRFS) was 66%. Incidence of primary graft failure was 13.6%. Cumulative incidence of grade II-IV acute and moderate/severe chronic GvHD were 20% and 6.4%, respectively. Younger age at HCT (<5 years) and primary immunodeficiency were significantly associated with better GRFS (p <0.05). In conclusion, haploidentical HCT using PTCy is feasible and curative in children with non-malignant diseases lacking an HLA-matched donor. Early diagnosis and referral in addition to timely treatment can further improve outcomes.