Mitchell Horwitz

Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative treatment for hematologic malignancies and nonmalignant disorders. Rapid immune reconstitution (IR) following allogeneic HCT has been shown to be associated with improved clinical outcomes and lower infection rates. A global phase 3 trial (ClinicalTrials.gov NCT02730299) of omidubicel, an advanced cell therapy manufactured from an appropriately HLA-matched single umbilical cord blood (UCB) unit, showed faster hematopoietic recovery, reduced rates of infection, and shorter hospitalizations in patients randomized to omidubicel compared with those randomized to standard UCB. This optional, prospective substudy of the global phase 3 trial characterized the IR kinetics following HCT with omidubicel compared with UCB in a systematic and detailed manner. This substudy included 37 patients from 14 global sites (omidubicel, n = 17; UCB, n = 20). Peripheral blood samples were collected at 10 predefined time points from 7 to 365 days post-HCT. Flow cytometry immunophenotyping, T cell receptor excision circle quantification, and T cell receptor sequencing were used to evaluate the longitudinal IR kinetics post-transplantation and their association with clinical outcomes. Patient characteristics in the 2 comparator cohorts were overall statistically similar except for age and total body irradiation (TBI)-based conditioning regimens. The median patient age was 30 years (range, 13 to 62 years) for recipients of omidubicel and 43 years (range, 19 to 55 years) for UCB recipients. A TBI-based conditioning regimen was used in 47% of omidubicel recipients and in 70% of UCB recipients. Graft characteristics differed in their cellular composition. Omidubicel recipients received a 33-fold higher median dose of CD34+ stem cells and one-third of the median CD3+ lymphocyte dose infused to UCB recipients. Compared with UCB recipients, omidubicel recipients exhibited faster IR of all measured lymphoid and myelomonocytic subpopulations, predominantly in the first 14 days post-transplantation. This effect involved circulating natural killer (NK) cells, helper T (Th) cells, monocytes, and dendritic cells, with superior long-term B cell recovery from day +28. At 1 week post-HCT, omidubicel recipients exhibited 4.1- and 7.7 -fold increases in the median Th cell and NK cell counts, respectively, compared to UCB recipients. By 3 weeks post-HCT, omidubicel recipients were 3-fold more likely to achieve clinically relevant Th cell and NK cell counts ≥100 cells/µL. Similar to UCB, omidubicel yielded a balanced cellular subpopulation composition and diverse T cell receptor repertoire in both the short term and the long term. Omidubicel's CD34+ cell content correlated with faster IR by day +7 post-HCT, which in turn coincided with earlier hematopoietic recovery. Finally, early NK and Th cell reconstitution correlated with a decreased rate of post-HCT viral infections, suggesting a plausible explanation for this phenomenon among omidubicel recipients in the phase 3 study. Our findings suggest that omidubicel efficiently promotes IR across multiple immune cells, including CD4+ T cells, B cells, NK cells, and dendritic cell subtypes as early as 7 days post-transplantation, potentially endowing recipients of omidubicel with early protective immunity.

The NCCN Guidelines for Hematopoietic Cell Transplantation (HCT) provide an evidence- and consensus-based approach for the use of autologous and allogeneic HCT in the management of malignant diseases in adult patients. HCT is a potentially curative treatment option for patients with certain types of malignancies; however, recurrent malignancy and transplant-related complications often limit the long-term survival of HCT recipients. The purpose of these guidelines is to provide guidance regarding aspects of HCT, including pretransplant recipient evaluation, hematopoietic cell mobilization, and treatment of graft-versus-host disease-a major complication of allogeneic HCT-to enable the patient and clinician to assess management options in the context of an individual patient's condition. These NCCN Guidelines Insights provide a summary of the important recent updates to the NCCN Guidelines for HCT, including the incorporation of a newly developed section on the Principles of Conditioning for HCT.

<jats:title>Abstract</jats:title> <jats:p>BACKGROUND: Our group recently reported on the results of Blood and Marrow Transplant (BMT) Clinical Trials Network (CTN) 1101 a randomized comparison between double umbilical cord blood (dUCB) and haploidentical bone marrow (haplo) with post-transplant cyclophosphamide (ptCy) in the nonmyeloablative setting that showed similar progression free survival (PFS) between the two treatment groups, but lower non-relapse mortality (NRM) and better of overall survival (OS) in the haplo arm. In this secondary analysis we sought to investigate if transplant center experience with haplo and or cord blood HCT had an impact on outcomes.</jats:p> <jats:p>PATIENTS AND METHODS: All patient randomized in BMT CTN 1101 were included. In order to determine the transplant center experience with either haplo or dUCB we queried the Center for International Blood and Marrow Transplant Research (CIBMTR) for number of transplants with each platform in the year prior to initiation of the study. Centers were then grouped as dUCB center (&amp;gt; 10 dUCB, n=117, 10 centers), Haplo center (&amp;gt;10 haplo and ≤10 dUCB, n=110, 2 centers), and ≤10 haplo and ≤10 dUCB HCTs (other center, n=140, 21 centers). Further analysis considered the alternative cut-off for haplo (&amp;gt; 5 vs ≤ 5) experience, and considered the outcomes based on the donor experience vs. others (e.g. dUCB &amp;gt; 10 vs. ≤ 10; haplo &amp;gt; 5 vs. ≤ 5).</jats:p> <jats:p>RESULTS: The effect of center experience on HCT outcomes shown in Figure, below . After adjusting for age, Karnofsky performance score and, disease risk index we found that there was no difference in outcomes between haplo and dUCB for centers that were experienced with dUCB or had limited to no experience with either dUCB or haplo. In contrast, in centers that were primarily experienced with haplo had better outcomes with this donor type, as compared to dUCB. The higher risk of treatment failure (relapse or death) and overall mortality in dUCB in haplo experienced centers was driven by significantly higher risk of relapse. We then considered the transplant experience with each of the donor types separately. In transplant centers that had performed &amp;gt; 10 dUCB, there were similar outcomes for recipients of both dUCB and haplo. Similarly, centers that had ≤ 5 haplo HCTs had no difference in outcomes between donor types suggesting an overlap with centers that had performed &amp;gt; 10 dUCB HCTs. Overall mortality was higher among dUCB recipients in centers that had performed ≤ 10 dUCB. Notably, the hazard ratio of non-relapse mortality favored haplo in all four donor experience type of transplant center, albeit not statistically significant.</jats:p> <jats:p>CONCLUSION: Except for dUCB recipients in centers with &amp;lt; 10 dUCB/year had worse overall mortality, primarily driven by relapse, the transplant center experience in the year prior to the initiation of BMT CTN 1101 had limited impact on the outcomes of this randomized clinical trial.</jats:p> <jats:p>Figure 1 Figure 1.</jats:p> <jats:p /> <jats:sec> <jats:title>Disclosures</jats:title> <jats:p>Brunstein: NANT: Research Funding; FATE: Research Funding; GamidaCell: Research Funding; BlueRock: Research Funding; AlloVir: Consultancy. Costa: Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria. Cutler: Deciphera: Consultancy; Cimeio: Consultancy; Editas: Consultancy; Kadmon: Consultancy; Pfizer: Consultancy; Mallinckrodt: Consultancy; CareDx: Consultancy; Incyte: Consultancy; Omeros: Consultancy; Syndax: Consultancy; Mesoblast: Consultancy; Jazz: Consultancy. Horowitz: Sobi: Research Funding; Regeneron: Research Funding; Orca Biosystems: Research Funding; Tscan: Research Funding; Xenikos: Research Funding; Miltenyi Biotech: Research Funding; Stemcyte: Research Funding; Medac: Research Funding; Vor Biopharma: Research Funding; Kite/Gilead: Research Funding; Janssen: Research Funding; Pharmacyclics: Research Funding; Kiadis: Research Funding; Seattle Genetics: Research Funding; Mesoblast: Research Funding; GlaxoSmithKline: Research Funding; Sanofi: Research Funding; Pfizer, Inc: Research Funding; Omeros: Research Funding; Magenta: Consultancy, Research Funding; Jazz Pharmaceuticals: Research Funding; Vertex: Research Funding; Genentech: Research Funding; Takeda: Research Funding; Novartis: Research Funding; Shire: Research Funding; Gamida Cell: Research Funding; Daiicho Sankyo: Research Funding; CSL Behring: Research Funding; Chimerix: Research Funding; Bristol-Myers Squibb: Research Funding; bluebird bio: Research Funding; Astellas: Research Funding; Amgen: Research Funding; Allovir: Consultancy; Actinium: Research Funding. Horwitz: Gamida Cell: Research Funding. McGuirk: Novartis: Research Funding; Magenta Therapeutics: Consultancy, Honoraria, Research Funding; EcoR1 Capital: Consultancy; Pluristem Therapeutics: Research Funding; Novartis: Research Funding; Bellicum Pharmaceuticals: Research Funding; Astelllas Pharma: Research Funding; Gamida Cell: Research Funding; Fresenius Biotech: Research Funding; Allovir: Consultancy, Honoraria, Research Funding; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Kite/ Gilead: Consultancy, Honoraria, Other: travel accommodations, expense, Kite a Gilead company, Research Funding, Speakers Bureau. Rezvani: US Department of Justice: Consultancy; Kaleido: Other: One-time scientific advisory board; Nohla Therapeutics: Other: One-time scientific advisory board; Pharmacyclics-Abbvie: Research Funding. Rybka: Spark Therapeutics: Consultancy; Merck: Consultancy. Vasu: Kiadis, Inc.: Research Funding; Boehringer Ingelheim: Other: Travel support; Seattle Genetics: Other: travel support; Omeros, Inc.: Membership on an entity's Board of Directors or advisory committees.</jats:p> </jats:sec>