Julianne Chen

Human Bone Marrow–Derived Mesenchymal Stem Cells in the Treatment of Gliomas

The poor survival of patients with human malignant gliomas relates partly to the inability to deliver therapeutic agents to the tumor. Because it has been suggested that circulating bone marrow-derived stem cells can be recruited into solid organs in response to tissue stresses, we hypothesized that human bone marrow-derived mesenchymal stem cells (hMSC) may have a tropism for brain tumors and thus could be used as delivery vehicles for glioma therapy. To test this, we isolated hMSCs from bone marrow of normal volunteers, fluorescently labeled the cells, and injected them into the carotid artery of mice bearing human glioma intracranial xenografts (U87, U251, and LN229). hMSCs were seen exclusively within the brain tumors regardless of whether the cells were injected into the ipsilateral or contralateral carotid artery. In contrast, intracarotid injections of fibroblasts or U87 glioma cells resulted in widespread distribution of delivered cells without tumor specificity. To assess the potential of hMSCs to track human gliomas, we injected hMSCs directly into the cerebral hemisphere opposite an established human glioma and showed that the hMSCs were capable of migrating into the xenograft in vivo. Likewise, in vitro Matrigel invasion assays showed that conditioned medium from gliomas, but not from fibroblasts or astrocytes, supported the migration of hMSCs and that platelet-derived growth factor, epidermal growth factor, or stromal cell-derived factor-1alpha, but not basic fibroblast growth factor or vascular endothelial growth factor, enhanced hMSC migration. To test the potential of hMSCs to deliver a therapeutic agent, hMSCs were engineered to release IFN-beta (hMSC-IFN-beta). In vitro coculture and Transwell experiments showed the efficacy of hMSC-IFN-beta against human gliomas. In vivo experiments showed that treatment of human U87 intracranial glioma xenografts with hMSC-IFN-beta significantly increase animal survival compared with controls (P < 0.05). We conclude that hMSCs can integrate into human gliomas after intravascular or local delivery, that this engraftment may be mediated by growth factors, and that this tropism of hMSCs for human gliomas can be exploited to therapeutic advantage.

Improved Early Outcomes Using a T Cell Replete Graft Compared with T Cell Depleted Haploidentical Hematopoietic Stem Cell Transplantation

Haploidentical stem cell transplantation (SCT) has been generally performed using a T cell depleted (TCD) graft; however, a high rate of nonrelapse mortality (NRM) has been reported, particularly in adult patients. We hypothesized that using a T cell replete (TCR) graft followed by effective posttransplantation immunosuppressive therapy would reduce NRM and improve outcomes. We analyzed 65 consecutive adult patients with hematologic malignancies who received TCR (N = 32) or TCD (N = 33) haploidentical transplants. All patients received a preparative regimen consisting of melphalan, fludarabine, and thiotepa. The TCR group received posttransplantation treatment with cyclophosphamide (Cy), tacrolimus (Tac), and mycophenolate mofetil (MMF). Patients with TCD received antithymocyte globulin followed by infusion of CD34+ selected cells with no posttransplantation immunosuppression. The majority of patients in each group had active disease at the time of transplantation. Outcomes are reported for the TCR and TCD recipients, respectively. Engraftment was achieved in 94% versus 81% (P = NS). NRM at 1 year was 16% versus 42% (P = .02). Actuarial overall survival (OS) and progression-free survival (PFS) rates at 1 year posttransplantation were 64% versus 30% (P = .02) and 50% versus 21% (P = .02). The cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was 20% versus 11% (P = .20), and chronic GVHD (cGVHD) 7% versus 18% (P = .03). Improved reconstitution of T cell subsets and a lower rate of infection were observed in the TCR group. These results indicate that a TCR graft followed by effective control of GVHD posttransplantation may lower NRM and improve survival after haploidentical SCT.

Treatment of FLT3-ITD-positive acute myeloid leukemia relapsing after allogeneic stem cell transplantation with sorafenib.

Patients with acute myeloid leukemia (AML) and internal tandem duplication of FMS-like tyrosine kinase receptor-3 gene (FLT3-ITD) mutation have poor prognoses and are often treated with allogeneic hematopoietic stem cell transplantation (HSCT). Sorafenib, an inhibitor of multiple kinases including FLT3, has shown promising activity in FLT3-ITD-positive AML. We treated 16 patients with FLT3-ITD-positive AML who relapsed after HSCT with sorafenib alone (n = 8) or in combination with cytotoxic chemotherapy (n = 8). The number of circulating blasts decreased in 80% of cases, but none of the patients achieved complete remission (CR); 3 achieved partial remission. Two patients were bridged to a second transplantation but both relapsed within 3 months of the transplantation. Median overall survival (OS) was 83 days, with none surviving more than a year. Sorafenib is not effective in the treatment of FLT3-ITD-positive AML relapsing after HSCT. Preventive strategies after HSCT may be more suitable for these high-risk patients.

Ex Vivo T Cell–Depleted versus Unmodified Allografts in Patients with Acute Myeloid Leukemia in First Complete Remission

This study was conducted to retrospectively compare the clinical outcomes after transplantation of T cell-depleted (TCD) and unmodified allografts in patients with acute myeloid leukemia (AML) in first complete remission (CR1). Patients received TCD grafts at Memorial Sloan-Kettering Cancer Center (MSKCC, N = 115) between 2001 and 2010 using the following preparative regimens: hyperfractionated total body irradiation (HFTBI)+thiotepa+fludarabine; HFTBI+thiotepa+cyclophosphamide; or i.v. busulfan+melphalan+fludarabine. TCD was performed by 1 of 2 immunomagnetic CD34(+) cell selection methods for peripheral blood grafts or by soybean lectin agglutination followed by sheep red blood cell-rosette depletion for bone marrow grafts. No additional graft-versus-host disease (GVHD) prophylaxis was administered. Patients received unmodified grafts at M.D. Anderson Cancer Center (MDACC, N = 181) after conditioning with busulfan+fludarabine and GVHD prophylaxis with tacrolimus+mini-methotrexate. Patients with unrelated or human leukocyte antigen-mismatched donors received anti-thymocyte globulin (ATG) at both centers, with some recipients of matched related donor TCD transplants also receiving ATG, depending upon the preparative regimen. TCD graft recipients were more likely to be older, receive a mismatched transplant, and have peripheral blood used as the graft source. The incidences rates of grades 2 to 4 acute GVHD and chronic GVHD were significantly lower in the TCD graft group (5% versus 18%, and 13% versus 53%). Three-year relapse-free and overall survival rates were 58% and 57%, respectively, in recipients of TCD grafts, and 60% and 66% in recipients of unmodified grafts (P = not significant). Survival and relapse-free survival are similar after TCD and conventional transplants from related/unrelated donors in patients with AML in CR1, but TCD significantly reduces GVHD.

General and Virus-Specific Immune Cell Reconstitution after Double Cord Blood Transplantation.

Cord blood transplantation (CBT) is curative for many patients with hematologic malignancies but is associated with delayed immune recovery and an increased risk of viral infections compared with HLA-matched bone marrow or peripheral blood progenitor cell transplantation. In this study we evaluated the significance of lymphocyte recovery in 125 consecutive patients with hematologic malignancies who underwent double-unit CBT (DUCBT) with an antithymocyte globulin-containing regimen at our institution. A subset of 65 patients was prospectively evaluated for recovery of T, natural killer (NK), and B cells, and in 46 patients we also examined viral-specific T cell recovery against adenovirus, Epstein-Barr virus, cytomegalovirus, BK virus, respiratory syncytial virus, and influenza antigen. Our results indicate that in recipients of DUCBT, the day 30 absolute lymphocyte count is highly predictive of nonrelapse mortality and overall survival. Immune recovery post-DUCBT was characterized by prolonged CD8+ and CD4+ T lymphopenia associated with preferential expansion of B and NK cells. We also observed profound delays in quantitative and functional recovery of viral-specific CD4+ and CD8+ T cell responses for the first year post-CBT. Taken together, our data support efforts aimed at optimizing viral-specific T cell recovery to improve outcomes post-CBT.

Results of a 2-arm, phase 2 clinical trial using post-transplantation cyclophosphamide for the prevention of graft-versus-host disease in haploidentical donor and mismatched unrelated donor hematopoietic stem cell transplantation

High‐dose, post‐transplantation cyclophosphamide (PTCy) to prevent graft‐versus‐host disease (GVHD) has improved outcomes in haploidentical (HAPLO) stem cell transplantation (SCT). However, it remains unclear whether this strategy is effective in SCT from 1‐antigen human leukocyte antigen (HLA)‐mismatched unrelated donors (9/10 MUD) and how the outcomes of these patients compare with those of haploidentical transplantation recipients.

Age and Modified European LeukemiaNet Classification to Predict Transplant Outcomes: An Integrated Approach for Acute Myelogenous Leukemia Patients Undergoing Allogeneic Stem Cell Transplantation.

We evaluated the prognostic significance of a modified European LeukemiaNet (ELN) classification for patients with acute myelogenous leukemia (AML) undergoing hematopoietic stem cell transplantation (HSCT) while in first complete remission (CR1). We analyzed 464 AML patients with matched related (n = 211, 45.5%), matched unrelated (n = 176, 37.9%), and mismatched donors (n = 77, 16.6%). Patients were classified into 4 modified ELN risk groups (favorable, intermediate-I, intermediate-II, and adverse) separately for 354 patients age < 60 years and 110 patients age ≥ 60 years. In this modified version of ELN classification, patients with normal cytogenetic were classified by FLT3-ITD mutational status: favorable risk if FLT3-ITDwild and intermediate-I if FLT3-ITDmut. The best outcomes occurred in the ELN favorable and intermediate-II groups in younger AML patients and in the favorable and intermediate-I groups in older AML patients. Older AML patients had worse transplant outcomes within each modified ELN risk group except intermediate-I when compared with younger patients; leukemia-free survival at 3 years was 67.8% versus 49.8% in favorable, 53.4% versus 50.7% in intermediate-I, 65.7% versus 20.2% in intermediate-II, and 44.6% versus 23.8% in adverse group younger and older patients, respectively. Among lesion-specific abnormalities, del5q/-5 and abnl(17p) had the worse transplant outcomes, with 3-year leukemia-free survival rates of 18.4% and 20% in younger CR1 patients. In conclusion, the modified ELN prognostic classification developed for chemotherapy outcomes also identifies prognostic groups for HSCT, which is useful for a selection of patients for post-transplant strategies to improve outcomes.

Can a female donor for a male recipient decrease the relapse rate for patients with acute myeloid leukemia treated with allogeneic hematopoietic stem cell transplantation

The mismatched minor histocompatibility antigens present on Y chromosome (H-Y) in male recipients receiving stem cells from female donors may contribute to the graft-versus-leukemia effect and results in a reduced relapse rate, especially in patients with high-risk disease. We retrospectively compared the outcomes of male patients with acute myeloid leukemia who received an allogeneic hematopoietic stem cell transplant (HSCT) from female donors (F-M) (174 patients) versus other gender combinations (667 patients). Median age was 50 years (range, 18 to 74 years). For the whole group, the 1-year cumulative incidence of relapse was significantly lower in F-M group (34.1% versus 41.3%, P = .044), whereas nonrelapse mortality (NRM) was higher (23.2% versus 15.7%, P = .004). For patients younger than 50 years beyond first complete remission, the F-M group was associated with lower relapse rate (42.5% versus 55.2%, P = .045) whereas NRM was not significantly different (35.8% versus 25.5%, P = .141). Although survival was not significantly improved, transplantation from a female donor for male recipient was associated with a lower relapse rate. When relapse is the most common concern for treatment failure, especially for younger patients, a female donor for a male recipient might be beneficial to decrease relapse rate after transplantation. Future studies are needed to explore how the H-Y mismatch may improve survival after transplantation.

Pre-transplantation minimal residual disease with cytogenetic and molecular diagnostic features improves risk stratification in acute myeloid leukemia

Our aim was to improve outcome prediction after allogeneic hematopoietic stem cell transplantation in acute myeloid leukemia by combining cytogenetic and molecular data at diagnosis with minimal residual disease assessment by multicolor flow-cytometry at transplantation. Patients with acute myeloid leukemia in first complete remission in whom minimal residual disease was assessed at transplantation were included and categorized according to the European LeukemiaNet classification. The primary outcome was 1-year relapse incidence after transplantation. Of 152 patients eligible, 48 had minimal residual disease at the time of their transplant. Minimal residual disease-positive patients were older, required more therapy to achieve first remission, were more likely to have incomplete recovery of blood counts and had more adverse risk features by cytogenetics. Relapse incidence at 1 year was higher in patients with minimal residual disease (32.6% versus 14.4%, P=0.002). Leukemia-free survival (43.6% versus 64%, P=0.007) and overall survival (48.8% versus 66.9%, P=0.008) rates were also inferior in patients with minimal residual disease. In multivariable analysis, minimal residual disease status at transplantation independently predicted 1-year relapse incidence, identifying a subgroup of intermediate-risk patients, according to the European LeukemiaNet classification, with a particularly poor outcome. Assessment of minimal residual disease at transplantation in combination with cytogenetic and molecular findings provides powerful independent prognostic information in acute myeloid leukemia, lending support to the incorporation of minimal residual disease detection to refine risk stratification and develop a more individualized approach during hematopoietic stem cell transplantation.

Phase 1 clinical trial using mbIL21 ex-vivo expanded donor-derived NK cells after haploidentical transplantation

Relapse has emerged as the most important cause of treatment failure after allogeneic hematopoietic stem cell transplantation (HSCT). To test the hypothesis that natural killer (NK) cells can decrease the risk of leukemia relapse, we initiated a phase 1 dose-escalation study of membrane-bound interleukin 21 (mbIL21) expanded donor NK cells infused before and after haploidentical HSCT for high-risk myeloid malignancies. The goals were to determine the safety, feasibility, and maximum tolerated dose. Patients received a melphalan-based reduced-intensity conditioning regimen and posttransplant cyclophosphamide-based graft-versus-host disease (GVHD) prophylaxis. NK cells were infused on days -2, +7, and +28 posttransplant. All NK expansions achieved the required cell number, and 11 of 13 patients enrolled received all 3 planned NK-cell doses (1 × 105/kg to 1 × 108/kg per dose). No infusional reactions or dose-limiting toxicities occurred. All patients engrafted with donor cells. Seven patients (54%) developed grade 1-2 acute GVHD (aGVHD), none developed grade 3-4 aGVHD or chronic GVHD, and a low incidence of viral complications was observed. One patient died of nonrelapse mortality; 1 patient relapsed. All others were alive and in remission at last follow-up (median, 14.7 months). NK-cell reconstitution was quantitatively, phenotypically, and functionally superior compared with a similar group of patients not receiving NK cells. In conclusion, this trial demonstrated production feasibility and safety of infusing high doses of ex vivo-expanded NK cells after haploidentical HSCT without adverse effects, increased GVHD, or higher mortality, and was associated with significantly improved NK-cell number and function, lower viral infections, and low relapse rate posttransplant.