Peter Duggan

Unrelated donor BMT recipients given pretransplant low-dose antithymocyte globulin have outcomes equivalent to matched sibling BMT: A matched pair analysis

Fifty-seven patients receiving unrelated donor (UD) BMT were matched for disease and stage with 57 recipients of genotypically matched related donor (MRD) BMT. All UD recipients were matched serologically for A and B and by high resolution for DR and DQ antigens. All patients received CsA and ‘short course’ methotrexate with folinic acid. Unrelated donor BMT patients also received thymoglobulin 4.5 mg/kg (6 mg/kg if <30 kg) in divided doses over 3 days pretransplant. For UD and RD BMT, respectively, incidence of acute GVHD grade II–IV was 19 ± 6% vs 36 ± 8%, grade III–IV 10 ± 6% vs 18 ± 7%, chronic GVHD 44 ± 8% vs 51 ± 8%, non-relapse mortality 15 ± 5% vs 8 ± 4% at 100 days, 28 ± 8% vs 36 ± 7% at 3 years. At 3 years, relapse was 45 ± 7% vs 42 ± 7%, and disease-free survival 39 ± 7% vs 37 ± 7%. None of these differences are significant. Three-year overall survival was identical at 42 ± 7%. For 29 patients with low/intermediate risk leukemia, disease-free survival was 68 ± 10% after UD BMT vs 59 ± 9% for RD BMT recipients (P = NS). Corresponding figures for high risk patients were 14 ± 7% and 21 ± 8%, respectively. We conclude that UD BMT recipients matched as above and given pretransplant ATG have similar outcomes to recipients of MRD BMT using conventional drug prophylaxis. Unrelated donor BMT should be considered in any circumstance where MRD BMT is routine.

Bortezomib induced BRCAness sensitizes multiple myeloma cells to PARP inhibitors

Chromosomal instability is a defining feature of clonal myeloma plasma cells that results in the perpetual accumulation of genomic aberrations. In addition to its role in protein homeostasis, the ubiquitin-proteasome system is also involved in the regulation of DNA damage-repair proteins. In the present study, we show that proteasome inhibition induces a BRCAness state in myeloma cells (MM), with depletion of their nuclear pool of ubiquitin and abrogation of H2AX polyubiquitylation, an essential step for the recruitment of BRCA1 and RAD51 to the sites of DNA double-stranded breaks (DSBs) and the initiation of homologous recombination (HR)-mediated DNA repair. Inhibition of poly-ADP-ribose-polymerase 1 and 2 (PARP1/2) with ABT-888 induced transient DNA DSBs that were rapidly resolved and thus had no effect on viability of the MM cells. In contrast, cotreatment of MM cell lines and primary CD138(+) cells with bortezomib and ABT-888 resulted in the sustained accumulation of unrepaired DNA DSBs with persistence of unubiquitylated γH2AX foci, lack of recruitment of BRCA1 and RAD51, and ensuing MM-cell death. The heightened cytotoxicity of ABT-888 in combination with bortezomib compared with either drug alone was also confirmed in MM xenografts in SCID mice. Our studies indicate that bortezomib impairs HR in MM and results in a contextual synthetic lethality when combined with PARP inhibitors.

Integrin β7-mediated regulation of multiple myeloma cell adhesion, migration, and invasion.

Integrin-β7 (ITGB7) mRNA is detected in multiple myeloma (MM) cells and its presence is correlated with MAF gene activation. Although the involvement of several integrin family members in MM-stoma cell interaction is well documented, the specific biologic functions regulated by integrin-β7 in MM are largely unknown. Clinically, we have correlated integrin-β7 expression in MM with poor survival outcomes post autologous stem cell transplantation and postsalvage therapy with bortezomib. Functionally, we have found that shRNA-mediated silencing of ITGB7 reduces MM-cell adhesion to extra-cellular matrix elements (fibronectin, E-cadherin) and reverses cell-adhesion-mediated drug resistance (CAM-DR) sensitizing them to bortezomib and melphalan. In addition, ITGB7 silencing abrogated MM-cell transwell migration in response to SDF1α gradients, reduced vessel density in xenografted tumors, and altered MM cells in vivo homing into the BM. Mechanistically, ITGB7 knockdown inhibited focal adhesion kinase (FAK) and Src phosphorylation, Rac1 activation, and SUMOylation, reduced VEGF production in MM-BM stem cell cocultures and attenuated p65-NF-κB activity. Our findings support a role for integrin-β7 in MM-cell adhesion, migration, and BM homing, and pave the way for a novel therapeutic approach targeting this molecule.

Transplantation from Matched Siblings Using Once-Daily Intravenous Busulfan/Fludarabine with Thymoglobulin: A Myeloablative Regimen with Low Nonrelapse Mortality in All But Older Patients with High-Risk Disease

Two hundred patients received hematopoietic stem cell transplantation (HSCT) from matched sibling donors (MSD) after myeloablative conditioning including fludarabine (Flu) and once-daily intravenous busulfan (Bu). Thymoglobulin (TG) was added to methotexate (MTX) and cyclosporine (CsA) as graft-versus-host disease (GVHD) prophylaxis. For low-risk (acute leukemia CR1/CR2, CML CP1) patients projected 5-year nonrelapse mortality (NRM) and overall survival (OS) were 4% and 76% for those <or=45 years old (n = 54) and 6% and 83% for those >45 (n = 31). For high-risk (HR) patients NRM was 6% versus 27% (18% at 1 year) (P = .04) and OS 64% versus 37% (P = .47) in younger (n = 40) and older (n = 75) patients, respectively. To correct for imbalance in HR diagnoses each of 17 younger HR patients were matched with 2 older HR (OHR) patients by diagnosis and details of stage, and thereafter for other risk factors. For the younger HR and OHR patients, respectively, OS was 70% versus 37% (P = .02) and NRM 0 versus 34% (P = .02). When outcomes of OHR patients were compared with the other 3 groups combined NRM was 27% versus 5%, respectively (P = .002). Incidence of acute graft-versus-host disease (aGVHD) grade II-IV, aGVHD grade III-IV, and chronic GVHD (cGVHD) was 23% versus 10% (P = .02), 4% versus 2% (P = ns), and 66% versus 41% (P = .001), respectively. Nine of 14 nonrelapse deaths in the OHR group were related to GVHD or its treatment compared with 3 of 6 in all others (P value for GVHD related death = .01). Multivariate analysis of OS and DFS correcting for potentially confounding pretransplant factors identified only the OHR patients as having significantly increased risk (relative risk [RR] 3.32, confidence interval [CI] 1.71-6.47, P < .0001, and RR 3.32, CI 1.71-6.43, P < .0001, respectively). The effect of age on NRM is only apparent in HR patients, and is not explained by heterogeneity in diagnoses. Older HR patients experience more GVHD and more GVHD-related death than others, but NRM is no higher than reported with many nonmyeloablative regimens.

The Addition of 400 cGY Total Body Irradiation to a Regimen Incorporating Once-Daily Intravenous Busulfan, Fludarabine, and Antithymocyte Globulin Reduces Relapse Without Affecting Nonrelapse Mortality in Acute Myelogenous Leukemia

A combination of fludarabine (Flu) and daily i.v. busulfan (Bu) is well tolerated and effective in patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) for acute myelogenous leukemia (AML). The addition of rabbit antithymocyte globulin (ATG) may reduce morbidity and mortality from graft-versus-host disease (GVHD), but lead to increased relapse. To compensate for this effect, we added 400 cGy of total body irradiation (TBI) to the Flu/Bu regimen in 89 patients, and compared outcomes with those achieved in 90 patients who received the drug combination alone. Although nonrelapse mortality (NRM) at 3 years did not differ between the groups, the inclusion of TBI significantly reduced relapse (hazard ratio [HR] = 0.29; 95% confidence interval [CI] = 0.15-0.54; P = .0001). Consequently, both overall survival (OS; HR = 0.50; 95% CI = 0.3-0.84; P = .009) and disease-free survival (DFS; HR = 0.43; 95% CI = 0.26-0.72; P = .001) were improved with the inclusion of TBI. This study confirms the importance of regimen intensity in allogeneic HSCT for AML. The combination of daily i.v. Bu, Flu, 400 cGy TBI, and ATG provides a well-tolerated regimen with antileukemic activity in AML comparable to that of other, conventional myeloablative (MA) regimens.

Upfront thiotepa, busulfan, cyclophosphamide, and autologous stem cell transplantation for primary CNS lymphoma: a single centre experience

Abstract Treatment of primary central nervous system lymphoma (PCNSL) with high-dose methotrexate-based chemotherapy and whole-brain radiotherapy (WBRT) is associated with high rates of relapse and severe neurotoxicity. In an attempt to improve upon these poor results, we treated 21 patients with PCNSL aged 34–69 years (median 56) with high-dose thiotepa, busulfan, cyclophosphamide (TBC) and autologous stem cell transplant (ASCT) as part of front-line therapy, without WBRT. Patient characteristics included: Karnofsky performance status (KPS) <70% (n = 17), age >60 years (n = 8), deep brain involvement (n = 16). Treatment-induced neurotoxicity was not observed in any of these patients. Currently, 11 of 21 patients (52%) are alive and progression-free at a median follow-up of 60 (7–125) months post-ASCT. Causes of death included progressive PCNSL (n = 4), progressive systemic lymphoma (n = 1), early treatment-related mortality (TRM, n = 3) and two late deaths from pneumonia 3 years post-ASCT. All patients who died of TRM were over 60 years of age and had poor performance status. In conclusion, TBC/ASCT offers potential long-term progression-free survival without neurotoxicity when used as part of upfront therapy for PCNSL. However, efforts to reduce TRM through improved patient selection and possibly through decreased intensity of the TBC regimen for older or less fit patients are recommended.

Bone marrow staging of patients with non‐Hodgkin lymphoma by flow cytometry

Immunophenotypic analysis is an established tool in the diagnosis and classification of many hematolymphoid disorders; however, the role of flow cytometry (FC) in detecting bone marrow involvement during the staging of non‐Hodgkin lymphoma (NHL) has yet to be defined.

Predictive factors for long-term engraftment of autologous blood stem cells

Data from 170 consecutive patients aged 19–66 years (median age 46 years) who underwent unmanipulated autologous blood stem cell transplant (ASCT) were analyzed to determine if total CD34+ cells/kg infused, CD34+ subsets (CD34+41+, CD34+90+, CD34+33−, CD34+38−, CD34+38−DR−), peripheral blood CD34+ cell (PBCD34+) count on first apheresis day, or various clinical factors were associated with low blood counts 6 months post ASCT. Thirty-four patients were excluded from analysis either because of death (nu2009=u200917) or re-induction chemotherapy prior to 6 months post ASCT (nu2009=u200913), or because of lack of follow-up data (nu2009=u20094). Of the remaining 136 patients, 46% had low WBC (<4u2009×u2009109/l), 41% low platelets (<150u2009×u2009109/l), and 34% low hemoglobin (<120u2009g/l) at a median of 6 months following ASCT. By Spearmans rank correlation, both the total CD34+ cell dose/kg and the PBCD34+ count correlated with 6 month blood counts better than any subset of CD34+ cells or any clinical factor. The PBCD34+ count was overall a stronger predictor of 6 month blood counts than was the total CD34+ cells/kg infused. Both factors retained their significance in multivariate analysis, controlling for clinical factors. In conclusion, subsets of CD34+ cells and clinical factors are inferior to the total CD34+ cell dose/kg and PBCD34+ count in predicting 6 month blood counts following ASCT. Bone Marrow Transplantation (2000) 26, 1299–1304.

High incidence of post transplant lymphoproliferative disorder after antithymocyte globulin-based conditioning and ineffective prediction by day 28 EBV-specific T lymphocyte counts

The largest study on post-allogeneic hematopoietic cell transplant lymphoproliferative disorder (PTLD) epidemiology showed a cumulative incidence of 1.7% in patients receiving antithymocyte globulin (ATG). We had noted an apparently higher incidence in our transplant recipients whose conditioning included ATG. Therefore, we formally determined the incidence of PTLD through chart review. We also evaluated whether counts of EBV-specific T lymphocytes measured by cytokine flow cytometry could identify patients at risk of developing PTLD. Among 307 allogeneic transplant recipients, 25 (8.1%) developed PTLD. This was biopsy proven in 11 patients, and was fatal in seven patients. Patient age, EBV serostatus, donor type/match or GVHD did not influence PTLD risk significantly. Median onset of PTLD was 55 (range, 28–770) days post transplant. Day 28 EBV-specific T lymphocyte counts were not significantly different in 11 patients who developed PTLD and 31 non-PTLD patients matched for published risk factors for PTLD. In summary, when using conditioning with thymoglobulin 4.5u2009mg/kg, the incidence of PTLD is relatively high and cannot be predicted by day 28 cytokine flow cytometry-determined EBV-specific T lymphocyte counts. Thus, in this scenario PTLD prevention may be warranted, for example, using EBV DNAemia monitoring with preemptive therapy.

Development and Validation of a Test Dose Strategy for Once-Daily i.v. Busulfan: Importance of Fixed Infusion Rate Dosing

Intravenous (i.v.) busulfan (Bu) administered once daily in myeloablative transplant regimens is convenient, effective, and relatively well tolerated. Therapeutic drug monitoring is recommended as nonrelapse mortality increases when daily exposure, as determined by the area under the plasma concentration versus time curve (AUC), exceeds 6000 μM·min. We describe sequential studies to achieve accurate prediction of treatment doses of Bu based on the kinetics of a smaller test dose. A total of 335 patients with hematologic malignancies were given daily i.v. Bu 3.2 mg/kg × 4 and fludarabine 50 mg/m(2) × 5. Pharmacokinetic monitoring was conducted for both the test dose and first treatment dose of Bu (day -5). Three different test dose schedules were evaluated: 12 mg Bu administered over 20 minutes, 0.8 mg/kg over 3 hours, and 0.8 mg/kg infused at 80 mg/h. The 3.2 mg/kg treatment doses were infused over a fixed time of 3 hours for the first 2 test dose trials and at a fixed rate of 80 mg/h for the final protocol. All test dose infusions were on day -7. In the first 2xa0schedules, Bu administered over a fixed time had significantly higher clearance for the test dose compared with the treatment dose. However, when both the test and the treatment doses were administered at the same infusion rate, clearance of the drug between the 2 dosing days was equivalent. Predicted day -5 AUC (AUC(-5)) showed a high linear correlation (r(2) = 0.74) to the actual AUC(-5). The error of these predictions was <20% in 98% of patients and <10% in 80%. In 24 individuals, the test dose predicted an AUC >5500xa0μM·min; therefore, the first Bu treatment dose was reduced to a desired target AUC. All adjusted doses fell within 20% of the targeted exposure. We conclude that a test dose strategy for therapeutic drug monitoring of daily i.v. Bu is accurate if the test and treatment doses are infused at the same rate. This approach allows targeting of therapeutic doses of Bu to desired levels and the potential for improved safety and efficacy.