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To maintain lifelong production of blood cells, haematopoietic stem cells (HSCs) are tightly regulated by inherent programs and extrinsic regulatory signals received from their microenvironmental niche. Long-term repopulating HSCs reside [...]

Background: Dipeptidyl peptidase 4 (DPP-4; also known as CD26), a transmembrane receptor expressed on T cells, has a costimulatory function in activating T cells. In a mouse model, down-regulation of CD26 prevented graft-versus-host disease (GVHD) but preserved graft-versus-tumor effects. Whether inhibition of DPP-4 with sitagliptin may prevent acute GVHD after allogeneic stem-cell transplantation is not known.Methods: We conducted a two-stage, phase 2 clinical trial to test whether sitagliptin plus tacrolimus and sirolimus would reduce the incidence of grade II to IV acute GVHD from 30% to no more than 15% by day 100. Patients received myeloablative conditioning followed by mobilized peripheral-blood stem-cell transplants. Sitagliptin was given orally at a dose of 600 mg every 12 hours starting the day before transplantation until day 14 after transplantation.Results: A total of 36 patients who could be evaluated, with a median age of 46 years (range, 20 to 59), received transplants from matched related or unrelated donors. Acute GVHD occurred in 2 of 36 patients by day 100; the incidence of grade II to IV GVHD was 5% (95% confidence interval [CI], 1 to 16), and the incidence of grade III or IV GVHD was 3% (95% CI, 0 to 12). Nonrelapse mortality was zero at 1 year. The 1-year cumulative incidences of relapse and chronic GVHD were 26% (95% CI, 13 to 41) and 37% (95% CI, 22 to 53), respectively. GVHD-free, relapse-free survival was 46% (95% CI, 29 to 62) at 1 year. Toxic effects were similar to those seen in patients undergoing allogeneic stem-cell transplantation.Conclusions: In this nonrandomized trial, sitagliptin in combination with tacrolimus and sirolimus resulted in a low incidence of grade II to IV acute GVHD by day 100 after myeloablative allogeneic hematopoietic stem-cell transplantation. (Funded by the National Heart, Lung, and Blood Institute; ClinicalTrials.gov number, NCT02683525.). [ABSTRACT FROM AUTHOR]

Histoplasma capsulatum infection is a rare complication in the allogeneic stem cell transplant patients. Minimal guidance exists on how to appropriately manage histoplasmosis in these patients. We report a patient who developed Histoplasma pneumonia while receiving voriconazole prophylaxis at a therapeutic trough level. The patient experienced significant clinical improvement after initiation of itraconazole pharmacotherapy. We recommend a lower threshold for evaluation for histoplasmosis in allogeneic hematopoietic stem cell transplant recipients who live in endemic regions, regardless of their antifungal prophylactic regimen. [ABSTRACT FROM AUTHOR]

To maintain lifelong production of blood cells, haematopoietic stem cells (HSCs) are tightly regulated by inherent programs and extrinsic regulatory signals received from their microenvironmental niche. Long-term repopulating HSCs reside in several, perhaps overlapping, niches that produce regulatory molecules and signals necessary for homeostasis and for increased output after stress or injury. Despite considerable advances in the specific cellular or molecular mechanisms governing HSC-niche interactions, little is known about the regulatory function in the intact mammalian haematopoietic niche. Recently, we and others described a positive regulatory role for prostaglandin E2 (PGE2) on HSC function ex vivo. Here we show that inhibition of endogenous PGE2 by non-steroidal anti-inflammatory drug (NSAID) treatment in mice results in modest HSC egress from the bone marrow. Surprisingly, this was independent of the SDF-1-CXCR4 axis implicated in stem-cell migration. Stem and progenitor cells were found to have differing mechanisms of egress, with HSC transit to the periphery dependent on niche attenuation and reduction in the retentive molecule osteopontin. Haematopoietic grafts mobilized with NSAIDs had superior repopulating ability and long-term engraftment. Treatment of non-human primates and healthy human volunteers confirmed NSAID-mediated egress in other species. PGE2 receptor knockout mice demonstrated that progenitor expansion and stem/progenitor egress resulted from reduced E-prostanoid 4 (EP4) receptor signalling. These results not only uncover unique regulatory roles for EP4 signalling in HSC retention in the niche, but also define a rapidly translatable strategy to enhance transplantation therapeutically. [ABSTRACT FROM AUTHOR]

ENMD-2076 is a novel, orally-active molecule that has been shown to have significant activity against aurora and multiple receptor tyrosine kinases. We investigated the activity of ENMD-2076 against multiple myeloma (MM) cells in vitro and in vivo. ENMD-2076 showed significant cytotoxicity against MM cell lines and primary cells, with minimal cytotoxicity to haematopoietic progenitors. ENMD-2076 inhibited the phosphoinositide 3-kinase/AKT pathway and downregulated survivin and X-linked inhibitor of apoptosis as early as 6 h after treatment. With longer treatment (24–48 h), ENMD-2076 also inhibited aurora A and B kinases, and induced G2/M cell cycle arrest. In non-obese diabetic/severe combined immunodeficient mice implanted with H929 human plasmacytoma xenografts, oral treatment with ENMD-2076 (50, 100, 200 mg/kg per day) resulted in a dose-dependent inhibition of tumour growth. Immunohistochemical staining of excised tumours showed significant reduction in phospho-Histone 3 (pH3), Ki-67, and angiogenesis, and also a significant increase in cleaved caspase-3 at all dose levels compared to tumours from vehicle-treated mice. In addition, a significant reduction in p-FGFR3 was observed on Western blot. ENMD-2076 shows significant activity against MM cells in vitro and in vivo, and acts on several pathways important for myeloma cell growth and survival. These results provide preclinical rationale for clinical investigation of ENMD-2076 in MM. [ABSTRACT FROM AUTHOR]

DPP-IV is a homodimeric type II transmembrane receptor identical to the leucocyte surface antigen CD26. The interaction of CD26/DPP-IV on T cells with its ligand caveolin-1 on antigen-presenting cells (APC) enhances T cell activation, proliferation, and cytokine production. It also upregulates CD86 on APC resulting in co-stimulation. In a xenograft mouse model, reducing CD26 expression by a monoclonal antibody prevented aGVHD and preserved graft-versus-tumor effects (Hatano et al. BJH 2013). In a pilot trial testing sitagliptin for enhancement of cord blood engraftment, we observed a lower than expected rate of aGVHD (Farag et al. Stem Cell Dev 2013) and hypothesized that CD26/DPP-IV inhibition with sitagliptin may prevent aGVHD following allogeneic PBSC transplants. Conduct a prospective phase II trial to test if sitagliptin can reduce the rate of grade II-IV aGVHD by day +100 following myeloablative allogeneic PBSC transplants (ClinicalTrials.gov, NCT02683525). The primary endpoint was grade II-IV aGVHD by day +100. Patients received thiotepa (15 mg/kg) and cyclophosphamide (120 mg/kg), followed by G-CSF mobilized PBSC from matched related (6/6 HLA match) or unrelated (10/10 HLA match) donors. Sitagliptin (600 mg q12 hours) was given on days -1 to day +14, together with tacrolimus and sirolimus through day +100, then tapering until day +180. In a Simon two-stage design, <8 of a total of 36 patients developing grade II-IV aGVHD by day +100 would demonstrate a reduction of aGVHD from a historical rate of 30% to <15% with 80% power and type 1 error = 0.1. Thirty-six (17 M; 19 F) patients of median age 46 (20-59) years were enrolled. Patients had AML (n=19), ALL (n=9), MDS (n=4), and CML (n=4). Transplants were from matched related (13 patients) or unrelated (23 patients) donors. Acute GVHD occurred in 2 of 36 patients by day +100 (1 grade II; 1 grade IV), for cumulative incidences of 5.6% (95% confidence interval [CI], 0% - 13.2%) and 2.8% (95% CI, 0% - 8.2%) for grade II-IV aGVHD and grade III-IV aGVHD at day +100, respectively (Fig 1). An additional patient developed late-onset grade II aGVHD at day +140 following abrupt stopping of immunosuppression on day +100 for low donor chimerism in absence of relapse. Significant toxicities though day +30 included grades III-IV mucositis (n=15), acute kidney injury (4 with high tacrolimus levels, 1 sepsis), viral reactivation/infection (4 CMV, 2 BK, 1 EBV, 1 HHV6), and passenger lymphocyte syndrome (n=2). Non-relapse mortality was 0% at 12 months. With median follow-up of 699 (118-1312) days, the relapse-free survival was 77.2% (95% CI, 63.2% - 91.1%) and overall survival was 94.3% (95% CI, 86.7% - 100%) at 12 months (Fig 2a-b). CD26/DPP-IV inhibition with sitagliptin is well-tolerated and significantly reduced the rate of aGVHD by day +100 in patients undergoing myeloablative allogeneic PBSCT transplantation. [ABSTRACT FROM AUTHOR]

Objective: To investigate the degree and type of delays in performing diagnostic biopsies in medical patients with suspected malignancy.Design: Retrospective survey of clinical histories of patients referred between January 1985 and March 1989.Setting: Inner city teaching hospital internal medicine (non-oncologic) services.Patients: Patients with gastrointestinal and lung cancers, adenocarcinoma of unknown primary site, and lymphomas were referred as inpatients by internists. Two hundred fifty-five patients were eligible, and 177 were evaluable.Main Outcome Measures: The number, type, and results of tests done before and after biopsy were analyzed.Results: In 67% of patients the biopsied lesion was detected by the second day of evaluation; however, there was an 8- to 10-day delay before a biopsy was done. This delay was consistent across the four malignancy groups studied. Although logistic and other unavoidable delays occurred in 40% of the cases, in 60% delays could only be attributed to continued, frequently low yield, noninvasive tests. An average of 3.3 tests were made per patient, with only 24% leading to a definitive biopsy.Conclusion: Because of the performance of many other tests, a substantial delay exists in proceeding to biopsy during the diagnosis of cancer by internists. [ABSTRACT FROM AUTHOR]

Alternative anticoagulation in patients with heparin-induced thrombocytopenia (HIT) is often problematic. The relatively high cross-reactivity rate reported for the low-molecular-weight heparins (LMWH) has discouraged their use in this setting. This study has investigated the safety of using the LMWH Fragmin, based on a negative heparin-dependent platelet aggregation test using the latter, in patients with proven HIT. Fifty-three evaluable patients with clinical and laboratory evidence of HIT were evaluated for cross-reactivity with Fragmin using a Fragmin-dependent platelet aggregation test. In 20 of 38 patients who showed no in vitro cross-reactivity, Fragmin was substituted for unfractionated heparin. The outcome of these 20 patients was evaluated and compared to that of the remaining 33 patients, in whom anticoagulates were ceased or warfarin or Orgaran was used. Eighteen of 20 patients treated with Fragmin increased their platelet count by ≥50 x 109/l from a mean nadir of 57.9 ± 4.7 x 109/l within 2.8 ± 0.29 days following substitution of Fragmin for unfractionated heparin. Twenty-eight of the 33 remaining patients who did not receive Fragmin increased their platelet count by ≥50 x 109/l from a mean nadir of 53.0 ± 4.8 x 109/l within 3.0 ± 0.29 days. In seven patients (two treated with Fragmin), response could not be evaluated due to death within 36 h of cessation of heparin or discharge from hospital. The results indicate that in vitro cross-reactivity testing employing a heparin-dependent platelet aggregation assay can be safely used to select patients with HIT for further anticoagulation with LMWH. [ABSTRACT FROM AUTHOR]

Aim The risk of graft failure or graft-versus-host disease (GvHD) after Hematopoietic cell transplantation (HCT) strictly depends the degree of matching of histocompatibility antigens between the donor and recipient. In some cases due to rare HLA alleles or clinical emergency, it is difficult or even impossible to find a perfectly matched donor. HLA minor (allelic) mismatched (MM) donors (for example, B∗35:02 vs B∗35:05) have been shown to be an option for such patients. The goal of this study was to retrospectively analyze how class I minor MM HLA affect HCT outcomes. Methods The study population included 18 adult patients with a variety of hematological diseases who underwent HCT from 2001 through 2011 using unrelated donors with MM at class I HLA region. The control group included 55 patients transplanted within the same period of time who received 10/10 (HLA-A, -B, -C, -DR, -DQB1) matched HCTs. The groups were matched according to sex, age, diagnosis and pre-transplant protocol. High resolution HLA typing was performed using sequence based typing. The variables tested included total number of amino acid substitutions (AAS), locations of the AAS ( α helix or β strand), affected pockets (A, B, C, D, E, F), TCR or peptide binding sites, and dissimilarity score (DSS). These parameters were estimated using the HISTOCHECK computer algorithm. Statistical analysis comparing HLA matching parameters with the incidence of acute (a) and chronic (c) GvHD was done by ANOVA. Results All donor-recipient combinations were allele matched for DRB1 and DQB1 loci. Allelic MM transplants with a non-myeloablative preparative regimen was associated with a higher incidence of cGvHD (p = 0.009) Allelic MM at any class I locus was associated with increased risk of grade III-IV aGvHD (p = 0.0425). Variables predictive of any grade aGvHD were AAS in any HLA pocket but C (p < 0.030). DSS more than 10.0 was associated with increased risk for aGvHD and cGvHD (p = 0.0450) provided the AAS was in A, D, or F pockets. No significant association was found between MM and relapse, transplant-related mortality and overall survival. Conclusions AAS in peptide binding pockets in the setting of HLA class I MM donor-recipient combinations are at higher risk for GvHD and as such provide additional insight into donor search strategies. [ABSTRACT FROM AUTHOR]

Danger-associated molecular patterns (DAMPs) released during conditioning have been shown to amplify experimental GVHD. CD24 fusion protein (CD24Fc; OncoImmune), a glycoprotein linked to human IgG 1 Fc, binds to Siglec-10 to negatively regulate host response to DAMPs. We have reported that infusion of CD24Fc prior to HCT significantly decreased GVHD-related mortality in murine models of HCT (Toubai, Blood 2015 & Toubai, JCI Insight 2017). We hypothesized that enhancing Siglec10-CD24 interactions by administration of CD24Fc would prevent acute GVHD. A randomized, prospective, multi-site, placebo controlled phase 2a clinical trial was initiated to investigate safety of three dose levels of CD24Fc (or blinded placebo) plus standard GVHD prophylaxis with tacrolimus and methotrexate (MTX) in matched unrelated donors. T cell replete PBSC or BMT was infused. Randomization (3:1 ratio of CD24Fc:Placebo) was in 3 cohorts of 8 pts: 240mg single dose on D -1, 480mg single dose on D -1, and a 480mg, 240mg, and 240mg multiple dose regimen on D -1, 14 and 28, respectively. The primary endpoint was safety and determination of a recommended dose. Pts were followed for secondary endpoints of aGVHD, relapse and survival at D180. The trial enrolled 24 pts (CD24Fc, n=18; Placebo, n=6) with minimum follow up on one year (Table1). All planned dosages were administered without reaching an MTD. There were no infusion-related toxicities or DLTs. In placebo treated pts, there was one DLT resulting in death from pneumonia. Between groups there were no overall differences in AEs, although CD24Fc was associated with fewer days of severe (≥ Grade III) mucositis. There was no infection-related mortality related to CD24Fc treatment. The CD24Fc pts achieved neutrophil and platelet engraftment at a median of D 13 (12-23) and D 13 (9-23), respectively. PK studies demonstrated sustained drug levels through D 100 in the multi-dosing cohort. The incidence of grade II-IV GVHD was 39% (18-62%) and III-IV GVHD was 6% (95% CI 0-20%) at D 180 among CD24Fc treated pts. Grade 3 involvement of the lower-GI tract was observed in 1/18 pts, while the remainder of acute GVHD involved the upper GI tract or skin. All pts receiving treatment for GVHD experienced response. At D 180, relapse occurred in 2/18 pts, and OS was 100%. The endpoint of grade 3-4 GVHD-free survival (AGFS) was 94% at D 180 in pts receiving treatment with CD24Fc versus 50% in pts receiving placebo (HR 0.1; 90% CI 0.0-0.7). AGFS in contemporaneous case matched controls (n=68; CIBMTR) receiving myeloablative 8/8 HLA matched unrelated donor HCT with tacrolimus + MTX was 68% (95% CI: 56-78). In this translational phase 2a trial administration of CD24Fc was safe and tolerable. Additional investigations are required determine efficacy for improving AGFS after HCT. This trial represents the first attempt to prevent GVHD by inhibiting host response to DAMPs. [ABSTRACT FROM AUTHOR]

Tandem autologous stem cell transplantation (ASCT) improves long-term survival of platinum-refractory germ cell tumors (GCT) patients. Studies, predominantly in lymphoma, showed that CD34 + cell doses > 5.0 × 10 6 /kg/single transplant led to decreased resource utilization. Because most GCT patients have received prior cisplatin-based treatment, collecting >10 × 10 6 CD34 + cells/kg is challenging. We analyzed the effect of CD34 +  cell dose on resource utilization and outcome in 131 GCT patients, median age 29.5 years (range, 16 to 58), undergoing tandem ASCT. Of 262 individual transplants performed, 120 were performed as inpatient and 142 as planned outpatient. Overall, median CD34 + dose per transplant was 3.1 × 10 6 /kg (range, 0.8 to 16.0), with no significant difference between inpatient and outpatient transplants. Patients were divided into quartiles based on the CD34 cell dose infused: Q1, 0.8 to 1.9 × 10 6 /kg; Q2, 2.0 to 2.9 × 10 6 /kg; Q3, 3.0 to 4.1 × 10 6 /kg; and Q4, 4.2 to 16.0 × 10 6 /kg. For all patients higher CD34 + cell doses were associated with significantly shorter times to neutrophil ( P  <   .001) and platelet recovery ( P  <   .001). For inpatient transplants higher CD34 + doses were significantly associated with shorter length of hospital stay ( P  <   .001), fewer days of filgrastim ( P  <   .001), i.v. antibiotic ( P  = .012) and antifungal ( P  = .03) usage; and fewer RBC ( P  = .001) and platelet units transfused ( P  <   .001), resulting in overall lower cost of care ( P  < .001). Of the 142 planned outpatient transplants, 100 admissions were required for a median length of hospital stay of 7.0 days (range, 1 to 18). Although there was no significant difference in the rates of hospitalization between patients in different CD34 +  cell dose quartiles, a significant trend was observed for shorter hospitalization ( P  = .01) and fewer RBC ( P  = .002) and platelet ( P  = .005) transfusions with higher CD34 + cell dose quartile. Patients receiving CD34 +  cell doses in the lowest dose quartile (Q1) had significantly worse progression-free survival and overall survival compared with patients receiving higher CD34 +  cell doses. Overall, resource utilization, including cost of care, is significantly reduced when patients receive higher CD34 +  cell doses, indicating greater efforts to improve peripheral blood stem cell collection in this population are needed. [ABSTRACT FROM AUTHOR]

To maintain lifelong production of blood cells, haematopoietic stem cells (HSCs) are tightly regulated by inherent programs and extrinsic regulatory signals received from their microenvironmental niche. Long-term repopulating HSCs reside in several, perhaps overlapping, niches that produce regulatory molecules and signals necessary for homeostasis and for increased output after stress or injury. Despite considerable advances in the specific cellular or molecular mechanisms governing HSC-niche interactions, little is known about the regulatory function in the intact mammalian haematopoietic niche. Recently, we and others described a positive regulatory role for prostaglandin E2 (PGE2) on HSC function ex vivo. Here we show that inhibition of endogenous PGE2 by non-steroidal anti-inflammatory drug (NSAID) treatment in mice results in modest HSC egress from the bone marrow. Surprisingly, this was independent of the SDF-1-CXCR4 axis implicated in stem-cell migration. Stem and progenitor cells were found to have differing mechanisms of egress, with HSC transit to the periphery dependent on niche attenuation and reduction in the retentive molecule osteopontin. Haematopoietic grafts mobilized with NSAIDs had superior repopulating ability and long-term engraftment. Treatment of non-human primates and healthy human volunteers confirmed NSAID-mediated egress in other species. PGE2 receptor knockout mice demonstrated that progenitor expansion and stem/progenitor egress resulted from reduced E-prostanoid 4 (EP4) receptor signalling. These results not only uncover unique regulatory roles for EP4 signalling in HSC retention in the niche, but also define a rapidly translatable strategy to enhance transplantation therapeutically. [ABSTRACT FROM AUTHOR]