Elotuzumab plus Pomalidomide and Dexamethasone for Multiple Myeloma.

BACKGROUND: The immunostimulatory monoclonal antibody elotuzumab plus lenalidomide and dexamethasone has been shown to be effective in patients with relapsed or refractory multiple myeloma. The immunomodulatory agent pomalidomide plus dexamethasone has been shown to be effective in patients with multiple myeloma that is refractory to lenalidomide and a proteasome inhibitor. METHODS: Patients with multiple myeloma that was refractory or relapsed and refractory to lenalidomide and a proteasome inhibitor were randomly assigned to receive elotuzumab plus pomalidomide and dexamethasone (elotuzumab group) or pomalidomide and dexamethasone alone (control group). The primary end point was investigator-assessed progression-free survival. RESULTS: A total of 117 patients were randomly assigned to the elotuzumab group (60 patients) or the control group (57 patients). After a minimum follow-up period of 9.1 months, the median progression-free survival was 10.3 months in the elotuzumab group and 4.7 months in the control group. The hazard ratio for disease progression or death in the elotuzumab group as compared with the control group was 0.54 (95% confidence interval [CI], 0.34 to 0.86; P=0.008). The overall response rate was 53% in the elotuzumab group as compared with 26% in the control group (odds ratio, 3.25; 95% CI, 1.49 to 7.11). The most common grade 3 or 4 adverse events were neutropenia (13% in the elotuzumab group vs. 27% in the control group), anemia (10% vs. 20%), and hyperglycemia (8% vs. 7%). A total of 65% of the patients in each group had infections. Infusion reactions occurred in 3 patients (5%) in the elotuzumab group. CONCLUSIONS: Among patients with multiple myeloma in whom treatment with lenalidomide and a proteasome inhibitor had failed, the risk of progression or death was significantly lower among those who received elotuzumab plus pomalidomide and dexamethasone than among those who received pomalidomide plus dexamethasone alone. (Funded by Bristol-Myers Squibb and AbbVie Biotherapeutics; ELOQUENT-3 ClinicalTrials.gov number, NCT02654132 .).

Hematopoietic stem cell function requires 12/15-lipoxygenase-dependent fatty acid metabolism.

Fatty acid metabolism governs multiple intracellular signaling pathways in many cell types, but its role in hematopoietic stem cells (HSCs) is largely unknown. Herein, we establish a critical role for 12/15-lipoxygenase (12/15-LOX)-mediated unsaturated fatty acid metabolism in HSC function. HSCs from 12/15-LOX-deficient mice are severely compromised in their capacity to reconstitute the hematopoietic compartment in competitive and serial reconstitution assays. Furthermore, we demonstrate that 12/15-LOX is required for the maintenance of long-term HSC quiescence and number. The defect in HSCs is cell-autonomous and associated with a selective reduction in 12/15-LOX-mediated generation of bioactive lipid mediators and reactive oxygen species and with a decrease in canonical Wnt signaling as measured by nuclear beta-catenin staining. These results have implications for development, aging, and transformation of the hematopoietic compartment.

Erythroid dysplasia, megaloblastic anemia, and impaired lymphopoiesis arising from mitochondrial dysfunction.

Recent reports describe hematopoietic abnormalities in mice with targeted instability of the mitochondrial genome. However, these abnormalities have not been fully described. We demonstrate that mutant animals develop an age-dependent, macrocytic anemia with abnormal erythroid maturation and megaloblastic changes, as well as profound defects in lymphopoiesis. Mice die of severe fatal anemia at 15 months of age. Bone-marrow transplantation studies demonstrate that these abnormalities are intrinsic to the hematopoietic compartment and dependent upon the age of donor hematopoietic stem cells. These abnormalities are phenotypically similar to those found in patients with refractory anemia, suggesting that, in some cases, the myelodysplastic syndromes are caused by abnormalities of mitochondrial function.

Considerations on the use of adjunct red blood cell exchange transfusion in the treatment of severe Plasmodium falciparum malaria.

BACKGROUND: Travelers returning to the United States from malaria-endemic areas are at increased risk of a potentially fatal infection from Plasmodium falciparum, which requires prompt and aggressive treatment. STUDY DESIGN AND METHODS: Described is a case of a 7-year-old boy who was infected by P. falciparum while in Africa and developed features of severe infection, including hyperparasitemia, altered neurologic status, and malarial hepatitis. RESULTS: A single automated erythrocytapheresis procedure reduced parasitemia from 14% to less than 1%. Along with intravenous quinidine, this reduced parasite level was maintained throughout the hospitalization and the patient recovered. CONCLUSION: Exchange transfusion (ET) is an effective adjunct therapy to reduce the parasite load in cases of severe P. falciparum malaria. When performed in certain defined settings, the benefits can outweigh the risks of the procedure. Discussed are the medical and technical considerations on the use of adjunctive ET for severe P. falciparum infection and a review of the literature of the use of adjunct ET in the treatment of severe P. falciparum malaria.

Elotuzumab plus lenalidomide and dexamethasone for newly diagnosed multiple myeloma: a randomized, open-label, phase 2 study in Japan.

Novel therapies are needed for patients with newly diagnosed multiple myeloma (NDMM). Elotuzumab plus lenalidomide and dexamethasone (ELd) is approved for the treatment of relapsed/refractory multiple myeloma (RRMM). This phase 2 study in Japan evaluated ELd vs lenalidomide and dexamethasone (Ld) in patients with NDMM who were ineligible for stem cell transplantation. Elotuzumab infusion was accelerated to 5 mL/min by dose 3, cycle 1, allowing most subsequent infusions to be completed within 1 h. The primary endpoint was overall response rate (ORR) in the ELd arm. Secondary endpoints were the difference in ORR between treatments, and progression-free survival (PFS). Patients were randomized to ELd (n = 40) or Ld (n = 42); median number of treatment cycles was 13 (ELd) and 12 (Ld). In the ELd arm, ORR was 88% [70% confidence interval (CI) 80-93]. The estimated difference in ORR between treatments was 13% (95% CI - 4, 30) in favor of ELd. Progression-free survival data were immature. Safety was consistent with previous findings of ELd in Japanese patients with RRMM. No infusion reactions occurred at the maximum rate of 5 mL/min, which was used in 89% of elotuzumab infusions. ELd may be an effective, well-tolerated frontline treatment for patients with NDMM ineligible for stem cell transplantation.

Alternative method to determine the hematocrit of red blood cell units: a potential use in the apheresis unit.

BACKGROUND: In automated erythrocytapheresis procedures, achieving the desired-end hematocrit (Hct) requires that the COBE Spectra (CaridianBCT) machine be programmed with the mean Hct of the replacement red blood cell (RBC) units. To determine unit Hct, data derived from quality control (QC) Hct data were utilized. However, if a unit volume is outside the quality control (QC) volume parameters, the unit is accessed to measure its Hct. In this study, 21 percent of all RBC units need to be accessed to determine the Hct, which affects 47.5 percent of patient's erythrocytapheresis procedures. Spiking the unit compromises its integrity and hastens the expiration time of the unit. Nurses must wait until the patient arrives to check units outside QC parameters, thereby delaying the start time of procedures. Even if sampled units are kept refrigerated, they cannot be returned to the blood bank inventory once spiked. The goal of this study was to determine if accurate Hct levels from RBC units could be obtained from a unique segment. STUDY DESIGN AND METHODS: To determine the centrifuged Hct, samples were prepared from the RBC units and compared to that of the unique segment. RESULTS: The Hct of the unique segment exceeded that of the RBC unit by a small (1.2% in AS-1 units, 0.92% in AS-3 units), but statistically significant amount. CONCLUSION: The Hct from unique RBC segments closely approximates that of the original RBC unit. Unique segments can be made that will maintain the integrity and shelf life of RBC units.

Differences in erythrocyte sedimentation rates using the Westergren method and a centrifugation method.

The erythrocyte sedimentation rate (ESR) is a nonspecific screening test to assess elevations of acute phase proteins that occur in various acute and chronic diseases. The recommended method is based on the Westergren method. Other technologies to measure ESR have been developed, including centrifugation-based methods. We compared a centrifugation method (ESR STAT PLUS, Hema Technologies, Lebanon, NJ) with the current Westergren method (Sediplast ESR system, Polymedco, Cortlandt Manor, NY) at 3 ESR levels (0-20, 21-60, and >60 mm/h) in a pediatric population and found correlation coefficients of r=0.63, r=0.83, and r=0.43 respectively. The centrifugation ESR exceeded the Westergren ESR by a small but significant amount in the 0-20 mm/h range, where most normal ranges fall. The 2 methods were also compared in blood samples from patients with sickle cell disease, who tend to have lower ESRs owing to impaired rouleau formation. In the sickle cell group (n=39; r=0.87), the centrifugation ESR consistently exceeded (97% of time) the Westergren ESR. This study identifies the differences in ESR results using 2 methods in general and specific pediatric populations.

Serologic results in >1000 patients with suspected heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia (HIT) can lead to life-threatening and limb-threatening thrombosis. HIT is thought to be initiated by the interaction of pathogenic antibodies toward a complex platelet factor 4 (PF4) and heparin (PF4:H), which can activate platelets and predispose to thrombosis. As such, the laboratory diagnosis of HIT includes antigenic and functional assays to detect antibodies directed at PF4:H complexes. We performed a retrospective analysis of 1017 consecutive samples tested by serotonin-release assay and by enzyme-linked immunosorbent assay (ELISA). Most samples showed no serologic evidence of HIT, whereas 4% to 5% of samples demonstrated both antigenic and functional serological evidence for HIT. Approximately 12% to 18% of samples showed immunologic evidence of anti-PF4:H antibodies but without functional evidence of serotonin release in vitro. Interestingly, a small minority of samples (0.7%) caused serotonin release but were negative in the ELISA. The results are presented using cutoff values established at our hospital and for the ELISA manufacturer. This study provides a pretest probability of the serologic results from an antigenic assay (ELISA) and a functional assay (serotonin-release assay) in patients clinically suspected of having HIT.

Ulocuplumab (BMS-936564 / MDX1338): a fully human anti-CXCR4 antibody induces cell death in chronic lymphocytic leukemia mediated through a reactive oxygen species-dependent pathway.

The CXCR4 receptor (Chemokine C-X-C motif receptor 4) is highly expressed in different hematological malignancies including chronic lymphocytic leukemia (CLL). The CXCR4 ligand (CXCL12) stimulates CXCR4 promoting cell survival and proliferation, and may contribute to the tropism of leukemia cells towards lymphoid tissues. Therefore, strategies targeting CXCR4 may constitute an effective therapeutic approach for CLL. To address that question, we studied the effect of Ulocuplumab (BMS-936564), a fully human IgG4 anti-CXCR4 antibody, using a stroma--CLL cells co-culture model. We found that Ulocuplumab (BMS-936564) inhibited CXCL12 mediated CXCR4 activation-migration of CLL cells at nanomolar concentrations. This effect was comparable to AMD3100 (Plerixafor--Mozobil), a small molecule CXCR4 inhibitor. However, Ulocuplumab (BMS-936564) but not AMD3100 induced apoptosis in CLL at nanomolar concentrations in the presence or absence of stromal cell support. This pro-apoptotic effect was independent of CLL high-risk prognostic markers, was associated with production of reactive oxygen species and did not require caspase activation. Overall, these findings are evidence that Ulocuplumab (BMS-936564) has biological activity in CLL, highlight the relevance of the CXCR4-CXCL12 pathway as a therapeutic target in CLL, and provide biological rationale for ongoing clinical trials in CLL and other hematological malignancies.

Multiplex RT-PCR for the detection of leukemia-associated translocations: validation and application to routine molecular diagnostic practice.

The aim of this study was to validate the application of a commercially available multiplex reverse transcription polymerase chain reaction (RT-PCR) assay [Hemavision-7 System] for the seven most common leukemia translocations for routine molecular diagnostic hematopathology practice. A total of 98 samples, comprising four groups, were evaluated: Group 1, 16 diagnostic samples molecularly positive by our existing laboratory-developed assays for PML-RARalpha/t (15;17) or BCR-ABL/t (9;22); Group 2, 51 diagnostic samples negative by our laboratory-developed assays for PML-RARalpha/t (15;17) or BCR-ABL/t (9;22); Group 3, 21 prospectively analyzed diagnostic cases, without prior molecular studies; and Group 4, 10 minimal residual disease (MRD) samples. Analysis of the two previously studied cohorts (Groups 1 and 2) confirmed the diagnostic sensitivity and specificity of the multiplex assay with regard to these two translocations. Additionally, however, in the "negative" Group (Group 2) the assay revealed three unanticipated translocations (CBFbeta-MYH11, BCR-ABL, and MLL-AF4), two of which were confirmed on cytogenetics. Analysis of the prospective cohort demonstrated that the assay was cost-effective and amenable to standard laboratory practice, with an identically sensitive MRD detection rate to that of our laboratory-developed tests. Virtually all of the results obtained were consistent with the phenotype and karyotype by conventional methods. This study illustrates the utility of a kit-based multiplex RT-PCR assay for the molecular diagnosis and monitoring of leukemias and reinforces the complementary roles of molecular testing and cytogenetics in diagnostic hematopathology.

Aggressive Epstein-Barr virus-associated, CD8+, CD30+, CD56+, surface CD3-, natural killer (NK)-like cytotoxic T-cell lymphoma.

We report an unusual case of aggressive natural killer (NK)-like cytotoxic T-cell lymphoma in a previously healthy immunocompetent West African male. He presented with a fever of unknown origin, subsequently developed erythematous skin nodules, generalized lymphadenopathy, and hepatosplenomegaly, and then died of multiple organ failure. A skin nodule and lymph node biopsy showed an infiltrate of pleomorphic atypical medium and large lymphoid cells with extensive necrosis and prominent apoptosis. Peripheral blood and ascites also harbored these cells, with cytology revealing irregular nuclear folding and basophilic cytoplasm, and some with azurophilic cytoplasmic granules. Flow cytometry and immunohistochemistry demonstrated the expression of CD2, CD7, CD8, CD30, CD56, and cytoplasmic but not surface CD3. In situ hybridization demonstrated Epstein-Barr virus transcripts. A monoclonal T-cell receptor gamma chain gene rearrangement was detected by polymerase chain reaction. This is the first reported case of an NK-like T-cell lymphoma with these unusual features, making precise classification difficult. Some features suggest an NK1.1 or NKT lymphocyte origin. Because the earliest clinical manifestation was splenomegaly and abnormal liver function, the normal cellular counterpart may be a distinct subset of NK1.1 cells normally present in hepatosplenic sinusoids. This tumor disseminated early and pursued a fulminant clinical course, thus emphasizing the importance of early recognition and diagnosis.

Practical considerations for planning a therapeutic apheresis procedure.

The general medicine and critical care services often care for patients that require therapeutic apheresis. Apheresis procedures are performed for various hematologic, neurological, renal, autoimmune, metabolic, and other indications. To facilitate a prompt start to the procedure, the clinical team must coordinate efforts with several services, including those that perform the apheresis procedure, establish venous access, and provide blood or replacement products, in addition to the pharmacy and clinical laboratory. Some of these tasks are performed typically by the clinical teams, while others are performed typically by the apheresis team. Presented and discussed are the indications for therapeutic apheresis, calculations for the ordering of blood products, and several important and practical details to consider, thus preventing delays in starting the apheresis procedure.

Thrombotic thrombocytopenic purpura and sickle cell crisis.

Described is a case of acute chest syndrome in a sickle-cell patient (hemoglobin SS) who also developed signs and symptoms of thrombotic thrombocytopenic purpura, including thrombocytopenia and hemolysis (anemia, elevated lactate dehydrogenase, presence of schistocytes, dark-colored plasma, and elevations in nucleated red blood cells). The ADAMTS13 activity level was normal. Discussed are the diagnosis and therapeutic management issues and the challenges of differentiating the vasoocclusive and hemolytic complications of sickling red blood cells from the thrombotic microangiopathy of thrombotic thrombocytopenic purpura.

Interferon regulatory factor-8-driven myeloid differentiation is regulated by 12/15-lipoxygenase-mediated redox signaling.

OBJECTIVE: Several transcription factors determine the cell fate decision between granulocytes and monocytes, but the upstream signal transduction pathways that govern myelopoiesis are largely unknown. Based on our observation of aberrant myeloid cell representation in hematopoietic tissues of 12/15-lipoxygenase (12/15-LOX)-deficient (Alox15) mice, we tested the hypothesis that polyunsaturated fatty acid metabolism regulates myelopoiesis. MATERIALS AND METHODS: Multicolor flow cytometric analysis and methylcellulose assays were used to compare myelopoiesis and the differentiative capacity of progenitors from Alox15 and wild-type mice. Furthermore, we elucidated the mechanism by which 12/15-LOX is involved in regulation of myelopoiesis. RESULTS: Granulopoiesis in Alox15 mice is increased while monopoiesis is reduced. Moreover, there is an accumulation of granulocyte-macrophage progenitors that exhibit defective differentiation. Mechanistically, we demonstrate that transcriptional activity of interferon regulatory factor-8 (Irf8), which regulates myelopoiesis, is impaired in Alox15 progenitors and bone marrow-derived macrophages due to loss of 12/15-LOX-mediated redox regulation of Irf8 nuclear accumulation. Restoration of redox signaling in Alox15 bone marrow cells and granulocyte-macrophage progenitors reversed the defect in myeloid differentiation. CONCLUSIONS: These data establish 12/15-LOX-mediated redox signaling as a novel regulator of myelopoiesis and Irf8.

An iron responsive element-like stem-loop regulates alpha-hemoglobin-stabilizing protein mRNA.

Hemoglobin production during erythropoiesis is mechanistically coupled to the acquisition and metabolism of iron. We discovered that iron regulates the expression of alpha-hemoglobin-stabilizing protein (AHSP), a molecular chaperone that binds and stabilizes free alpha-globin during hemoglobin synthesis. In primates, the 3'-untranslated region (UTR) of AHSP mRNA contains a nucleotide sequence resembling iron responsive elements (IREs), stem-loop structures that regulate gene expression post-transcriptionally by binding iron regulatory proteins (IRPs). The AHSP IRE-like stem-loop deviates from classical consensus sequences and binds IRPs poorly in electrophoretic mobility shift assays. However, in cytoplasmic extracts, AHSP mRNA co-immunoprecipitates with IRPs in a fashion that is dependent on the stem-loop structure and inhibited by iron. Moreover, this interaction enhances AHSP mRNA stability in erythroid and heterologous cells. Our findings demonstrate that IRPs can regulate mRNA expression through non-canonical IREs and extend the repertoire of known iron-regulated genes. In addition, we illustrate a new mechanism through which hemoglobin may be modulated according to iron status.

False-positive pregnancy test after passive transfusion of beta-human chorionic gonadotropin from donor red blood cells during erythrocytapheresis.

BACKGROUND: Patients transfused with blood products may passively receive soluble antibodies, proteins, and other analytes that persist during the collection, processing, and transfusion of the blood product. In this report, a female patient who received transfusion of five red blood cell (RBC) units during erythrocytapheresis later demonstrated an unexpected positive result in assays for the beta-subunit of human chorionic gonadotropin (bHCG), a screening test for pregnancy. The result caused postponement of an elective surgical procedure. A follow-up test 1 week later was negative. STUDY DESIGN AND METHODS: To investigate the possibility of passive transfusion of the hormone from a donor RBC unit, a sample from each of the units transfused was assayed for the level of bHCG. RESULTS: One of the 5 units transfused to the patient had a high level of bHCG. The observed bHCG level in the recipient was found to be comparable to the predicted level, given the donor's plasma bHCG level and accounting for the dilution factors in the preparation of the RBC unit and the erythrocytapheresis procedure and the in vivo t((1/2)) of the hormone. CONCLUSION: The donor, who was unaware of her pregnancy status at the time of donation, harbored a high bHCG level that caused the positive test result in the recipient patient's serum and urine. If an unexpected analyte or serology is detected in a recipient of a blood transfusion, it is important to consider the possibility of passive transfusion of the analyte.

Molecular biology of ADAMTS13 and diagnostic utility of ADAMTS13 proteolytic activity and inhibitor assays.

ADAMTS13, a reprolysin-like metalloprotease, limits platelet-rich thrombus formation in the small arteries by cleaving von Willebrand factor (vWF) at the Tyr1605-Met1606 peptide bond. Deficiency of plasma ADAMTS13 activity, due to either an inherited or an acquired etiology, may lead to a potentially lethal syndrome, thrombotic thrombocytopenic purpura (TTP). Molecular cloning and characterization of the ADAMTS13 gene have provided further insight into the structure-function relationships, biosynthesis, and regulation of the ADAMTS13 protease, in addition to understanding the pathogenesis of TTP and perhaps other thrombotic disorders. ADAMTS13 consists of a short propeptide, a typical reprolysin-like metalloprotease domain, followed by a disintegrin-like domain, first thrombospondin type 1 (TSP1) repeat, Cys-rich domain, and spacer domain. The carboxyl terminus of ADAMTS13 has seven more TSP1 repeats and two CUB domains. ADAMTS13 is synthesized mainly in hepatic stellate cells, but also in vascular endothelial cells. Recognition and cleavage of vWF require the proximal carboxyl terminal domains, but not the middle and distal carboxyl terminal domains. Cleavage of vWF appears to be modulated by shear force, binding to platelet or platelet glycoprotein-1balpha, heparin, inflammatory cytokine (interleukin-6), and chloride ion. At the site of thrombus formation, the ADAMTS13 may be inactivated by thrombin, plasmin, and factor Xa. Having a sensitive and specific assay for ADAMTS13 activity is not only critical to understand the basic biology of ADAMTS13 protease, but also to facilitate a more timely and accurate clinical diagnosis of TTP, and to initiate potentially life-saving plasma exchange therapy. Although many assays have been developed and tested for clinical applications, the fluorescent resonance energy transfer-vWF73 assay appears to be the simplest and most promising assay to date.