Publications by authors named "Loree Larratt"

Paroxysmal nocturnal hemoglobinuria (PNH) is caused by acquired gene mutations resulting in deficiency of glycosylphosphatidylinositol (GPI)-anchored complement regulatory proteins on the surface of blood cells, leading to terminal complement-mediated intravascular hemolysis and increased risk of major adverse vascular events (MAVEs). Using data from the International PNH Registry, this study investigated the relationship between the proportion of GPI-deficient granulocytes at PNH onset and (1) the risk for MAVEs (including thrombotic events [TEs]) and (2) the following parameters at last follow-up: high disease activity (HDA); lactate dehydrogenase (LDH) ratio; fatigue; abdominal pain; and rates of overall MAVEs and TEs. A total of 2813 patients untreated at enrollment were included and stratified by clone size at PNH disease onset (baseline).

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iLLUMINATE is a randomized, open-label phase III study of ibrutinib plus obinutuzumab (n=113) versus chlorambucil plus obinutuzumab (n=116) as first-line therapy for patients with chronic lymphocytic leukemia or small lymphocytic lymphoma. Eligible patients were aged ≥65 years, or <65 years with coexisting conditions. Patients received oral ibrutinib 420 mg once daily until disease progression or unacceptable toxicity or six cycles of oral chlorambucil, each in combination with six cycles of intravenous obinutuzumab.

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Eltrombopag has been shown to be noninferior to intravenous immunoglobulin (IVIG) for improving perioperative platelet counts in patients with immune thrombocytopenia (ITP) in a randomized trial; thus, cost is an important factor for treatment and policy decisions. We used patient-level data from the trial to conduct a cost-effectiveness analysis comparing perioperative eltrombopag 50 mg daily starting dose, with IVIG 1 or 2 g/kg (according to local practice) from a Canadian public health care payer's perspective over the observation period, from preoperative day 21 to postoperative day 28. Resource utilization data were obtained from the trial data (eltrombopag, n = 38; IVIG, n = 36), and unit costs were collected from the Ontario Schedule of Benefits, Ontario Drug Formulary, and secondary sources.

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Anti-CD20 antibody treatments, such as obinutuzumab, have been associated with infusion-related reactions (IRRs). In the phase 3 iLLUMINATE study of ibrutinib-obinutuzumab versus chlorambucil-obinutuzumab in first-line chronic lymphocytic leukemia/small lymphocytic lymphoma, IRRs were substantially reduced with ibrutinib-obinutuzumab versus chlorambucil-obinutuzumab. We prospectively analyzed inflammatory cytokines to evaluate the impact of ibrutinib on circulating cytokine levels following obinutuzumab infusion.

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Background: T cell exhaustion compromises antitumor immunity, and a sustained elevation of co-inhibitory receptors is a hallmark of T cell exhaustion in solid tumors. Similarly, upregulation of co-inhibitory receptors has been reported in T cells in hematological cancers such as chronic lymphocytic leukemia (CLL). However, the role of CD160, a glycosylphosphatidylinositol-anchored protein, as one of these co-inhibitory receptors has been contradictory in T cell function.

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Background: Patients with immune thrombocytopenia are at risk of bleeding during surgery, and intravenous immunoglobulin is commonly used to increase the platelet count. We aimed to establish whether perioperative eltrombopag was non-inferior to intravenous immunoglobulin.

Methods: We did a randomised, open-label trial in eight academic hospitals in Canada.

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Objectives: To evaluate the effects of eculizumab on transfusions and thrombotic events (TEs) in patients with and without prior history of transfusion in the International Paroxysmal Nocturnal Hemoglobinuria (PNH) Registry.

Methods: Registry patients enrolled on or before January 1, 2018, initiated on eculizumab no more than 12 months prior to enrollment, having known transfusion status for the 12 months before eculizumab initiation, and ≥12 months of Registry follow-up after eculizumab initiation, were included.

Results: Eculizumab treatment was associated with a 50% reduction in transfusions in patients with a transfusion history (10.

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The International Paroxysmal Nocturnal Hemoglobinuria (PNH) Registry (NCT01374360) was initiated to optimize patient management by collecting data regarding disease burden, progression, and clinical outcomes. Herein, we report updated baseline demographics, clinical characteristics, disease burden data, and observed trends regarding clone size in the largest cohort of Registry patients. Patients with available data as of July 2017 were stratified by glycosylphosphatidylinositol (GPI)-deficient granulocyte clone size (< 10%, ≥ 10%-< 50%, and ≥ 50%).

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Atopy is excessive production of IgE in response to allergens. We evaluated in patients undergoing allogeneic hematopoietic cell transplantation (HCT) the following hypotheses: (1) Atopy is "curable" in atopic patients receiving HCT from a nonatopic donor (D-R+), and (2) Atopy is transferable from atopic donors to nonatopic recipients (D+R-). Atopic patients with atopic donors (D+R+) and non-atopic patients with non-atopic donors (D-R-) served as controls.

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Background: Atypical hemolytic uremic syndrome (aHUS) is an extremely rare, heterogeneous disease of uncontrolled activation of the alternative complement pathway that is difficult to diagnose. We have evaluated the Canadian patients enrolled in the Global aHUS Registry to provide a Canadian perspective regarding the diagnosis and management of aHUS and the specific challenges faced.

Objective: To evaluate Canadian patients enrolled in the Global aHUS Registry to provide a Canadian perspective regarding the diagnosis and management of aHUS and the specific challenges faced.

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Background:  The Bridging ITP Trial is an open-label randomized trial designed to compare the oral thrombopoietin receptor agonist eltrombopag and intravenous immune globulin (IVIG) for patients with immune thrombocytopaenia (ITP) who require an increase in platelet count before elective surgery. Here, we report the study methods and rationale.

Methods:  We designed a multi-centre, non-inferiority randomized trial comparing daily oral eltrombopag starting 3 weeks pre-operatively, and IVIG administered 1 week pre-operatively for patients with ITP requiring a platelet count increase prior to surgery.

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Background: Both single-agent ibrutinib and chlorambucil plus obinutuzumab have shown superior efficacy to chlorambucil monotherapy and are standard first-line treatments in chronic lymphocytic leukaemia. We compared the efficacy of the combination of ibrutinib plus obinutuzumab with chlorambucil plus obinutuzumab in first-line chronic lymphocytic leukaemia or small lymphocytic lymphoma.

Methods: iLLUMINATE is a multicentre, randomised, open-label, phase 3 trial done at 74 academic and community hospitals in Australia, Canada, Israel, New Zealand, Russia, Turkey, the EU, and the USA in patients with previously untreated chronic lymphocytic leukaemia or small lymphocytic lymphoma, either aged 65 years or older or younger than 65 years with coexisting conditions.

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Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematologic disease characterized by intravascular hemolysis, thrombophilia, and marrow failure. Its phenotype is due to absent or reduced expression of GPI-linked complement regulators and subsequent sensitivity of hematopoietic cells to complement-mediated damage and lysis. Introduction of the terminal complement inhibitor eculizumab drastically improved outcomes in PNH patients; however, despite this improvement, there remain several challenges faced by PNH patients and physicians who care for them.

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This is a pivotal, multicenter, open-label study of moxetumomab pasudotox, a recombinant CD22-targeting immunotoxin, in hairy cell leukemia (HCL), a rare B cell malignancy with high CD22 expression. The study enrolled patients with relapsed/refractory HCL who had ≥2 prior systemic therapies, including ≥1 purine nucleoside analog. Patients received moxetumomab pasudotox 40 µg/kg intravenously on days 1, 3, and 5 every 28 days for ≤6 cycles.

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Rationale: Atypical hemolytic uremic syndrome, which has a high probability of chronic kidney disease, morbidity, and mortality, needs to be promptly recognized when patients present with microangiopathic hemolysis.

Presenting Concerns Of The Patient: Three patients present with laboratory parameters consistent with a thrombotic microangiopathy. With a suspected diagnosis of thrombotic thrombocytopenic purpura, steroids with plasmapheresis were initiated.

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Hairy cell leukemia is an uncommon hematologic malignancy characterized by pancytopenia and marked susceptibility to infection. Tremendous progress in the management of patients with this disease has resulted in high response rates and improved survival, yet relapse and an appropriate approach to re-treatment present continuing areas for research. The disease and its effective treatment are associated with immunosuppression.

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Most guidelines suggest that only the bone marrow aspirate (BMA) is necessary to assess residual disease following intensive chemotherapy for Acute Myeloid Leukemia (AML) with the bone marrow trephine biopsy (BMTB) recommended in cases of a poor quality BMA. We performed a retrospective study evaluating this in a cohort of patients receiving intensive chemotherapy for AML. Residual disease was assessed by morphological examination of the BMA and BMTB±immunohistochemistry.

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We conducted a retrospective study assessing FLAG (fludarabine, cytarabine, and granulocyte colony-stimulating factor) as first-line treatment in 56 newly diagnosed acute myeloid leukemia patients considered ineligible for anthracycline-based treatment due to advanced age, significant comorbidities, or pre-existing cardiac disease. The median age was 69 (21-80); 46% received FLAG for pre-existing cardiac disease and others due to age (32%), non-cardiac comorbidities (20%), or previous anthracycline exposure (2%). The induction mortality was 16% and, among evaluable patients, 48% achieved a complete remission after the first induction course with an additional patient achieving a remission after a second course for a total complete remission rate of 50%.

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In contrast to cyclosporine or methotrexate, rabbit antithymocyte globulin (ATG) used for graft-versus-host disease (GVHD) prophylaxis with myeloablative conditioning does not increase the risk of relapse after hematopoietic cell transplantation. The reason for this is unknown. We hypothesized that ATG at concentrations achieved with our standard ATG dose of 4.

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A man in his early 70s with a diagnosis of chronic lymphocytic leukemia and being treated with prednisone, fludarabine, cyclophosphamide, and rituximab presented with progressive multifocal neurologic decline. The patient died 2 months after the onset of this decline despite extensive clinical and laboratory investigation and a trial of methylprednisolone therapy. The approach to the immunosuppressed patient with progressive neurologic decline, neuropathologic findings, and final diagnosis are discussed.

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Hematopoietic cell transplant (HCT) recipients are immunocompromised and thus predisposed to infections. We set out to determine the deficiency of which immune cell subset(s) may predispose to postengraftment infections. We determined day 28, 56, 84, and 180 blood counts of multiple immune cell subsets in 219 allogeneic transplant recipients conditioned with busulfan, fludarabine, and Thymoglobulin.

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The glycolipid glycosylphosphatidylinositol anchor (GPI-A) plays an important role in lipid raft formation, which is required for proper expression on the cell surface of two inhibitors of the complement cascade, CD55 and CD59. The absence of these markers from the surface of blood cells, including erythrocytes, makes the cells susceptible to complement lysis, as seen in patients suffering from paroxysmal nocturnal haemoglobinuria (PNH). However, the explanation for why PNH-affected hematopoietic stem/progenitor cells (HSPCs) expand over time in BM is still unclear.

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The adhesion receptor CD44 plays an important role in the survival and retention of leukemic stem/progenitor cells (LSPC) within the bone marrow (BM) niche, as well as in the high relapse rates of acute myeloid leukemia (AML). Down-regulating CD44 could be clinically relevant not only for suppression of the deregulated function of LSPC but also in LSPC response to chemotherapeutic agents. Small interfering RNA (siRNA) delivery is a promising approach for AML treatment, and we recently reported effective siRNA delivery into difficult-to-transfect AML cell lines using lipid-substituted polyethylenimine/siRNA complexes (polymeric nanoparticles).

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Addition of rituximab (R) to fludarabine and cyclophosphamide (FC) has significantly improved patient outcomes in chronic lymphocytic leukemia (CLL). Whether baseline gene expression can identify patients who will benefit from immunochemotherapy over chemotherapy alone has not been determined. We assessed genome-wide expression of 300 pretreatment specimens from a subset of 552 patients in REACH, a study of FC or R-FC in relapsed CLL.

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