Experiences with recombinant FVIIa in the emergency treatment of patients with autoimmune thrombocytopenia: a review of the literature

Treatment of critical bleeding events in patients with immune thrombocytopenia: a protocol for a systematic review and meta-analysis

BACKGROUND

Critical bleeding events in adults and children with ITP are medical emergencies; however, evidence-based treatment protocols are lacking. Due to the severe thrombocytopenia, (typically platelet count less than 20 × 109/L), a critical bleed portends a high risk of death or disability. We plan to perform a systematic review and meta-analysis of treatments for critical bleeding in patients with ITP that will inform evidence-based recommendations.

METHODS

Literature searches will be conducted in four electronic databases: Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and PubMed. Eligible studies will be randomized controlled trials or observational studies that enrolled patients with ITP describing one or more interventions for the management of critical bleeding. Title and abstract screening, full-text screening, data extraction, and risk of bias evaluation will be conducted independently and in duplicate using Covidence and Excel. Outcomes will be pooled for meta-analysis where appropriate or summarized descriptively. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology will be used to evaluate the certainty of the evidence. Primary outcomes of interest will include frequency of critical bleeds, mortality and bleeding-related mortality, bleeding resolution, platelet count, and disability.

DISCUSSION

Evidence-based treatments for critical bleeding in patients with ITP are needed to improve patient outcomes and standardize care in the emergency setting.

SYSTEMATIC REVIEW REGISTRATION

CRD42020161206.

In vitro characterization of CT-001-a short-acting factor VIIa with enhanced prohemostatic activity

BACKGROUND

Traumatic injury and the associated acute bleeding are leading causes of death in people aged 1 to 44 years. Acute bleeding in pathological and surgical settings also represents a significant burden to the society. Yet there are no approved hemostatic drugs currently available. While clinically proven as an effective pro-coagulant, activated factor VII (FVIIa) use in acute bleeding has been hampered by unwanted thromboembolic events. Enhancing the ability of FVIIa to quickly stop a bleed and clear rapidly from circulation may yield an ideal molecule suitable for use in patients with acute bleeding.

OBJECTIVES

To address this need and the current liability of FVIIa, we produced a novel FVIIa molecule (CT-001) with enhanced potency and shortened plasma residence time by cell line engineering and FVIIa protein engineering for superior efficacy for acute bleeding and safety.

METHODS

To address safety, CT-001, a FVIIa protein with 4 desialylated N-glycans was generated to promote active recognition and clearance via the asialoglycoprotein receptor. To enhance potency, the gamma-carboxylated domain was modified with P10Q and K32E, which enhanced membrane binding.

RESULTS

Together, these changes significantly enhanced potency and clearance while retaining the ability to interact with the key hemostatic checkpoint proteins antithrombin and tissue factor pathway inhibitor.

CONCLUSIONS

These results demonstrate that a FVIIa molecule engineered to combine supra-physiological activity and shorter duration of action has the potential to overcome the current limitations of recombinant FVIIa to be a safe and effective approach to the treatment of acute bleeding.

[Emergency treatment of severe bleeding in immune thrombocytopenia]

Immune thrombozytopenia (ITP) is a rare acquired thrombocytopenia occurring in 2 to 4 persons per 100,000 per year. ITP is defined as a platelet count less than 100 G/l in patients in whom other causes of thrombocytopenia have been ruled out. Severe bleeding is rare but may constitute a life-threatening condition. Therapeutic options include platelet transfusions, glucocorticoids and intravenous immune globuline (IVIG). Emergency splenectomy has to be considered in otherwise untreatable bleeding. We present the case of a 65-year-old patient with chronic refractory ITP and finally fatal bleeding.

Chinese guidelines for treatment of adult primary immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is a bleeding disorder commonly encountered in clinical practice. The International Working Group (IWG) on ITP has published several landmark papers on terminology, definitions, outcome criteria, bleeding assessment, diagnosis, and management of ITP. The Chinese consensus reports for diagnosis and management of adult ITP have been updated to the 4th edition. Based on current consensus positions and new emerging clinical evidence, the thrombosis and hemostasis group of the Chinese Society of Hematology issued Chinese guidelines for management of adult ITP, which aim to provide evidence-based recommendations for clinical decision making.

Diagnosis and management of immune thrombocytopenia in childhood

Evidence-based medicine is growing in immune thrombocytopenia (ITP), but solid clinical data are still lacking in many areas. A majority of children has self-limited ITP, but chronic symptomatic ITP exists also in pediatrics. Management includes a watch-and-wait strategy for children with newly diagnosed ITP and no or mild bleeding, and immunoglobulins and corticosteroids, if more bleeding and mucous membrane involvement is present. Treatment endpoints differ in clinical research and in clinical practice. The requirement of platelet enhancing drugs needs to be better defined in guidelines. Second-line therapies for children are rarely required and include thrombopoietin-receptor agonists, rituximab, dexamethasone and immunosuppressants. Thrombopoietin-receptor agonists are successful in adult but also in pediatric ITP. The strategical position of splenectomy differs from that in adults. Although effective in children it is less frequently used because of its life-long cumulative risk of infectious diseases and a higher potential of spontaneous remission in ITP, providing a strong argument to defer splenectomy. The rarity of ITP makes clinical research expensive.

Peri-operative considerations in the patient with primary immune deficiency: a review

BACKGROUND

Patients with inherited immune deficiency diseases often require surgical procedures, and their immune defects may predispose them to surgical complications.

METHODS

A thorough review of pertinent literature and current practice guidelines on surgery in patients with immune deficiency.

RESULTS

Peri-operative infections are a key, but not a singular, consideration in managing patients with a primary immune deficiency. Bleeding diathesis, gastrointestinal complications, pulmonary complications, and poor incision healing may also be idiosyncratic features unique to particular immune deficiency diseases. Patients with complex genetic syndromes that include immune deficiency also may display non-immunologic abnormalities that are equally important to surgical care.

CONCLUSION

Greater awareness of primary immune deficiencies and a comprehensive evaluation of such patients in close consultation with an immunologist can minimize surgical complications and optimize patient outcomes.

Successful management of refractory immune thrombocytopenia associated with massive alveolar hemorrhage

Immune thrombocytopenia (ITP) is an acquired immune-mediated disease characterized by persistant thrombocytopenia. Onset of the disease and the clinical course is highly variable, but the disease typically has a benign course. Patients rarely develop serious life-threatening bleeding. Herein, a case with refractory ITP and massive alveolar hemorrhage who was successfully treated with a fast and sequential approach is presented for the first time.

In vitro evaluation of clot quality and stability in a model of severe thrombocytopenia: effect of fibrinogen, factor XIII and thrombin-activatable fibrinolysis inhibitor

BACKGROUND

The treatment options in severe thrombocytopenia (platelet count ≤20×10(9)/L) are limited. The aim of this study was to investigate ways of improving blood clotting and stability in reconstituted thrombocytopenia.

MATERIALS AND METHODS

Thrombocytopenia (platelets [16±4]×10(9)/L) was created by differential centrifugation of normal blood followed by reconstitution of whole blood which was subjected to clotting in a rotation thromboelastometer by CaCl2 and tissue factor, and to fibrinolysis by tissue plasminogen activator (tPA). In separate experiments, blood was diluted by 40% with TRIS/saline solution. Blood was treated with fibrinogen (fib), factor XIII (FXIII), and thrombin-activatable fibrinolysis inhibitor (TAFI).

RESULTS

The maximum clot firmness of thrombocytopenic blood was approximately 2-fold less than that of intact blood. Supplementation of blood with fib and FXIII improved clot formation. In the presence of tPA, among fib, FXIII and TAFI, only fib stimulated clot propagation whereas each of these agents increased clot strength. There was a synergistic effect when fib was added together with FXIII or TAFI. Fibrinolysis was inhibited by TAFI and to a greater extent by TAFI + FXIII. Fourty percent dilution of blood reduced clot strength and increased susceptibility to tPA. Clot strength was increased by the treatments in the following order: fib/FXIII/TAFI > fib/TAFI > fib > TAFI > FXIII. In the presence of tPA, TAFI and FXIII lysed the clots significantly more slowly. This effect was stronger when blood was treated with the combination of fib/FXIII/TAFI. Doubling the fib concentration, alone or together with other agents, did not improve clot strength or stability.

DISCUSSION

Augmentation of clot formation and anti-fibrinolysis by combining fib, FXIII and TAFI may be beneficial for the treatment of patients with severe thrombocytopenia especially when complicated by haemodilution following introduction of fluids to compensate for massive blood loss.

[Treatment of a pregnant patient after multiple trauma: rare combination with thrombotic thrombocytopenic purpura]

Multiple trauma during pregnancy is a relatively rare situation which poses a great challenge for the team in charge of treatment. A concomitant disease, such as thrombotic thrombocytopenic purpura (TTP) with thrombocytic coagulopathy increases the complexity of the treatment problems. This article describes the case of a 36-year-old pregnant woman referred to this hospital suffering from multiple trauma with severe liver rupture. Stabilization was achieved after an emergency Caesarean section and packing of the liver. Recurrent massive bleeding from the liver occurred after depacking and was treated successfully with recombinant factor VIIa. The concomitant TTP was treated by transfusion of fresh frozen plasma and corticosteroids. Rapid initiation of therapy was the goal to achieve hemostasis and prevent aggravation of the coagulation disorder and an unfavourable outcome despite severe thrombocytopenia.

Use of Recombinant Factor VIIa in a Pediatric Patient With Initial Presentation of Refractory Acute Immune Thrombocytopenic Purpura and Severe Bleeding

Severe bleeding in acute immune thrombocytopenic purpura (ITP) is rare but can cause significant complications to the patient. Here we report the case of a pediatric patient with acute ITP and hematuria refractory to anti-D immune globulin, high dose intravenous immunoglobulin G, and high dose steroids. Her hematuria was successfully treated with recombinant factor VIIa (rFVIIa). While further investigation on the use of rFVIIa in ITP is warranted, this case report contributes to the pediatric literature for its use during the course of an initial presentation of ITP with hemorrhagic complications.

Immune thrombocytopenic purpura: historical perspective, current status, recent advances and future directions

Immune thrombocytopenic purpura (ITP) has witnessed many changes and updates over the past decade. The definitions of disease subtypes, course and response to treatment have all been standardized recently. Consequent to the lack of an international consensus management guideline, wide variations exist in treatment practice. This is now being addressed to an extent by the much awaited ITP International Working Group 2010 recommendations. The pathophysiologic mechanisms have been unfolded at cellular, molecular and humoral levels. As a result, many recent advances have taken place in the management of this disorder. This review revisits the history of evolution of ITP, summarizes the current recommendations for management and lists the recent advances and future prospects in this field.

The American Society of Hematology 2011 evidence-based practice guideline for immune thrombocytopenia

Immune thrombocytopenia (ITP) is commonly encountered in clinical practice. In 1996 the American Society of Hematology published a landmark guidance paper designed to assist clinicians in the management of this disorder. Since 1996 there have been numerous advances in the management of both adult and pediatric ITP. These changes mandated an update in the guidelines. This guideline uses a rigorous, evidence-based approach to the location, interpretation, and presentation of the available evidence. We have endeavored to identify, abstract, and present all available methodologically rigorous data informing the treatment of ITP. We provide evidence-based treatment recommendations using the GRADE system in those areas in which such evidence exists. We do not provide evidence in those areas in which evidence is lacking, or is of lower quality--interested readers are referred to a number of recent, consensus-based recommendations for expert opinion in these clinical areas. Our review identified the need for additional studies in many key areas of the therapy of ITP such as comparative studies of "front-line" therapy for ITP, the management of serious bleeding in patients with ITP, and studies that will provide guidance about which therapy should be used as salvage therapy for patients after failure of a first-line intervention.

[Efficacy of recombinant activated factor VII in diffuse alveolar haemorrhage]

INTRODUCTION

Alveolar haemorrhage is a serious complication of a range of different pathologies. Published recent literature has reported only cases unresponsive to the usual treatment (steroids, transfusions, immunosuppressors and mechanical ventilation) as well as multiple secondary complications of these kinds of therapies. Recombinant activated factor VII (rF VIIa) is a new class of agent, which appears to be a successful adjunct therapy in the case of failure of conventional treatments.

OBSERVATIONS

We describe two cases of alveolar haemorrhage treated with rF VIIa. The first patient had leukaemia and the second had ANCA-associated granulomatous vasculitis. Both were admitted to the intensive care unit for mechanical ventilation with persistent diffuse alveolar haemorrhage that responded only to a single dose of rF VIIa (90 μg/kg).

DISCUSSION AND CONCLUSION

rF VIIa is a promising treatment for diffuse, persistent alveolar haemorrhage, with only a small dose required to be effective. Future studies are needed in order to establish a clear protocol for the administration of this novel agent.