Response of factor X deficiency to darutumumab in the treatment of AL amyloidosis: a novel finding.

We report a case of progressive light-chain amyloidosis (otherwise known as AL amyloidosis) with acquired factor X (aFX) deficiency with a complete haematological response and rapid normalisation of FX levels following daratumumab monotherapy. To our knowledge, this is the first case report documenting successful treatment with daratumumab of aFX deficiency secondary to AL amyloidosis. The patient responded well to this therapy, with excellent symptomatic and quality of life improvements as well as a reduction in bleeding manifestations. This case highlights the value in considering daratumumab treatment when AL amyloidosis is complicated by FX deficiency.

Acquired Factor X Deficiency in Patients With Primary Light Chain Amyloidosis.

Acquired factor X (FX) deficiency is a rare but serious complication of primary amyloidosis, presumably caused by the binding of amyloid proteins to the clotting factors. The prolonged prothrombin time, partial thromboplastin time, and low FX level, which are correctable by mixing study, are the disease hallmarks. An immediate goal of care is to stop bleeding. Clotting factor replacement requires close monitoring of coagulogram and FX levels due to varying FX clearance among patients. High-purity FX is currently approved for hereditary FX deficiency and has been successfully used in some acquired FX deficiency cases. Ongoing bleeding risk complicates the treatment decision. Novel therapies yielding rapid and deep response reduce amyloid protein production and improve long-term outcome.

Cutaneous adverse event associated with vemurafenib in a 3-year-old pediatric patient with BRAF mutation-positive metastatic melanoma and factor X deficiency.

Malignant melanoma is very rare in childhood. The approach to diagnosis and treatment in children has been adopted from adult guidelines. Vemurafenib is indicated in adults with BRAF V600 mutation-positive stage IIIc/IV melanoma and causes cutaneous adverse events. We report on a 3-year-old child with recurrent, metastatic (bone) BRAF mutation-positive melanoma. He also had severe factor X deficiency. Four days after vemurafenib treatment, bilateral palpebral edema and violet-colored hyperpigmentation were observed. There was no objective response to vemurafenib; however, bone pain regressed slightly. Our patient is the youngest patient who received vemurafenib for BRAF V600 mutation-positive metastatic melanoma in the literature.

Plasma-derived human factor X concentrate for on-demand and perioperative treatment in factor X-deficient patients: pharmacology, pharmacokinetics, efficacy, and safety.

INTRODUCTION: Hereditary factor X (FX) deficiency is a rare autosomal recessive bleeding disorder characterized mainly by mild-to-severe bleeding into the mucous membranes, muscles or joints. Previously, treatment options for hereditary FX deficiency were limited mostly to products that may not specify FX content (i.e. fresh frozen plasma and prothrombin complex concentrates) and that have associated safety concerns. To meet the need for a single-factor replacement therapy specifically for use in FX-deficient patients, a high-purity, high-potency, human plasma-derived FX concentrate (pdFX; Coagadex®; Bio Products Laboratory, Elstree, UK) has been developed and approved for treatment of perioperative bleeding and on-demand treatment in FX-deficient patients. Areas covered: The pharmacology, efficacy, and safety of pdFX are discussed, with a review of preclinical studies and clinical trial data that led to regulatory approval of pdFX in the United States and Europe. Expert opinion: As the first single-factor replacement therapy indicated for hereditary FX deficiency, pdFX is a safe and efficacious treatment option in patients aged ≥12 years with hereditary FX deficiency. Clinical studies of pdFX provide a dosing regimen for use in cases of bleeding episodes, surgery, and prophylaxis. Further studies are ongoing regarding use of pdFX long term and in patients aged ≤12 years.

Experience of a new high-purity factor X concentrate in subjects with hereditary factor X deficiency undergoing surgery.

INTRODUCTION: Maintaining haemostasis in surgery is challenging for hereditary rare bleeding disorders in which multi-coagulation-factor concentrates are the only therapeutic option. Hereditary factor X (FX) deficiency affects 1:500 000 to 1:1 000 000 individuals, and no specific replacement FX concentrate has been available. A high-purity, plasma-derived FX concentrate (pdFX) has been developed for patients with hereditary FX deficiency. AIM: Our objective was to assess the safety and efficacy of pdFX in subjects with FX deficiency undergoing surgery. METHODS: Subjects with hereditary mild-to-severe FX deficiency (basal plasma FX activity [FX:C] <20 IU dL(-1) ) undergoing surgery received pdFX preoperatively to raise FX:C to 70-90 IU dL(-1) and postoperatively to maintain levels >50 IU dL(-1) until the subject was no longer at risk of bleeding due to surgery. Efficacy of pdFX was assessed by blood loss during surgery, requirement for blood transfusion, postoperative bleeding from the surgical or other sites, and changes in haemoglobin levels. Safety was assessed by adverse events (AEs), development of inhibitors, and clinically significant changes in laboratory parameters. RESULTS: Five subjects (aged 14-59 years) underwent seven surgical procedures (four major and three minor). Treatment duration was 1-15 days. For each procedure, pdFX treatment was assessed as "excellent" in preventing bleeding and achieving haemostasis. No blood transfusions were required, no AEs related to pdFX were observed, and no clinically significant trends were found in any laboratory parameters. CONCLUSION: These data demonstrate that pdFX is safe and effective as replacement therapy in five subjects with mild-to-severe FX deficiency undergoing surgery on seven occasions.

Intracranial Hemorrhage as the First Manifestation of Severe Congenital Factor X Deficiency in a 20-Month-Old Male: Case Report and Review of the Literature.

Factor X deficiency (FXD) is a rare bleeding disorder, which can result in severe bleeding symptoms such as intracranial hemorrhage (ICH). The most common bleeding symptoms are epistaxis and gum bleeding. ICH is reported in 9-26% of all patients with FXD, mostly during the first month of life. Here, we present a rare case of a male presenting with ICH at the age of 20 months as the first manifestation of FXD. Secondary prophylaxis with factor X substitution once weekly prevented further bleeding.

Importance of pharmacokinetic studies in the management of acquired factor X deficiency.

Up to 14% of individuals with systemic AL amyloidosis develop acquired factor X deficiency, which occurs due to adsorption of factor X onto amyloid fibrils. Although baseline factor X levels are not predictive of bleeding risk in these patients, serious hemorrhagic complications can occur, particularly during invasive procedures. Optimal management strategies to attenuate bleeding risk in these patients are unknown. We describe our experience in the management of acquired factor X deficiency, secondary to systemic AL amyloidosis, in a case series of three patients who received prothrombin complex concentrates (PCCs) for treatment and prevention of bleeding events. We performed a retrospective review extracting information on baseline demographics, laboratory data, pharmacokinetic (PK) studies, and clinically documented bleeding events. Our case series demonstrates that individuals with acquired factor X deficiency secondary to amyloidosis have variable laboratory and clinical responses to PCCs. This is likely due to distinct amyloid loads and fibril sequences, leading to different binding avidities for factor X. Our data emphasize the importance of performing PK testing prior to any invasive procedures to determine the dose and frequency interval to achieve adequate factor X levels for hemostasis, given the variable response between individuals.

Factor X inhibitor: a fulminant presentation and fatal course of a rare syndrome in a 59-year-old male.

Factor X inhibitors are rare. The few cases documented in the literature have occurred after viral prodromes, in association with cancer, or after exposure to antibiotics. Acquired factor X deficiencies are also rare and their etiology is largely unknown. We report a new case of a factor X inhibitor and review prior cases of both factor X inhibitors and non-amyloidosis-related acquired factor X deficiencies.

Prothrombin complex concentrate such as therapy and prophylaxis in factor X-deficient patient (Friuli variant).

BACKGROUND: Factor X (FX) deficiency is a serious, rare bleeding disorder, with 1 in 500 000 affected people. Hemorrhages, hematuria, epistaxis, and other bleeding complications are frequent. CASE REPORT: Now, we report a case of a well-known 77-year-old FX-deficient patient (Friuli variant, level <1%, mutation Pro(343)→Ser, exon VIII) with hypertension, chronic obstructive pulmonary disease (COPD), and chronic gastritis, admitted many times to hospital due to surgical complications after aortic abdominal aneurysm (AAA) repair. Use of prothrombin complex concentrate (PCC) such as hemostatic therapy during surgeries and prophylaxis after discharge is shown in this article. Three consecutive surgeries were considered. First, endoleak postendoprosthesis; second, AAA breakage; and third, planned surgery, a new endovascular prosthesis positioning and femur-femoral bypass. No adverse events due to PCC were found by local physicians. DISCUSSION: We discuss the methods commonly used in the treatment and prophylaxis of patients with FX deficiency to reduce hemorrhagic risk and to improve their quality of life. CONCLUSION: Waiting for specific therapeutic options for FX deficiency, currently, the best treatment is represented by PCC. Its correct use permits an improvement in life quality and a reduction in bleeding frequency in FX-deficient patients.

[A patient with AL amyloidosis and severe factor X deficiency has been in complete haematological remission with normal factor X activity for 7 years following high-dose chemotherapy. A case study and literature review]. / Pacientka s AL-amyloidózou a závazným deficitem faktoru X je po vysokodávkované chemoterapii jiz 7 let v kompletní hematologické remisi s normální aktivitou faktoru X. Popis prípadu a prehled literatury.

Disturbance of haemostasis and bleeding are rather frequent complications of AL amyloidosis. These are frequently caused by increased fragility of capillaries, thrombocyte function disorders and coagulation cascade defects. The most frequent coagulation disorder is decreased factor X activity. We describe a 34-year old female after hysterectomy for myomatous uterus and metrorhagia. Before the surgery, the attending physicians did not identify any pathological changes suggesting a need for further investigations or presence of AL amyloidosis. Post-surgery development was complicated by life-threatening diffuse haemorrhage. Extended investigations of coagulation cascade revealed reduction of factor X activity to 16%. Targeted histological examination of the resected uterus confirmed AL amyloid deposits consisting of kappa chains. The patient's bone marrow contained certain small level of multiplied kappa chains-expressing plasma cells (< 10%); monoclonal immunoglobulins IgG K and free kappa chains were identified in serum. At that time, the patient did not satisfy the then valid Durie-Salmon criteria for multiple myeloma and thus the patient was diagnosed with primary systemic AL amyloidosis. The patient's condition gradually improved following substitution therapy (Prothromplex, fresh frozen plasma and erythrocyte transfusion) and bleeding slowly ceased so that chemotherapy with VAD (vincristine, adriamycin and dexamethasone) was initiated 6 weeks after the surgery. A total of 8 chemotherapy cycles were administered and complete haematological remission was achieved after the 5th cycle. Administration of the 8 VAD chemotherapy cycles resulted in increased factor X activity; bleeding complications subsided completely, thereby decreasing the risk of life-threatening mucositis-associated haemorrhage. Consequently, tandem high-dose chemotherapy (melphalan 100 mg/m2) with autologous haematopoietic stem cells transplantation was added to the treatment plan. Treatment was completed at the beginning of 2003 and, from that time, the patient is on continuous maintenance therapy with interferon alpha. Seven years from the diagnosis and 6 years from the completion of treatment the patient is in complete haematological remission, with no signs of organic damage caused by AL amyloid and with normal factor X activity. Factor X activity increased at the time when complete haematological remission was achieved after 8 cycles of VAD chemotherapy to 42%, it reached 68% the second year following high-dose chemotherapy, 77% after 5 years and 85% after 7 years. We had considered administration of high-dose chemotherapy in the standard regimen, i.e. following 4 cycles of VAD chemotherapy, as too high risk in the described young female patient. Therefore, we administered 8 cycles of conventional chemotherapy and only after complete haematological remission and partial organ response (factor X activity increased to 42%) were achieved, we added tandem high-dose chemotherapy to the treatment. We thus achieved long-term (7-years so far) complete haematological and organ remission. Increase in factor X activity is explicit over the entire 7-year observational period. We recommend starting treatment of high-risk transplant patients with AL amyloidosis with traditional chemotherapy regimen and, in case of positive haematological and organ treatment response, we recommend re-examination of potential benefits and risks of high-dose chemotherapy with autologous transplantation.

Diagnosis and treatment of inherited factor X deficiency.

Factor X is a vitamin K-dependent, liver-produced serine protease that serves a pivotal role in coagulation as the first enzyme in the common pathway to fibrin formation. Inherited factor X deficiency is a rare autosomal recessive bleeding disorder that is estimated to occur in 1:1,000,000 individuals up to 1:500 carriers. Several international registries of FX-deficient patients have greatly expanded the knowledge of clinical phenotype. A proposed classification of severity is based on FX:C activity measurements: an FX:C measurement <1% is severe, an FX:C measurement of 1-5% is moderate and an FX:C measurement of 6-10% is mild. Levels above 20% are infrequently associated with bleeding and heterozygotes are usually asymptomatic. Among patients with FX:C levels <10%, unlike moderate or severe haemophilia A and B, mucocutaneous bleeding symptoms such as epistaxis and menorrhagia occur in the majority. In addition, patients with moderate-severe deficiency may have symptoms similar to that of haemophilia A and B, including haemarthrosis, intracranial haemorrhage, and gastrointestinal bleeding. Genotype characterization may offer important clues about clinical prognosis. More than 80 mutations of the F10 gene have been identified, most of which are missense mutations. There is no specific FX replacement product yet readily available, but fresh frozen plasma and prothrombin complex concentrates can be used for treatment of bleeding symptoms and preparation for surgery.

Spontaneous major bleeding in acquired factor X deficiency secondary to AL-amyloidosis.

Abnormal bleeding may be seen in up to a third of patients with amyloidosis. Factor X deficiency is the commonest acquired coagulopathy in amyloidosis. While mild intracutaneous bleeding is common, spontaneous life-threatening haemorrhage is rare. We report a case of acquired FX deficiency due to amyloid light chain (AL)-amyloidosis presenting with spontaneous retroperitoneal bleeding. The diagnostic and management issues in this patient are discussed.

Successful treatment of systemic amyloidosis with hepatic involvement and factor X deficiency by high dose melphalan chemotherapy and autologous stem cell reinfusion.

Systemic amyloidosis with hepatic involvement is a rare disorder, which is characterized by the deposits of amyloid fibrils in the liver. The prognosis is poor and the median survival is 13 months. Bleeding problems resulting from coagulopathy frequently complicates systemic amyloidosis. We present two patients with a severe factor X deficiency and hepatomegaly as the presenting abnormalities of systemic amyloidosis. One of the patients was treated with high dose melphalan chemotherapy and autologous stem cell reinfusion, resulting in a normalization of the liver enzyme tests and the factor X level. The diagnosis and treatment of systemic amyloidosis with hepatic involvement and the management of the multifactorial coagulopathy in these cases is discussed.

Factor X deficiency.

Factor X is one of the vitamin K-dependent serine proteases. It plays a crucial role in the coagulation cascade, as the first enzyme in the common pathway of thrombus formation. The gene for factor X maps to the long arm of chromosome 13, approximately 2.8 kb downstream of the factor VII gene. The gene consists of eight exons, each of which encodes a specific functional domain within the protein. Both the gene structure and the amino acid sequence show homology to other vitamin K-dependent clotting factors, suggesting their origin in a common ancestral protein. Factor X deficiency is one of the rarest of the inherited coagulation disorders. Inheritance is in an autosomal recessive manner. The clinical phenotype is of a variable bleeding tendency. Homozygous factor X deficiency has an incidence of 1:1,000,000 in the general population. Heterozygotes are often clinically asymptomatic. Acquired factor X deficiency is rare, but when it occurs it is usually in association with amyloidosis. Treatment of factor X deficiency involves replacement of the protein with either fresh frozen plasma or prothrombin complex concentrates, although the latter should be used with caution as infusion may be associated with an increased risk of thrombosis.

Recombinant human factor VIIa in the management of amyloid-associated factor X deficiency.

Factor X deficiency is an important complication of amyloidosis. It is associated with severe bleeding that is difficult to control with plasma or prothrombin complex concentrates. Splenectomy ameliorates the factor X deficiency, but achieving satisfactory haemostasis for this operation is problematic. We report that a new clotting concentrate, recombinant factor VIIa, readily controls bleeding and makes splenectomy feasible.