Factor X deficiency and pregnancy.

Factor X (FX) is a vitamin K-dependent enzyme, which acts as an important coagulation factor of coagulation cascade. FX deficiency is an autosomal recessive inherited disease and is often demonstrated in families with consanguity. Pregnancy in women with congenital FX deficiency has been associated with adverse fetal outcomes. We report a case of pregnancy in women with FX deficiency. The patient needed an immediate caesarean section at 38 weeks of gestation because of severe oligohydramnios and fetal distress. FX deficiency during pregnancy was effectively managed, leading to a positive outcome through the optimal utilisation of available resources.

Acute deep vein thrombosis with concurrent new diagnosis of AL-amyloid-induced factor X deficiency.

Acquired factor X (FX) deficiency is a rare but well-documented clinical feature of AL amyloidosis. Patients with FX deficiency can present with clinically significant bleeding diathesis due to the adsorption of circulating FX to amyloid fibrils. Here, we report an unusual case of a man in his 60s who presented with 6 months of intermittent bruising, labs demonstrating new FX deficiency, elevated free lambda light chains for underlying AL amyloidosis and concurrent new peroneal vein thrombosis. This is the first report of concurrent thrombotic complications in the setting of AL-amyloid-induced FX deficiency. We discuss the diagnostic and therapeutic conundrum of diagnosing AL amyloidosis with bruising as the leading clinical symptom and the management of acute deep vein thrombosis in the setting of FX deficiency.

Fitusiran reduces bleeding in factor X-deficient mice.

ABSTRACT: Factor X (FX) deficiency is a rare bleeding disorder manifesting a bleeding tendency caused by low FX activity levels. We aim to explore the use of fitusiran (an investigational small interfering RNA that silences antithrombin expression) to increase thrombin generation and the in vivo hemostatic potential under conditions of FX deficiency. We therefore developed a novel model of inducible FX deficiency, generating mice expressing <1% FX activity and antigen (f10low mice). Compared with control f10WT mice, f10low mice had sixfold and fourfold prolonged clotting times in prothrombin time and activated partial prothrombin time assays, respectively (P < .001). Thrombin generation was severely reduced, irrespective of whether tissue factor or factor XIa was used as an initiator. In vivo analysis revealed near-absent thrombus formation in a laser-induced vessel injury model. Furthermore, in 2 distinct bleeding models, f10low mice displayed an increased bleeding tendency compared with f10WT mice. In the tail-clip assay, blood loss was increased from 12 ± 16 µL to 590 ± 335 µL (P < .0001). In the saphenous vein puncture (SVP) model, the number of clots generated was reduced from 19 ± 5 clots every 30 minutes for f10WT mice to 2 ± 2 clots every 30 minutes (P < .0001) for f10low mice. In both models, bleeding was corrected upon infusion of purified FX. Treatment of f10low mice with fitusiran (2 × 10 mg/kg at 1 week interval) resulted in 17 ± 6% residual antithrombin activity and increased thrombin generation (fourfold and twofold to threefold increase in endogenous thrombin potential and thrombin peak, respectively). In the SVP model, the number of clots was increased to 8 ± 6 clots every 30 minutes (P = .0029). Altogether, we demonstrate that reduction in antithrombin levels is associated with improved hemostatic activity under conditions of FX deficiency.

Hereditary factor X deficiency in America survey: impact on quality of life and burden of disease in patients and caregivers.

Hereditary factor X deficiency (HFXD) is a rare bleeding disorder causing delayed haemostasis and potentially life-threatening bleeds. Patient/caregiver burden and diagnosis path have not been well characterized. THE AIM OF THIS STUDY WAS TO: describe the diagnosis path, disease burden, and HFXD impact on quality of life (QoL) in patients and caregivers.This was a prospective, cross-sectional, web-based survey of patients with HFXD and caregivers addressing the patient/caregiver experience, QoL, humanistic and unmet needs.Thirty patients and 38 caregivers completed the survey with mean ages 24.7 and 44.6 years, respectively. Mean age at diagnosis was 4.1 years. The diagnostic process was somewhat/very difficult for 23% of patients and 26% of caregivers. Approximately half (53%) received single factor replacement (SFR) as prophylaxis or on-demand. Most patients (71%) reported regular prophylaxis treatment. Over one-fourth (27%) reported treatment with fresh frozen plasma. Bleeding episodes were less common in patients using SFR versus non-SFR: three bleeds or fewer were reported by 92% SFR and 75% non-SFR patients. HFXD patients reported low well being in work/school/social activities with mean HFXD-adapted Hemophilia Well being Index. Patient symptoms negatively impacted caregiver burden with a mean HFXD-adapted Hemophilia Caregiver Index (±SD) of 15.9 (4.6), but also unexpectedly had a positive impact on self-worth and inner strength.To our knowledge, this is the first study to assess patient and caregiver burden of HFXD and impact on QoL. Improvements in symptom recognition, prompt diagnosis, and adherence to expert recommendations for treatment could improve QoL and decrease burden on HFXD patients and caregivers.

Acquired factor V and factor X Deficiency coexisting with acquired dysfibrinogenaemia in a patient with light chain myeloma.

An elderly woman with light chain myeloma presented with prolonged epistaxis and extensive cutaneous haematomas: her kappa/lambda ratio was high at 395, her coagulation screen, thrombin and reptilase times were abnormal, her FV and FX were in the low range in the absence of specific inhibitors, her Clauss fibrinogen was low at 0.95 g/l but antigenic FNG was 1.58 g/l. The patient denied treatment and died of progressive renal failure. We wish to describe the unusual association of FX and FV deficiency co-existing with an acquired dysfibrinogenaemia.

Plasma-derived human factor X concentrate for the treatment of patients with hereditary factor X deficiency.

INTRODUCTION: Hereditary factor X (FX) deficiency (HFXD) is an autosomal recessive rare bleeding disorder that leads to defects in the FX protein. Depending on the degree of deficiency, patients may be at risk of life-threatening bleeding episodes. Historical treatments for FX deficiency include prothrombin complex concentrates, which can increase the risk of thrombosis, and fresh frozen plasma, which can cause volume overload and transfusion reactions. Plasma-derived FX (pdFX), a single-factor, high-purity, high-potency human FX treatment, was approved in 2015 in the United States and in 2016 in Europe for on-demand treatment and prophylaxis of bleeding episodes and perioperative management of patients with HFXD. METHODS: Five studies that examined the use of pdFX in patients with mild (plasma FX activity [FX:C] ≥5 IU/dL), moderate (FX:C ≥1 and <5 IU/dL), or severe (FX:C < 1 IU/dL) HFXD were reviewed: TEN01, TEN02 and TEN03 were prospective, open-label, multicentre, nonrandomised studies, and TEN05 and TEN06 were multicentre retrospective studies. RESULTS: When used as an on-demand treatment, pdFX was judged by investigators to be successful in treating 41/42 (97.6%), 2/3 (66.6%) and 79/79 (100%) bleeds in TEN01, TEN02 and TEN05, respectively. When used prophylactically, pdFX was judged 'excellent' for the prevention of bleeds in nine (100%) and eight (100%) patients in TEN02 and TEN05, respectively. Perioperative treatment and pharmacokinetics were also assessed. pdFX was safe and well tolerated. CONCLUSIONS: Together, these studies support the use of pdFX for on-demand treatment of bleeding, routine prophylaxis, and perioperative management of bleeding in patients with HFXD.

Five new F10 variants in hereditary factor x deficiency detected by high-throughput sequencing.

INTRODUCTION: Factor X deficiency is a rare inherited bleeding disorder. To date, 181 variants are reported in the recently updated F10-gene variant database. AIM: This study aimed to describe new F10 variants. METHOD: The F10 gene was analysed in 16 consecutive families with FX deficiency by a targeted high-throughput sequencing approach, including F10, F9, F8 genes, and 78 genes dedicated to haematological malignancies. RESULTS: We identified 19 variants (17 missense, one nonsense and one frameshift) and two copy number variations. Two patients presenting a combined FVII-FX deficiency showed a loss of one F10 gene copy (del13q34) associated with a missense variant on the remaining allele, leading to a FX:C significantly lower than the FVII:C level and explaining their unusual bleeding history. We reported five novel variants. Three missense variants (p.Glu22Val affecting the signal peptide cleavage site, p.Cys342Tyr removing the disulphide bond between the FX heavy and light chains, and p.Val385Met located in FX peptidase S1 domain) were detected at compound heterozygosis status in three patients with severe bleeding symptoms and FX:C level below 10 IU/dL. Two truncating variants p.Tyr279* and p.Thr434Aspfs*13 leading to an altered FX protein were found at heterozygous state in two patients with mild bleeding history. CONCLUSION: This study showed the feasibility and the interest of high-throughput sequencing approach for rare bleeding disorders, enabling the report of F10 gene screening in a 3-weeks delay, suitable for clinical use. The description of five new variants may contribute to a better understanding of the phenotype-genotype correlation in FX deficiency.

Acquired factor X deficiency in a multiple myeloma without amyloidosis: a case report.

BACKGROUND: Multiple myeloma is one of the most common hematologic malignancies. Acquired factor X deficiencies are often observed in primary (AL) amyloidosis and rarely in multiple myeloma. OBJECTIVE: We report a case of an acquired factor X deficiency in a patient with a newly diagnosed IgA lambda multiple myeloma, without any evidence of concomitant amyloidosis. METHODS: We present the patient's medical history, clinical and physical examinations, laboratory analysis, and outcome. RESULTS: A 76-year-old male presented at the emergency department with ongoing gingival bleeding. Several analytical problems with blood sample analysis arose, which eventually led to the diagnosis of a multiple myeloma. Further exploration revealed an acquired factor X deficiency, explaining the ongoing bleeding. There was no evidence of concomitant amyloidosis. The multiple myeloma was treated, leading to complete remission of the malignancy and bleeding tendency. CONCLUSION: While coagulopathy is rarely observed in patients diagnosed with multiple myeloma, considering an acquired factor X deficiency becomes relevant when such patient present with bleeding diathesis.

Postmortem diagnosis of severe factor X deficiency in a fetus with intracranial hemorrhage resulting in intrauterine death.

In patients with severe congenital factor X deficiency, spontaneous intracranial hemorrhage (ICH) is particularly frequent in early childhood. We describe a case of fetal death at 26 weeks due to massive ICH. Gene panel analysis of postmortem samples revealed homozygosity for a pathologic F10 gene variant (c.1210T>C, p.Cys404Arg), which impedes correct folding of the catalytic serine protease domain and, therefore, causes a significant reduction in FX levels. The parents, not consanguineous but of the same ethnic community, were found to be heterozygous for this variant and did not have any personal or family history of abnormal bleeding. To the best of our knowledge, this is the first reported case of severe FX deficiency resulting in ICH diagnosed through postmortem genetic analysis. It illustrates the importance of exploring the etiology of fetal or neonatal ICH, which may impact future pregnancies, and the treatment of a potential coagulopathy in the child.

Preclinical development and characterization of a human plasma-derived high-purity factor X concentrate for therapeutic use.

INTRODUCTION: Hereditary factor X deficiency is a rare bleeding disorder, with limited treatment options. This paper describes the approach to pre-clinical development and characterization of a high-purity plasma-derived factor X concentrate, to achieve orphan drug marketing authorization for the treatment of hereditary factor X deficiency. METHODS: A chromatographic process was developed, to purify factor X from human plasma for fractionation. The product was characterized using in vitro, in vivo and ex vivo tests for potency, purity, thrombogenicity, immunogenicity, toxicity and stability. RESULTS: The production process complied with good pharmaceutical manufacturing practice. It achieved 6000-fold purification and 100-fold concentration of the factor X protein compared to human plasma. The factor X protein was 94%-96% pure. Other residual plasma proteins were well below levels in plasma, minimizing potential interference in hemostasis after therapeutic administration. Effective virus-reduction during manufacture, and the absence of thrombogenicity, toxicity and immunogenic potential were confirmed, addressing the main safety concerns historically associated with plasma-derived therapeutics. The freeze-dried product remained stable between +2°C and +30°C for at least three years. After reconstitution with water for injections, the factor X activity was maintained for at least 48 h at +18°C to +22°C. CONCLUSION: Targeted pre-clinical development of the first highly-purified concentrate to treat hereditary factor X deficiency is described. Following international guidelines for nonclinical safety testing, particular strategies were adopted for unmodified products derived from human blood plasma. This approach may also be relevant to the development of other ultra-orphan medicinal products.

Management of Acquired Factor X Deficiency Caused by In Vitro Non-neutralizing Anti-factor X Autoantibodies with Pre-emptive Corticosteroid Therapy.

Coagulation factor X (FX) deficiency causes severe hemorrhagic symptoms. We herein report a 90-year-old man with hemorrhagic symptoms and prolongation of prothrombin time (PT) and activated partial thromboplastin time (APTT). Cross-mixing tests showed a factor deficiency pattern, but administration of plasma products was not effective. Acquired coagulation factor deficiency was suspected, and immunosuppressive therapy was started. After the intervention, his hemorrhagic symptoms improved. A decrease in FX activity was later confirmed, and anti-FX autoantibody was retrospectively detected by an enzyme-linked immunosorbent assay. Immediate intervention is important for patients suspected of having acquired coagulation factor deficiency.

Role of individual factor X concentrate pharmacokinetic studies in perioperative management of AL amyloidosis-associated acquired factor X deficiency.

BACKGROUND: AL amyloidosis is associated with acquired factor X (FX) deficiency. Experience related to its management is limited to case reports and series using prothrombin complex concentrate, fresh frozen plasma, plasma exchange, recombinant activated factor seven, and desmopressin with limited and variable efficacy. FX concentrate has not been widely used in its management. STUDY DESIGN AND METHODS: We report our experience with the perioperative use of FX concentrate (Coagadex) in two patients with AL amyloidosis-associated acquired FX deficiency requiring surgery, using their individual pharmacokinetic studies to manage perioperative hemostasis. Pharmacokinetic studies involved obtaining post-infusion FX activity at 10 min, 2, and 4 h following the administration of FX concentrate to calculate the FX half-life. RESULTS: Both patients' plasma FX activity was successfully increased to provide perioperative hemostatic support. Monitoring FX activity post-surgery was also utilized to maintain FX activity levels to prevent post-operative bleeding. CONCLUSION: Pharmacokinetic studies have a useful role in tailoring preoperative FX repletion in patients with AL amyloidosis associated with acquired FX deficiency.

Identification of non-neutralizing anti-factor X autoantibodies in three Japanese cases of autoimmune acquired factor X deficiency.

INTRODUCTION: Autoimmune factor X (FX or F10) deficiency (AiF10D) is an extremely rare acquired haemorrhagic disorder characterized by a severe reduction in FX activity due to autoantibodies against FX. AIM: Anti-FX autoantibodies were investigated in four patients with suspected AiF10D, and their properties were analysed. METHODS AND RESULTS: Anti-FX auto antibodies in plasma were detected by ELISA with three of four cases. One case of anti-FX autoantibody negativity was later diagnosed as AL-amyloidosis. IgG1 and IgG3 coexisted in all anti-FX autoantibodies of the three patients with AiF10D (cases X1, X2, and X3). Western blot analysis showed that the antibodies were bound to the FX light chain for cases X2 and X3, but the binding was weak for case X1. When the fusion proteins of a secretory luciferase with full-length FX or its γ-carboxylated glutamic acid (Gla) domain were added to the plasma of the three patients, both fusion proteins were immunoprecipitated as antigen-antibody complexes. Contrarily, the latter fusion protein produced in the presence of warfarin demonstrated a decrease in the collection rate, suggesting that their autoantibodies recognized the light chain and regions containing Gla residues. Since all three patients were essentially negative for FX inhibitors, it was concluded that the anti-FX autoantibodies for these cases were predominantly non-neutralizing. The concentration of the FX antigen also significantly reduced in these patients, suggesting that anti-FX autoantibodies promote the clearance of FX. CONCLUSION: Immunological anti-FX autoantibody detection is highly recommended to ensure that AiF10D cases are not overlooked, and to start necessary immunosuppressive therapies.

Anesthesia strategy for factor X deficiency coagulopathy: case report

Abstract Factor X deficiency ranks among the rarest coagulopathies and has a variable presentation spectrum. We intend to present a proposal for anesthesia protocol for individuals with the coagulopathy. The excision of an ovarian neoplasm was proposed for a 26-year-old, female, ASA II patient, with congenital Factor X deficiency. Physical examination and lab tests were normal, except for Prothrombin Time (PT) 22.1s (VR: 8-14s), International Normalized Ratio (INR) 1.99 (VR: 0.8-1.2) and Activated Partial Thromboplastin Time (aPTT) 41.4s (VR: 25-37s). We concluded that a history of bleeding should always be investigated, along with a pre-anesthetic coagulation study.

[IgD multiple myeloma mimicking free light chain myeloma complicated by factor X deficiency: a case report]. / Myélome multiple à IgD mimant un myélome à chaines légères libres et compliqué de déficit en facteur X: à propos d'un cas.

IgD myeloma is an extremely rare haemopathy with severe clinical presentation. It can be confused with non-secretory or free light chain myeloma. We here report the case of a 72-year old female patient presenting with bone pain and diffuse ecchymosis and deterioration of her general condition. Laboratory tests showed monoclonal gammopathy associated with severe acute renal failure and low total protein (TP) (48%) with factor X deficiency. Etiological assessment confirmed the diagnosis of IgD lambda myeloma stage IIIb, according to Durie and Salmon, International Staging System (ISS) score III unfavorable cytogenetics. Patient's outcome was favorable after treatment with proteasome inhibitor, anti-CD 38 and corticosteroid therapy. Adequate treatment of IgD myeloma, using new therapeutic approaches and hematopoietic stem cell autotransplantation, can improve the prognosis.

Prevalence, clinical characteristics and treatment outcome of factor X deficiency in a consecutive cohort of primary light-chain amyloidosis.

Factor X (FX) deficiency is prevalent in light-chain (AL) amyloidosis but its clinical significance was not investigated deeply. We conducted a retrospective analysis of a consecutive cohort with 207 primary AL amyloidosis patients. FX deficiency was present in 129 patients (62.3%). Those with FX deficiency had higher dFLC (299.6 mg/L vs. 102.3 mg/L, P < 0.001), higher cardiac troponin I (0.05 µg/L vs. 0.02 µg/L, P < 0.001) and N-terminal pro-brain natriuretic peptide (3115 ng/L vs. 392 ng/L, P < 0.001), and more patients with bone marrow plasma cells > 10% (18.0% vs. 4.3%, P = 0.008). The prevalence of FX deficiency increased with the Mayo 2004 stage. FX-deficient patients exhibited inferior overall survival (P < 0.001) and progression-free survival (P < 0.001) than others. Fifty-five patients with FX deficiency received retesting of FX activity after anti-plasma cell therapy. The median variation in FX activity was + 6.8% (range, -24.5% ~ +73.4%). Better improvement of FX activity was observed in patients with complete hematologic response (+18.2% vs. +4.0%, P = 0.036) and at least one organ response (+14.4% vs. +3.4%, P = 0.024). FX deficiency is associated with a heavier disease burden and poorer survival in primary AL amyloidosis. Improvement of FX activity tends to appear in patients with better hematologic and organ responses after chemotherapy.

A review of the pharmacokinetics, efficacy and safety of high-purity factor X for the prophylactic treatment of hereditary factor X deficiency.

INTRODUCTION: Hereditary factor X (FX) deficiency (FXD) is a rare autosomal recessive bleeding disorder. Plasma-derived FX (pdFX) is a high-purity FX concentrate approved in the United States and Europe for the treatment and prophylaxis of bleeding episodes and for peri-operative management in patients with hereditary FXD (HFXD). AIM: To review pharmacokinetic dosing, efficacy, and safety data for pdFX as routine prophylaxis for HFXD. METHODS: Summary of the published pharmacokinetic and safety data from TEN01, TEN02, TEN05, and real-world publications of pdFX for prophylaxis. RESULTS: Pharmacokinetic modelling data from the phase 3 TEN01 study supported administration of pdFX 25 IU/kg twice weekly for routine prophylaxis in adolescents/adults (aged ≥12 years). Results from nine paediatric patients in the phase 3 TEN02 study and eight adolescents/adults (aged ≥12 years) in the retrospective data-collection TEN05 study, along with real-world evidence, showed that routine prophylaxis with pdFX ≈40 IU/kg twice weekly in patients aged <12 years and pdFX ≈25 IU/kg twice weekly in patients aged ≥12 years was effective in bleeding prevention. CONCLUSIONS: pdFX was well tolerated in clinical studies, with no new safety signals identified during routine prophylactic use. Based on current evidence, it is recommended that routine prophylaxis with pdFX be initiated at 25 IU/kg twice weekly in adults/adolescents ≥12 years of age, and at a dosage of 40 IU/kg twice weekly in children <12 years of age. Thereafter, FX levels should be closely monitored, and dosages should be adjusted according to clinical response and to maintain trough levels ≥5 IU/dl.