Discrepancy between the results of one-stage and chromogenic factor VIII: C assays in patients with mild/moderate hemophilia A.

: Diagnosis of hemophilia A is generally based on the measurement of plasma factor VIII activity (FVIII:C) using the one-stage assay (OSA) or the two-stage chromogenic substrate assay (CSA). The results of these methods show considerable discrepancy in about one-third of non-severe hemophilia A patients. The aim of this study was to assess the prevalence of FVIII:C assay discrepancy in non-severe hemophilia A patients in Iran and the relationship between the bleeding tendency with the level of FVIII:C by each method. Patients registered as mild or moderate hemophilia A in hemophilia clinic of Imam Khomeini Hospital were included. In each patient, FVIII:C level was assessed using one-stage (FVIII:C1) and chromogenic (FVIII:CR) methods. Assay discrepancy was defined as a two-fold or greater difference between the results of two assays. Bleeding tendency of the patients was recorded based on 'ISTH-BAT'. Sixty male patients were eligible for the study. The levels of FVIII:C1 was higher than FVIII:CR in 90% of patients. Assay discrepancy was seen in 41 (68%) patients. The classification of hemophilia A in 23 (38%) patients was modified by chromogenic method. No significant correlation was noted between the results of ISTH BAT with FVIII:C levels of each method. Regarding the prevalence of FVIII:C assay discrepancy in 2/3 of our non-severe hemophilia A patients, high rate of disease severity modification by chromogenic method and no significant relation between the clinical bleeding phenotype with any method, the authors highly recommend to perform both FVIII:C assays for the diagnosis and classification of non-severe hemophilia A.

Inhibitor development in patients with congenital factor VII deficiency, a study on 50 Iranian patients.

: Congenital factor VII (FVII) deficiency is a rare bleeding disorder with an estimated prevalence of 1 per 500 000 in the general population. On-demand replacement therapy is the main therapeutic choice in patients with congenital FVII deficiency. Inhibitor formation against exogenous FVII is very rare and can cause challenges in the management of the disorder. The present study was conducted to assess the prevalence of FVII inhibitor in 50 patients with congenital FVII deficiency under on-demand or prophylaxis treatment by recombinant activated FVII. All patients with confirmed congenital FVII deficiency were assessed for inhibitor development in regular intervals. Inhibitor titer was determined by a modified Nijmegen-Bethesda assay. The study results were analyzed by SPSS software. Among all cases, two patients (4%) developed an FVII inhibitor. Case 1 was a 14-year-old boy with severe FVII deficiency (FVII activity <1%) with regular prophylaxis. The patient was a high-responder with high-titer FVII inhibitor (170 Bethesda Unit). This patient, who had a history of intracranial hemorrhage, had undergone brain surgery three times. The second patient was a 70-years old man with on-demand therapy that also developed a high-titer inhibitor (10 Bethesda Unit). This patient had experienced easy bruising and endured a few surgeries for his brain tumor and, finally, succumbed to the disease. Although the inhibitor formation is a rare phenomenon, it may result in a significant challenge to manage the affected patients.

Cost-Effectiveness Analysis of Biogeneric Recombinant Activated Factor VII (AryoSeven™) and Activated Prothrombin Complex Concentrates (FEIBA™) to Treat Hemophilia A Patients with Inhibitors in Iran.

Nowadays, bypassing agents such as recombinant activated factor VII (rFVIIa) and activated prothrombin complex concentrates (aPCC) are used to treat bleeding episodes in the Hemophilia patients with inhibitors. AryoSeven® is an Iranian biogeneric rFVIIa with homogeneity of efficacy and the nature to NovoSeven in a comparative trial. The current clinical trial aimed to evaluate the cost-effectiveness of FEIBA and AryoSeven® by Decision Analytic Model according to the Iranian healthcare system. An open label, multi-center, cross-over clinical trial was designed. Patients were categorized into 3 groups based on their prior tendency to one or none of the products. To determine the premium therapeutic strategy, the Incremental cost-effectiveness ratio (ICER) was calculated. Protocol F led to more treatment success in group F than the other groups (P= 0.03). Also, there was a significant statistical difference between the mean of effectiveness scores in the groups using protocol F (P = 0.01). The effectiveness of protocol F and A were 89% and 72%, respectively. ICER cost US$ to manage an episode of bleeding to get one more unit of effectiveness using FEIBA VS. AryoSeven. Although the results showed that AryoSeven was more cost-effective compared to FEIBA, the two strategies were undominated. In other words, both medicines can be applied in the first line of the treatment if the cost of FEIBA was reduced. The present clinical trial was registered at IRCT website, under ID No.2013020612380N1.

Comparative measurement of anti-factor VIII antibody by Bethesda assay and ELISA reveals restricted isotype profile and epitope specificity.

Factor VIII (FVIII) inhibitor antibodies are produced against functional epitopes of FVIII in about 30% of severe hemophilia A patients leading to inhibition of its procoagulant activity. The Bethesda assay, the most commonly used method to measure FVIII inhibitors, based on inhibition of coagulant activity of FVIII, is neither able to detect noninhibitory antibodies nor their isotype. In this study we employed an indirect enzyme-linked immunosorbent assay (ELISA) to measure dif ferent isotypes and IgG subclasses of anti-FVIII anti body in the plasma of hemophiliacs (with and without inhibitor) and normal individuals using recombinant FVIII-coated microtiter plates. The results showed a predominance of IgG and IgG4, though IgA was slightly elevated in a few inhibitor-positive patients and IgM was hardly detectable. A highly significant correlation was found between the Bethesda titer and the optical density values of total Ig, IgG and IgG4 anti-FVIII antibodies obtained by ELISA (p<0.0001). These findings suggest a restricted specificity of anti-FVIII response in hemophiliacs towards functional epitopes of the molecule. Furthermore, high specificity and reasonable sensitivity of the ELISA, together with other technical advantages, suggest this method as a suitable supplementary technique for rapid large-scale screening of inhibitor-positive samples, though ELISA-negative samples need to be rechecked by the Bethesda assay to identify patients with a low inhibitor titer.