Abstract

BACKGROUND To account for interindividual variability in the pharmacokinetics (PK) of factor concentrates, PK-guided dosing is increasingly implemented in haemophilia patients. Calculations are based on provided label potency, but legislation allows a potency difference of ±20% between label and actual potency. It is unknown if these differences affect PK guidance. AIM: Explore the effects of potency differences on individual factor VIII (FVIII) PK parameters and the prediction of FVIII trough levels of dosing regimens. METHODS We analyzed individual preoperative PK profiling data from severe and moderate haemophilia A patients included in the OPTI-CLOT randomized controlled trial. Label and actual potency were compared, with data on potency provided by pharmaceutical companies. For both potencies, individual PK parameters were estimated and concentration-time curves were constructed by nonlinear mixed-effects modelling. Finally, we explored the effect of both the identified and the maximum legislated potency difference on predicted FVIII trough levels infused in a low and high dose regimen. RESULTS In 45/50 included patients, actual potency was higher than its label potency. The median potency difference was 6.0% (range -9.2% to 18.4%) and resulted in varying individual PK parameter estimates but practically identical FVIII concentration-time curves. As expected, predicted FVIII trough levels were linearly correlated to the actual dose. CONCLUSION It is not necessary to take potency differences into account when applying PK guidance of FVIII concentrates in haemophilia A patients. However, when the patient is switched to another FVIII batch after PK-guided dosing, trough levels may deviate ±20% from calculations based on label dose.

Abstract

Factor XIII (FXIII) deficiency is a rare but serious coagulopathy. FXIII is critical in blood coagulation, and FXIII deficiencies can lead to uncontrolled or spontaneous bleeding. FXIII deficiencies can be congenital or acquired; acquired FXIII deficiency can be categorized as autoimmune and non-autoimmune. Immunological tests to measure FXIII inhibitors are required to diagnose acquired FXIII deficiency; however, appropriate test facilities are limited, which increases the turnaround time of these tests. In the case of critical bleeding, delayed test results may worsen prognosis due to delayed treatment. Here, we report a case of acquired FXIII deficiency, followed by a review of FXIII deficiency cases in Japan. We performed a systematic review to investigate the present conditions of the diagnosis and treatment of FXIII deficiency, including the measurement of FXIII inhibitors in Japan. FXIII inhibitor testing was only performed in 29.7 of acquired FXIII deficiency cases. Clinical departments other than internal medicine and pediatrics were often involved in medical treatment at the time of onset. Therefore, it is important for doctors in clinical departments other than internal medicine and pediatrics to consider FXIII deficiency and perform FXIII inhibitor testing when examining patients with prolonged bleeding of unknown cause or persistent bleeding after trauma.

Abstract

INTRODUCTION Low dose factor VIII prophylactic therapy in hemophilia has not been well established till date. This randomized controlled trial compared the efficacy of twice vs. thrice weekly schedule of low dose prophylactic factor VIII in children with hemophilia A as evaluated by the bleeding rate and clinico-radiological evaluation. METHODS Thirty-three children with severe hemophilia A (≤18 years) were randomized into two groups. Baseline evaluation included detailed history, clinical (HJHS 2.1 score and FISH score) and radiological examination (Pettersson score and ultrasound score). Group 1 received twice weekly factor VIII prophylaxis while group 2 received thrice weekly factor VIII prophylaxis, the dose being 10 U/kg in both groups. All participants were followed up over next 6 months to one year. Data regarding acute bleeding episodes and repeat clinico-radiological assessment at the end of follow up were recorded. RESULTS We analyzed 14 children in twice weekly prophylaxis group and 16 children in thrice weekly prophylaxis group. Statistically insignificant difference was found between the bleeding rates in both the groups after prophylaxis with the median values of monthly bleeding rate being 0.17 and p-value of 0.79. The differences between the initial and final clinical and radiological scores within each group were found to be statistically significant. There was no significant difference in the clinical and radiological scores in between the groups. CONCLUSION Twice weekly FVIII therapy is effective, easily administered prophylactic schedule to prevent long-term complications of hemophilia A. Lay summaryHemophilia A is one of the most common congenital coagulation factor deficiencies. Low dose factor VIII prophylaxis is recommended for hemophilia in resource-poor settings to reduce the bleeding episodes and improve the quality of life, although the optimal schedule for the same has not been well established. A randomized controlled trial on 33 children with hemophilia A (≤18 years) was done to compare the efficacy of twice versus thrice weekly schedule of prophylactic factor VIII. Group 1 received twice weekly factor VIII prophylaxis while group 2 received thrice weekly factor VIII prophylaxis, the dose in both groups being 10 U/kg. They were evaluated by the bleeding rate and clinical (HJHS 2.1 score and FISH score) and radiological scores (Pettersson score and ultrasound score). All participants were followed up over next 6 months to one year. Data regarding acute bleeding episodes and repeat clinico-radiological assessment at end of follow up were recorded. When analyzed, statistically insignificant difference was found between the bleeding rates after the two prophylaxis regimes. There was a significant improvement between initial and final clinical and radiological scores in both the groups and no difference was recorded in between the groups. To conclude, twice weekly FVIII therapy is effective, easily administered prophylactic schedule to prevent long-term complications of hemophilia A.

Abstract

INTRODUCTION Obesity alters the pharmacokinetic (PK) properties of drugs making it difficult to determine the appropriate dose when administering weight-based medications. Alternative descriptors of body weight, such as lean body mass (LBM) and ideal body weight (IBW), are sometimes used in these situations. METHODS We performed a single-centre, randomized, controlled, open-label, 3 × 3 crossover trial to determine whether recombinant factor VIII (rFVIII) dosing based on LBM and IBW achieves a targeted FVIII recovery with better precision than based on total body weight (TBW) in overweight and obese, adult males with haemophilia A. Participants were randomized to 1 of 6 possible FVIII concentrate dosing sequence scenarios (TBW, LBM and IBW). Recombinant FVIII was administered on 3 separate weeks following a washout period of at least 72 hours. RESULTS A total of 19 participants were randomized and completed the study. FVIII recovery was lower at 30 minutes post-rFVIII infusion in LBM vs TBW and IBW vs TBW-based dosing, mean difference -0.38 (95% CI: -0.56, -0.20) and -0.28 (95% CI: -0.47, -0.10) IU/dL per IU/kg, respectively. In LBM vs TBW and IBW vs TBW-based dosing, there was a non-significant increase in the proportion of participants with a targeted FVIII recovery of 2.00 ± 0.20 IU/dl per IU/kg, OR = 1.93 (95% CI: 0.44, 8.55) and OR = 3.65 (0.80, 16.72), respectively. DISCUSSION Based on our study's findings, overweight and obese patients with haemophilia A may benefit from an individualized PK analysis using LBM and IBW to determine the most accurate, and potentially cost-effective, method of achieving targeted FVIII recovery.

Abstract

STUDY OBJECTIVE This study compares the safety and efficacy of a fixed dose of 4-factor prothrombin complex concentrate (4FPCC) to the FDA-approved variable dosing for reversal of warfarin-induced anticoagulation. METHODS This was a single-center, prospective, open-label, randomized controlled trial with subjects randomized to 4FPCC at a fixed dose of 1500 IU or the FDA-approved variable dosing regimen. The primary efficacy outcome (reversal success) was defined as a post-intervention international normalized ratio (INR) of less than or equal to 1.5. Given that 4FPCC is the standard of care for reversal of warfarin-induced anticoagulation an active-controlled approach was employed with the two dosing regimens compared based on efficacy, cost, and safety outcomes. RESULTS 71 subjects (34 in the fixed dose group and 37 in the variable dose group) completed the study. There were no significant differences in age, gender, weight, initial INR, or indication for 4FPCC administration between the two treatment groups. Reversal success in the fixed-dose group was 61.8%, while in the variable dose group reversal success was 89.2%. Reversal success in the fixed-dose group was significantly lower than the rate of reversal success in the variable dose group (27.4% lower, p = 0.011). CONCLUSION The results of this study provide evidence that fixed dosing results in lower reversal success rates as compared to variable dosing of 4FPCC for warfarin-induced anticoagulation.

Abstract

The development of thrombocytopenia and thrombosis after the administration of the AstraZeneca and Johnson & Johnson/Janssen vaccines has been recently described. This new condition has been called vaccine-induced immune thrombotic thrombocytopenia. The objective of this review is to summarize the clinical characteristics and therapeutic options of vaccine-induced immune thrombotic thrombocytopenia based on available published case series. Furthermore, we provide a comparison of the diagnostic pathway and treatment recommendations provided by six major medical societies. DATA SOURCES We searched MEDLINE, PubMed, and Cochrane Central Register of Controlled Trials databases. STUDY SELECTION We included case series and case reports on patients who developed vaccine-induced immune thrombotic thrombocytopenia. We also included guidelines for the diagnosis and management of vaccine-induced immune thrombotic thrombocytopenia from major medical societies. DATA EXTRACTION We examined baseline risk factors, symptoms, physical signs, laboratory and imaging findings, and treatment in patients with vaccine-induced immune thrombotic thrombocytopenia reported in the case series. We also analyzed the diagnostic and treatment recommendations provided by major societal guidelines on the management of vaccine-induced immune thrombotic thrombocytopenia. DATA SYNTHESIS Patients who developed vaccine-induced immune thrombotic thrombocytopenia were more likely to be young women (age 20-50) who were given the AstraZeneca or Johnson & Johnson/Janssen 4-28 days prior to presentation. Patients showed signs, symptoms, and imaging findings consistent with cerebral venous sinus thrombosis and splanchnic thrombosis. Laboratory findings showed thrombocytopenia, low fibrinogen, and elevate d-dimer levels, while positive platelet factor 4 antibodies were always positive. Major societal guidelines recommend avoidance of heparin and platelets. Treatment with nonheparin anticoagulants and IV immunoglobulin is also recommended. CONCLUSIONS Vaccine-induced immune thrombotic thrombocytopenia is a rare but highly morbid complication related to the administration of the AstraZeneca and Johnson & Johnson/Janssen vaccines. Clinicians should be prepared for the early identification of patients with suspicious symptoms and prompt treatment should be initiated to avoid catastrophic deterioration. Major societal guidelines provide useful recommendations for the diagnosis and management of patients with vaccine-induced immune thrombotic thrombocytopenia.

Abstract

There are potential concerns related to bleeding caused by oral anticoagulants, especially in the elderly. Andexanet alfa has been authorized for use to reverse the effects of oral anticoagulants. Off-label use of four factor prothrombin complex concentrate (4F-PCC) for the reversal of oral factor Xa inhibitors is common. However, not much is known about their efficacy and safety profile. The intent of this meta-analysis was to evaluate the efficacy and safety of 4F-PCC and andexanet alfa for management of major bleeding due to oral factor Xa inhibitors. Comprehensive searches were done systematically through PubMed, Scopus and Google scholar databases. Studies that were retrospective record based or adopted prospective cohort approach and reported either of the three main outcomes, i.e., achieved hemostasis rate or rate of thrombotic events or mortality rate were included in the meta-analysis. Statistical analyses were done using STATA version 13.0. A total of 22 studies were included in the meta-analysis. All the studies had a single arm with no control/comparator group. The pooled rate of good to excellent hemostatic control upon use of andexanet was 80% (95% CI; 72% to 88%) and for 4F-PCC, it was 76% (95% CI; 70% to 83%). A comparatively higher pooled rate of thrombotic complications upon use of andexanet [13% (95% CI; 5% to 20%) was noted, compared to use of aPCC/4F-PCC [4% (95% CI; 3% to 5%). The pooled all-cause mortality rate within 30 days of administration was 24% (95% CI; 12% to 35%) with andexanet use and 19% (95% CI; 14% to 25%) for aPCC/4F-PCC. The findings suggest that use of both andexanet and aPCC/4F-PCC achieves a good hemostasis but there is an associated risk of thrombotic events and mortality. Future studies should have a control group to better establish evidence on efficacy and safety of these agents.

Abstract

BACKGROUND In childhood immune thrombocytopenia (ITP), an autoimmune bleeding disorder, there is a need for better prediction of individual disease courses and treatment outcomes. OBJECTIVE To predict the response to intravenous Immunoglobulins (IVIg) and ITP disease course using genetic and immune markers. METHODS Children aged below seven years with newly diagnosed ITP (N = 147) from the TIKI study were included, which randomized children to an IVIg or observation group. A total of 46 variables were available: clinical characteristics, targeted genotyping, lymphocyte immune phenotyping, and platelet autoantibodies. RESULTS In the treatment arm, 48/80 children (60%) showed a complete response (platelets ≥100 x 10(9) /L) that lasted for at least one month (complete sustained response; CSR) and 32 exhibited no or a temporary response (absence of a sustained response; ASR). For a biological risk score, five variables were selected by regularized logistic regression that predicted ASR vs CSR: 1) hemoglobin; 2) platelet count; 3) genetic polymorphisms of FcγRIIc; 4) the presence of IgG anti-platelet antibodies; and 5) preceding vaccination. The ASR sensitivity was 0.91 (95% CI, 0.80 - 1.00) and specificity was 0.67 (95% CI, 0.53 - 0.80). In the 67 patients of the observation arm, this biological score was also associated with recovery during one-year follow-up. The addition of the biological score to a predefined clinical score further improved the discrimination of favorable ITP disease courses. CONCLUSIONS The prediction of disease courses and IVIg treatment responses in ITP is improved by using both clinical and biological stratification.

Abstract

INTRODUCTION Given the relatively small number of patients with haemophilia A, head-to-head comparisons between recombinant FVIII (rFVIII) products are difficult to conduct. This study compared the efficacy and consumption of rVIII-SingleChain (lonoctocog alfa, AFSTYLA(®)) with rAHF-PFM (octocog alfa, Advate(®)) and rFVIIIFc (efmoroctocog alfa, Elocta(®)), for the prophylaxis and treatment of bleeding episodes in previously treated adolescents/adults with severe haemophilia A, through a matching-adjusted indirect comparison (MAIC). METHODS A systematic literature review identified published clinical trials for rAHF-PFM and rFVIIIFc. Individual patient data for rVIII-SingleChain were used to match baseline patient characteristics to those from published trials, using an approach similar to propensity score weighting. After matching, annualized bleeding rates (ABR), percentage of patients with zero bleeds, and rFVIII consumption were compared across trial populations. RESULTS Published data were identified from two rAHF-PFM trials and one rFVIIIFc trial. rVIII-SingleChain had similar ABR (risk ratio [RR]: 0.74 [0.16; 3.48]; RR: 1.18 [0.85; 1.65]) and percentage of patients with zero bleeds (odds ratio [OR]: 1.34 [0.56; 3.22]; OR: 0.78 [0.47; 1.31]) versus rAHF-PFM and rFVIIIFc, respectively. Annual rVIII-SingleChain consumption was significantly lower than rAHF-PFM (mean difference: - 1507.66 IU/kg/year [- 2011.71; - 1003.61]) and equivalent to rFVIIIFc (RR: 0.96 [0.62; 1.49]). CONCLUSION Although limited to published information for comparator trials, these results suggest that with an annualized rFVIII consumption comparable to rFVIIIFc, but significantly lower than rAHF-PFM, routine prophylaxis with rVIII-SingleChain is able to maintain a similar ABR and percentage of patients with zero bleeds, attesting to the long-acting nature of rVIII-SingleChain.

Abstract

INTRODUCTION In underdeveloped countries, patients with hemophilia often experience repetitive ankle joint hemorrhages due to a shortage of coagulation factors (factor VIII [FVIII] and factor IX [FIX] for hemophilia A and B, respectively). AREAS COVERED This is a narrative literature review in which we searched the Cochrane Library and MEDLINE for articles related to ankle arthrodesis in patients with hemophilia. The searches covered the period from the databases´ inception to February 28, 2021. In the event of unsuccessful hematologic prophylaxis and conservative measures (e.g., analgesics, cyclooxygenase-2 inhibitors, taping, intra-articular injections of hyaluronic acid and corticosteroids, physical and rehabilitation medicine, orthoses, radiosynovectomy, and joint-preserving surgery (e.g., removal of the distal tibia by open surgery or by arthroscopic surgery, joint debridement by arthroscopic surgery), the only surgical solution is ankle arthrodesis, which does not preserve the ankle joint. EXPERT OPINION Ankle pain is reduced after ankle arthrodesis (75% of patients experience no pain). Approximately 5% of patients require reoperation due to lack of fusion, and deep infection occurs in 2.5%. After tibiotalar fusion, a self-reported activity scale shows that approximately 12% of patients improve, 9% worsen, and 79% show no improvement. The results of ankle arthrodesis therefore appear to be poor.