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- Ljung, Rolf
(författare)
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Aspects of haemophilia prophylaxis in Sweden.
- 2002
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Ingår i: Haemophilia. - : Wiley. - 1351-8216 .- 1365-2516. ; 8:Suppl 2, s. 34-37
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Tidskriftsartikel (refereegranskat)abstract
- Prophylactic treatment of haemophilia has been gaining acceptance as the optimal therapeutic option in an increasing number of haemophilia centres in the developed world in recent years. This paper focus on three aspects of prophylactic therapy: when to start treatment, venous access and the dose/dose interval. Evidence is in favour of prophylactic treatment to be started at an early age using either a peripheral vein with 1-2 injections per week and a successive increase in the frequency depending on the child and the veins, or, using a Port-A-Cath which allows a better prophylactic coverage by infusions preferably every second day in haemophilia A and every third day in haemophilia B.
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| 2. |
- Abshire, T. C., et al.
(författare)
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Prophylaxis in severe forms of von Willebrand's disease: results from the von Willebrand Disease Prophylaxis Network (VWD PN)
- 2013
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Ingår i: Haemophilia. - : Wiley. - 1351-8216. ; 19:1, s. 76-81
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Tidskriftsartikel (refereegranskat)abstract
- The bleeding patterns of severe von Willebrand's disease (VWD) adversely affect quality of life, and may be life threatening. There is a presumed role for prophylaxis with VWF-containing concentrates, but data are scarce. The von Willebrand Disease Prophylaxis Network (VWD PN) was formed to investigate the role of prophylaxis in clinically severe VWD that is not responsive to other treatment(s). Using a retrospective design, the effect of prophylaxis was studied. Availability of records to document, or reliably assess, the type and frequency of bleeding episodes prior to, and after, the initiation of prophylaxis was required. Annualized bleeding rates were calculated for the period prior to prophylaxis, during prophylaxis and by primary bleeding indication defined as the site accounting for more than half of all bleeding symptoms. The Wilcoxon signed-rank test of differences in the medians was used. Sixty-one subjects from 20 centres in 10 countries were enrolled. Data for 59 were used in the analysis. The median age at onset of prophylaxis was 22.4 years. Type 3 VWD accounted for the largest number (N = 34, 57.6%). Differences in bleeding rates within individuals during compared with before prophylaxis were significant for the total group (P < 0.0001), and for those with primary bleeding indications of epistaxis (P = 0.0005), joint bleeding (P = 0.002) and GI bleeding (P = 0.001). The effect of prophylaxis was similar among those age < 18 years and those >= 18. One person developed an inhibitor during treatment. We conclude that prophylactic treatment of VWD is efficacious.
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| 5. |
- Ahnström, Josefin, et al.
(författare)
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A 6-year follow-up of dosing, coagulation factor levels and bleedings in relation to joint status in the prophylactic treatment of haemophilia
- 2004
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Ingår i: Haemophilia. - : Wiley. - 1351-8216 .- 1365-2516. ; 10:6, s. 689-697
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Tidskriftsartikel (refereegranskat)abstract
- The primary aim of this study was to investigate the possible relationship between coagulation factor level and bleeding frequency during prophylactic treatment of haemophilia after stratification of the patients according to joint scores. The secondary aim was to obtain a systematic overview of the doses of coagulation factors prescribed for prophylaxis at the Malmo haemophilia treatment centre during a 6-year period. A retrospective survey of medical records for the years 1997-2002 and pharmacokinetic study results from the 1990s was complemented by collection of blood samples for coagulation factor assay when needed. Information on the dosing and plasma levels of factor VIII or factor IX, joint scores and incidence of bleedings (joint bleeds and 'other bleeds') was compiled. The patients were stratified by age (0-6, 7-12, 13-18, 19-36 and >36 years) and joint score (0, 1-6 and >6). Individual pharmacokinetic parameters of plasma coagulation factor activities (FVIII:C and FIX:C) were estimated. Trough levels during the treatment were calculated, as well as the number of hours per week of treatment during which plasma FVIII:C/FIX:C fell below a 1, 2 or 3% target level. Fifty-one patients with haemophilia A (two moderate, 49 severe) and 13 with haemophilia B (all severe) were included, yielding data for 364 patient-years of treatment. There was a wide range of dosing schedules, the most common ones being three times a week or every other day for FVIII and twice a week or every third day for FIX. The overall relationship between FVIII:C/FIX:C levels and incidence of joint bleeding was very weak, even after stratification of the patients according to joint score. There was no relationship between coagulation factor level and incidence of other bleeds. In this cohort of patients on high-dose prophylactic treatment, dosing was based more on clinical outcome in terms of bleeding frequency than on the aim to maintain a 1% target level of FVIII:C/FIX:C. Some patients did not bleed in spite of a trough level of <1% and others did in spite of trough levels >3%. The practical implication of our findings is that dosing in prophylactic treatment of haemophilia should be individualized. Thus, proposed standard regimens should be implemented only after careful clinical consideration, with a high readiness for re-assessment and individual dose tailoring.
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| 8. |
- Andersson, Nadine, et al.
(författare)
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Genetic screening of children with suspected inherited bleeding disorders
- 2020
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Ingår i: Haemophilia. - : Wiley. - 1351-8216 .- 1365-2516. ; 26:2, s. 314-324
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Genetic screening using high-throughput DNA sequencing has become a tool in diagnosing patients with suspected inherited bleeding disorders (IBD). However, its usefulness and diagnostic efficacy in children is unclear.AIM: To evaluate the diagnostic efficacy of genetic screening for IBD in children and downstream further testing.METHODS: After informed consent, children (<18 years) with suspected IBD underwent genetic screening with 94 selected genes.RESULTS: A total of 68 heterozygous class 3-5 variants were detected in 30 children, 2.3 variants per patient. Directed specific functional testing was performed after genetic screening in a subset of patients. Adhering to the ACMG guidelines, the results of functional testing together with family history and previous publications classified three variants as likely disease causing (class 4) and two variants as disease causing (class 5), all in children with thrombocytopenia. The overall diagnostic rate was 16.7% (5/30). Children with thrombocytopenia had a significantly higher rate of significant genetic findings, 5/9 (55.6%) vs. 0/21 (0%; P = .0009).CONCLUSION: We conclude that performing genetic screening in children is an effective tool especially for children with inherited thrombocytopenia and has the possibility to diagnose platelet disorders adequately early in life. Children with bleeding diathesis, normal coagulation work-up and without thrombocytopenia are unlikely to be diagnosed by genetic screening. Ethical issues such as incidental findings, variants associated with cancer and the interpretation of the genetic results into clinical practice remain problematic.
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| 17. |
- Arvanitakis, Alexandros, et al.
(författare)
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A comparison of MyPKFiT and WAPPS-Hemo as dosing tools for optimizing prophylaxis in patients with severe haemophilia A treated with Octocog alfa
- 2021
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Ingår i: Haemophilia. - : Wiley. - 1351-8216 .- 1365-2516. ; 27:3, s. 417-424
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: MyPKFiT and the Web-Accessible Population Pharmacokinetic service—Hemophilia (WAPPS-Hemo) are web-based population-based applications developed for helping physicians individualize and optimize replacement therapy. Although MyPKFiT is intended for Octocog alfa and Rurioctocog alfa pegol use only, the WAPPS-Hemo is applicable to all factor VIII concentrates. Aim: To compare MyPKFiT and WAPPS-Hemo as dosing tools for optimizing treatment of patients with severe haemophilia A on regular prophylaxis with Octocog alfa in a real-world setting. Methods: Fourteen patients with severe haemophilia A (median age 30.8 years; range 20–71) were enrolled. The FVIII activity was measured twice after a regular dose of Octocog alfa by the chromogenic and the one-stage assays. PK analyses were performed using each tool and dosing estimations to reach trough levels of 1%, 3% or 5% after 48 h. Findings were calculated and compared. Results: The two PK algorithms yielded similar t½ independent of the type of FVIII assay used. However, there were significant differences in the time to reach 1%, 3% and 5%. The WAPPS-Hemo generated 10–12 h longer time to a trough of 1% and up to 4 h for the troughs of 3% and 5%. Accordingly, the doses estimated by WAPPS-Hemo for a daily regimen were between 28% and 100% of those proposed by MyPKFiT. Conclusions: MyPKFiT and WAPPS-Hemo provided similar half-life estimations for Octocog alfa independent of the FVIII assay used. The doses suggested by WAPPS-Hemo to reach specific troughs were overall lower, which may have implications for treatment optimization.
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| 18. |
- Arvanitakis, Alexandros, et al.
(författare)
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Clinical outcome and adherence rate in Scandinavian patients with intermediate-intensity prophylaxis before and after the switch of standard half-life FVIII products to BAY 81–8973
- 2022
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Ingår i: Haemophilia. - : Wiley. - 1351-8216 .- 1365-2516. ; 28:2, s. 223-229
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Treatment optimization in haemophilia A can be achieved by choice of FVIII product and knowledge of pharmacokinetics (PK), phenotype and adherence. A favourable PK profile of BAY 81–8973 (octocog alfa) (Kovaltry, Bayer AB) compared to other standard half-life (SHL) FVIII products has been suggested. Aim: To evaluate whether the switch to BAY 81–8973, using the same dosing schedule, impact factor consumption and bleed rates, taking arthropathy and adherence into account. Methods: Forty patients on prophylaxis with SHL (median age 40.5 years) attending the haemophilia treatment centres in Malmö and Oslo were enrolled. The annualised bleeding rate (ABR) and joint bleeding rate (AJBR) before and after the switch to BAY 81–8973 was calculated. PK analyses were performed with WAPPS-Hemo. Joint health status and treatment adherence were assessed. Results: The median ABR and AJBR was 0 before and after the switch, at both centres. The median yearly factor consumption was 3,345 IU/Kg/year in the entire study group corresponding to intermediate-intensity prophylaxis in most patients and with significantly more used in Malmö (3,862 IU/Kg/year), compared to Oslo (2,337 IU/Kg/year) (P.006). There was no correlation between arthropathy and bleeding. The median BAY 81–8973 t½ was 20 h (range 7.5–29 h), with significant correlation to VWF levels, and 13.4 h after exclusion of VWF outliers. Adherence to treatment was 97%. Conclusions: Concentrate switch, using mainly intermediate-intensity regimens with high adherence rates, preserves excellent prophylaxis outcome using standard half-life FVIII products, indicating the value of individualized prophylaxis and close follow-up.
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| 19. |
- Arvanitakis, Alexandros, et al.
(författare)
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Impact of timing of prophylaxis commencement, F8 genotype and age on factor consumption and health-related quality of life in patients with severe haemophilia A
- 2023
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Ingår i: Haemophilia. - 1351-8216. ; 29:4, s. 1032-1038
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The timing of prophylaxis and F8 genotype can impact treatment outcomes in adults with severe haemophilia A (HA). Aim: To investigate how F8 genotype, timing, and type of prophylaxis influence arthropathy, bleeding rates, factor consumption and health-related quality of life (HRQoL). Methods: Thirty-eight patients with severe HA were enrolled. Bleeding events were recorded retrospectively during median 12.5 months. F8 gene variants were classified as null or non-null. Joint health and HRQoL were assessed with HJHS and EQ-5D-5L, respectively. Results: The median age at prophylaxis start was 1.25 years in the primary prophylaxis group (N = 15, median age 26 years) and 31.5 years in the secondary group (N = 22, 45 years), respectively. There were significant differences in the medians of HJHS (4 vs. 20, p <.001), EQ-5D-5L index (0.9647 vs. 0.904, p =.022), EQ VAS (87 vs. 75, p =.01) and FVIII consumption (3883 vs. 2737 IU/kg/year, p =.02), between the primary and secondary groups, respectively. Median annualized bleeding rate (ABR) was 0 for both groups. Twenty-five null and thirteen non-null F8 gene variants were identified. In the secondary prophylaxis group, lower median FVIII consumption (1926 vs. 3370 IU/kg/year) was shown for non-null compared to null variants, respectively, with similar ABR and HJHS. Conclusion: Delayed prophylaxis start with intermediate dose intensity prevents bleeds but at a cost of more arthropathy and reduced HRQoL, compared to higher intensity primary prophylaxis. Non-null F8 genotype may allow lower factor consumption with similar HJHS and bleeding rates, compared to null genotype.
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| 20. |
- Arvanitakis, Alexandros, et al.
(författare)
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Primary prophylaxis implementation and long-term joint outcomes in Swedish haemophilia A patients
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Ingår i: Haemophilia. - 1351-8216.
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Primary prophylaxis is the gold standard in severe haemophilia A (SHA) but time to escalate the prophylaxis regimen varies. Aim: Assess prophylaxis implementation and long-term joint health outcomes in SHA with primary prophylaxis. Methods: Adult male patients born after 1980, with SHA on primary prophylaxis, started before the age of 3 years and second joint bleed, and no history of FVIII inhibitors, were enrolled. Repeated joint-health examinations were performed with HJHS or HEAD-US; VERITAS-PRO assessed adherence. Results: Thirty patients were enrolled with, at inclusion, median age 33.5 years, annualized bleed rate and joint bleed rate 0, and FVIII consumption 4232 IU/kg/year, respectively. The median age was 1.2 years, at prophylaxis start once weekly with a median FVIII dose of 47.7 IU/kg, and 1.7 years, by the time escalation to a final regimen had occurred, with a median infusion frequency of thrice weekly and FVIII dose 41.7 IU/kg, respectively. Older age correlated with later transition to escalated prophylaxis (p <.001). Longer time to escalated prophylaxis correlated to more bleeds (p <.001). Median HJHS increased slowly, reaching 4 at 35–40 years. HJHS at 15–20 years correlated with higher HJHS afterwards. Median total HEAD-US score was 1 and correlated with HJHS (p <.001). Median VERITAS-PRO score was 36, indicating good treatment adherence. Conclusion: Primary prophylaxis is effective but does not completely prevent the gradual development of arthropathy in SHA. Joint assessments with HJHS should start at an early age, as they correlate with arthropathy in later life. Prophylaxis escalation should proceed expeditiously to prevent bleeds.
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| 22. |
- Astermark, Jan
(författare)
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Basic aspects of inhibitors to factors VIII and IX and the influence of non-genetic risk factors.
- 2006
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Ingår i: Haemophilia. - 1351-8216. ; 12 Suppl 6, s. 41499-41499
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Tidskriftsartikel (refereegranskat)abstract
- The appearance of polyclonal antibodies inhibiting the function of exogenous factors VIII (FVIII) and IX (FIX) continues to be a major challenge in the treatment of patients with congenital haemophilia. Why these inhibitors develop in 10-20% of patients with haemophilia A, and in 1-5% of patients with haemophilia B, remains largely unexplained. The antibodies, however, are characterized by several features that may have implications for the immune process by which they occur. The FVIII antibodies are mainly directed towards the A2, A3 and C2 domains, thereby interfering with the function of the factor Xase complex, the binding of FVIII to von Willebrand factor, and the binding of FVIII to phospholipid membranes. The FIX epitopes are localized to the NH2-terminal gamma-carboxyglutamic acid region and the serine protease domain. Genetic risk factors are known to be of importance in the development of inhibitors, whereas the impact of non-genetic factors is less clear. However, based on studies of related subjects, it is obvious that non-genetic factors are of importance as well. Putative factors currently debated include age at the start of treatment, treatment in association with immune challenges, the type of product, and the mode of administration. Most of the findings reported to date, however, derive from small cohorts that have not been sufficiently well characterized with respect to genetic risk profile. Therefore, additional studies are required to quantify the impact of non-genetic factors on the pathophysiologic process of inhibitor development.
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| 23. |
- Astermark, Jan, et al.
(författare)
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Clinical issues in inhibitors
- 2010
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Ingår i: Haemophilia. - : Wiley. - 1351-8216 .- 1365-2516. ; 16, s. 54-60
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Forskningsöversikt (refereegranskat)abstract
- Anamestic inhibitors represent the major complication of haemophilia therapy now that clotting factor concentrates are virtually free of pathogen-transmission risk. Conventional clotting factor replacement is usually insufficient to prevent or treat bleeding in a haemophilia patient with a high responding inhibitor so that alternative treatment with bypassing agents is required. Despite their relative efficacy, their use does not achieve the same invariable haemostasis that patients without inhibitors do following treatment with factor concentrate replacement. This has led to the attempt to eradicate such inhibitors with immune tolerance induction. Success is not invariable, however, and many patients with long-term persistent high-titre inhibitors continue to experience great morbidity. Recently, this has given rise on a limited basis to attempts to use bypassing agents in prophylaxis regimens in an effort to alleviate this extreme morbidity. Each of these strategies is discussed in the context of their relative benefits and risks.
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| 24. |
- Astermark, Jan, et al.
(författare)
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Comparison of single subject and population-based pharmacokinetics for optimizing prophylaxis with simoctocog alfa in patients with haemophilia A
- 2021
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Ingår i: Haemophilia. - : Wiley. - 1351-8216 .- 1365-2516. ; 27:4, s. 626-633
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The use of pharmacokinetic assessment for optimal prophylactic dosing of factor concentrates in haemophilia has gained increasing enthusiasm over the last decade. However, blood sampling on several occasions is burdensome and limited sampling using population-based PK is appealing. Aim: To compare the pharmacokinetics and dosing recommendations for prophylaxis using six-point single subject versus population-based method (WAPPS-Hemo) for simoctocog alfa (Nuwiq®). Methods: Twelve adult patients with severe haemophilia A received a factor VIII (FVIII) dose of ≈50 IU/kg, and the activity was measured pre-infusion and at 30 min, 6, 9, 24 and 48 h post-infusion. Half-life (t1/2), weight-normalized AUC and time to troughs of 5%, 3% and 1% were calculated. The correlation between the PK algorithms was assessed using intraclass correlations (ICC) and dosing estimations were provided. Results: WAPPS-Hemo yielded a slightly longer mean t1/2, but the overall correlation between the methods was good (ICC ≥0.79) The time to troughs of 5%, 3% and 1% showed ICCs ≥0.86. For all variables, the most converging limited time point was 6+48 h. Additional time points did not improve the correlation. Despite similar pharmacokinetics, the mean estimated dose for a specific trough level varied from 60% less to 20% more using the population-based approach. The time to 1% and the corresponding dose was sensitive to the baseline assumption. Conclusion: Our data support the use of population-based PK for patients on simoctocog alfa prophylaxis but also indicates differences, stressing the importance of the sampling scheme and monitoring actual FVIII levels achieved.
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