DDAVP responsiveness in children with mild or moderate haemophilia A correlates with age, endogenous FVIII:C level and with haemophilic genotype

Genotype-Dependent Response to Desmopressin in Hemophilia A and Proposal of a Predictive Response Score

BACKGROUND

 Desmopressin (DDAVP) is used in patients with moderate/mild hemophilia A (PWMHs) to increase their factor VIII (FVIII) level and, if possible, normalize it. However, its effectiveness varies between individuals. The GIDEMHA study aims to investigate the influence of F8 gene variants.

MATERIAL AND METHODS

 The study collected the trajectory of FVIII levels from therapeutic intravenous DDAVP tests in four French hemophilia treatment centers. A pharmacological analysis was performed associated with efficacy scores according to F8 variants: absolute and relative responses, as well as new scores: absolute duration (based on duration with FVIII ≥ 0.50 IU.mL-1) and relative duration (based on half-life).

RESULTS

 From enrolled 439 PWMHs, 327 had a hot-spot F8 variant (with ≥5 PWMHs). For these, the median (min-max) basal and peak FVIII were 0.20 (0.02-0.040) and 0.74 (0.14-2.18) IU.mL-1 respectively, with FVIII recovery being 3.80 IU.ml-1 (1.15-14.75). The median FVIII half-life was 3.9 hours (0.7-15.9 hours). FVIII was normalized (≥0.50 IU.mL-1) in 224/327 PWMHs (69%) and the median time with normalized FVIII was 3.9 hours (0.0-54.1 hours). Following the response profiles to DDAVP defined by the four efficacy scores, four groups of F8 variants were isolated, and then compared using survival curves with normalized FVIII (p < 0.0001): "long-lastingly effective" [p.(Glu739Lys), p.(Ser2030Asn), p.(Arg2178His), p.(Gln2208Glu), and T-stretch deletion in intron 13]; "moderately effective" [p.(Ser112Phe), p.(Ala219Thr), p.(Thr2105Ile), p.Phe2146Ser), and p.(Asp2150Asn)]; "moderately ineffective" [p.Ala81Asp), p.(Gln324Pro), p.(Tyr492His), p.(Arg612Cys), p.(Met701Val), p.(Val2035Asn), and p.(Arg2178Cys)]; and "frequently ineffective" [c.-219C > T, p.(Cys2040Tyr), p.(Tyr2169His), p.(Pro2319Leu), and p.(Arg2326Gln)].

CONCLUSION

 In view of our data, we propose indications for DDAVP use in PWMH based on F8 variants for minor and major invasive procedures.

Unravelling the effect of blood group on FVIII:C levels and response to DDAVP in 20 males with a single genotype (Twillingate Variant) causing Haemophilia A

INTRODUCTION

The genetic variant responsible for haemophilia A (HA) significantly impacts endogenous coagulant factor VIII (FVIII:C) level, thus impacting DDAVP responsiveness. Blood group (BG) also impacts FVIII:C levels, but this is difficult to evaluate in a genetically heterogeneous population. Canada has a large cohort of mild-moderate HA due to a single point variant: c.6104T>C, p.Val2035Ala-the Twillingate variant.

AIM

To evaluate the impact of BG on endogenous FVIII:C levels and DDAVP responsiveness in a single genotype of mild-moderate HA.

METHODS

This was a retrospective, single-centre study. BG and FVIII:C levels were obtained for males with the Twillingate variant. One-hour absolute and fold increases in FVIII:C post-DDAVP were calculated. T-tests and Mann-Whitney U tests were used to compare FVIII:C levels and DDAVP challenge variables between individuals according to BGs (O vs. non-O).

RESULTS

Twenty males were included. There were significant differences between BGs (O vs. non-O) in their lowest FVIII:C level at age <12 years (medians: 0.05 vs. 0.08 IU/mL; P = .05). Fifteen subjects underwent DDAVP challenges. Mean 1-h FVIII:C were 0.29 (O BG) versus 0.41 IU/mL (non-O BG); P = .04. There were no significant differences between BGs (O vs. non-O) in mean absolute FVIII:C increase (0.20 vs. 0.27 IU/mL; P = .10) and FVIII:C fold increase (3.3-fold vs. 3.8-fold; P = .51).

CONCLUSION

In HA subjects with an identical genotype, BG significantly impacts baseline FVIII:C levels and FVIII:C levels post-DDAVP, but does not impact absolute and fold increases in FVIII:C with DDAVP.

Prophylaxis use of clotting factor replacement products in people with non-severe haemophilia: A review of the literature

INTRODUCTION

People with non-severe haemophilia appear to be under-treated in many countries, and this may lead to joint damage and worsen quality of life.

AIM

To review literature for clotting factor replacement prophylaxis in people with non-severe haemophilia A and B (HA/HB) in relation to long-term outcomes to support clinical decision-making.

METHODS

A targeted literature search was performed to identify studies published between 2000 and 2021 that included prophylaxis in people with non-severe HA/HB and long-term outcomes, including annualized bleeding rates, joint health and quality of life.

RESULTS

Although eligible articles included 2737 and 2272 people with mild or moderate HA, respectively, only 22% (n = 609) and 29% (n = 668) reported treatment regimens. A total of 549 people with moderate HA were treated with factor replacement prophylaxis and were from high-income countries. On the contrary, nearly all people with mild HA received desmopressin (n = 599). Details of treatment regimens for women with haemophilia and people with HB were sparse. Three studies provided long-term outcomes for people with moderate haemophilia who received prophylaxis with factor concentrate, supporting early prophylaxis in people with a frequent bleeding phenotype regardless of their endogenous clotting factor level to preserve joint health.

CONCLUSION

There remain large knowledge gaps when considering how to provide optimal treatment for people with non-severe haemophilia. Nonetheless, there is a strong rationale that prophylaxis should be considered early in life according to similar strategies as for severe haemophilia for those with a frequent severe bleeding phenotype.

Moderate-intensity aerobic exercise vs desmopressin in adolescent males with mild hemophilia A: a randomized trial

Persons with mild hemophilia A (HA) may use intranasal desmopressin prior to sports participation. Desmopressin is expensive and can cause vomiting, headache, palpitation, and occasionally seizures. Our group has previously documented a 2.3-fold increase in factor VIII activity (FVIII:C) in adolescents with mild HA after moderate-intensity aerobic exercise. Herein, we report principal findings of a randomized trial of intranasal desmopressin vs a standardized, moderate-intensity aerobic exercise regimen in adolescents with mild HA. Our primary objective was to compare the change in FVIII:C associated with these 2 interventions. We also examined changes in hemostatic parameters arising from their sequential administration. The study was conducted simultaneously at the Hospital for Sick Children, Canada, and Nationwide Children's Hospital, USA. Thirty-two eligible male adolescents (mean age ± standard deviation: 16.1 ± 2.6 years) with mild HA (mean baseline FVIII:C: 27.9% ± 18.4%) were randomized to 1 of 4 study arms (desmopressin followed by exercise, desmopressin alone, exercise followed by desmopressin, and exercise alone). Blood work was obtained at baseline and at 3 subsequent time-points. Participants randomized to exercise cycled on an ergometer for approximately 12 minutes, with the final 3 minutes at 85% of their predicted maximum heart rate. Standard weight-based dosing of desmopressin was used. Mean immediate increase in FVIII:C was 1.7-fold with exercise compared with 1.9-fold with desmopressin (noninferiority, P = .04). Exercise-induced improvement in hemostatic parameters including FVIII:C was brief compared with more sustained improvements seen with desmopressin. More than 60% of participants randomized to receive both exercise and desmopressin achieved normal (>50%) FVIII:C, 75 and 135 minutes into the study protocol.

Desmopressin for bleeding in non‐severe hemophilia A: Suboptimal use in a real‐world setting

Background

Desmopressin is an important treatment option in nonsevere hemophilia A because it has several benefits compared with factor (F) concentrates, including no inhibitor risk and much lower costs. Despite these advantages, data are limited on the real‐world use of desmopressin in the treatment of bleeds.

Objective

To describe the clinical use of desmopressin in relation to other therapeutic modalities in the treatment of bleeding episodes in patients with nonsevere hemophilia A.

Methods

Patients with nonsevere hemophilia A aged 12–55 years were included from the DYNAMO cohort study. Data on the desmopressin test response and treated bleeding events in the period January 2009 to July 2020 were retrospectively collected from medical files. An adequate desmopressin test response was defined based on a peak FVIII level of ≥30 IU/dl.

Results

A total of 248 patients with a median age of 38 years (interquartile range 25–49) were included. An adequate desmopressin test response was documented in 25% and 73% of patients with moderate and mild hemophilia, respectively. In adequate responders, 51% of bleeds were exclusively treated with FVIII concentrates, 24% exclusively with desmopressin, 21% with a combination of both and 4% with other treatments. In 54% of bleeds treated with a single dose of factor concentrates, the expected FVIII level after desmopressin exceeded the level targeted.

Conclusion

Most bleeds in patients with an adequate response to desmopressin are treated with factor concentrates. These findings may indicate a suboptimal use of desmopressin and that barriers to the use of desmopressin should be explored.

Novel F8 and F9 gene variants from the PedNet hemophilia registry classified according to ACMG/AMP guidelines

In hemophilia A and B, analysis of the F8 and F9 gene variants enables carrier and prenatal diagnosis and prediction of risk for the development of inhibitors. The PedNet Registry collects clinical, genetic, and phenotypic data prospectively on more than 2000 children with hemophilia. The genetic reports of F8/F9 gene variants were classified uniformly to Human Genome Variation Society nomenclature and reevaluated using international population‐ and disease‐specific databases, literature survey and, where applicable, computational predictive programs. We report 88 novel variants in the F8 and F9 genes, 80 fulfilling criteria for Class 5 (pathogenic), six for Class 4 (likely pathogenic) and two fulfilling criteria for Class 3 (variant of unknown significance) of the American College of Medical Genetics and Genomics/Association for Molecular Pathologyguidelines together with information on the respective phenotype and inhibitor formation. The study highlights the need to reevaluate and update earlier genetic reports in hemophilia both locally but also in variant databases in light of changed nomenclature and new guidelines.

Desmopressin in non-severe haemophilia A: Test-response and clinical outcomes in a single Canadian centre review

INTRODUCTION

Desmopressin is an effective haemostatic agent for patients with non-severe haemophilia A; however, response may differ between patients of similar severity. Responsiveness is classified based on various cut-off values for plasma levels of FVIII post-desmopressin administration. Patients may be classified differently depending on the values chosen.

AIM

To classify desmopressin response in non-severe haemophilia A patients with respect to current test-response definitions. Also, to characterize relationships between test response and clinical outcome of desmopressin use.

METHODS

Current desmopressin test-response definitions were obtained from the literature. We adopted peak FVIII level (at 1 hour post-administration) ≥50 IU/dL and <20 IU/dL as complete and no response, respectively, thereby satisfying most reported definitions. Test-responses and clinical outcomes of use between 2007 and 2017 for adult mild/moderate haemophilia A patients were reviewed and correlated.

RESULTS

All patients classified as complete responders (n = 31; peak FVIII ≥50 IU/dL) and the majority of partial responders (n = 11; peak FVIII ≥20 to <50 IU/dL) had good clinical outcomes after desmopressin use for a variety of bleeding episodes and procedures. Two non-responders (peak FVIII <20 IU/dL) given desmopressin for minor bleeding/procedures also had good clinical outcomes. One patient with a partial test-response (peak FVIII 23 IU/dL) required additional factor concentrate to achieve haemostasis.

CONCLUSIONS

Based on our review, we suggest that the determination of desmopressin responsiveness should consider both the change in plasma FVIII levels as well as clinical outcomes associated with prior therapeutic use.

Genotypes, phenotypes and whole genome sequence: Approaches from the My Life Our Future haemophilia project

INTRODUCTION

Information from the genes encoding factor VIII (F8) and IX (F9) is used in reproductive planning and to inform inhibitor formation, bleeding severity and response to therapies. Advances in technology and our understanding of the human genome now allows more comprehensive methods to study genomic variation and its impact on haemophilia.

AIMS

The My Life Our Future (MLOF) programme was begun in 2012 to provide genetic analysis and to expand research in haemophilia through a research repository.

METHODS

MLOF enrolled haemophilia A and B patients followed at haemophilia treatment centers in the U.S., including, since 2015, known and potential genetic carriers. Initial F8 and F9 DNA analysis was performed utilizing a next generation sequencing approach which allowed simultaneous detection of F8 inversions and other variants. Candidate variants were confirmed using a second method and multiplex ligation-dependent probe amplification was used to detect structural variants.

RESULTS

The initial phase of MLOF completed enrollment in December 2017 with 11,356 patients, genetic carriers, and potential carriers enrolled. In the 9453 subjects in whom analysis is complete, 687 unique previously unreported variants were found. Simultaneous sequencing of the F8 and F9 genes resulted in identification of non-deleterious variants previously reported as causative in haemophilia. DNA from 5141 MLOF subjects has undergone whole genome sequencing through the NHLBI TOPMed programme of the U.S. NIH.

CONCLUSION

MLOF has provided genetic information for patients and their families to help inform clinical care and has established a repository of data and biospecimens to further advance haemophilia research.

Desmopressin in moderate hemophilia A patients: a treatment worth considering

Desmopressin increases endogenous factor VIII levels in hemophilia A. Large inter-individual variation in the response to desmopressin is observed. Patients with a lower baseline factor VIII activity tend to show a reduced response, therefore, desmopressin is less frequently used in moderate hemophilia A patients (baseline factor VIII activity 1-5 international units/deciliter), even though factor VIII levels may rise substantially in some of them. We aim to describe the response to desmopressin in moderate hemophilia A patients and to identify predictors. We selected data on 169 patients with moderate hemophilia from the multicenter Response to DDAVP In non-severe hemophilia A patients: in Search for dEterminants (RISE) cohort study. Adequate response to desmopressin was defined as a peak factor VIII level ≥ 30, and excellent response as ≥ 50 international units/deciliter after desmopressin administration. We used univariate and multiple linear regression techniques to analyze predictors of the peak factor VIII level. Response was considered adequate in 68 patients (40%), of whom 25 showed excellent response (15%). Intravenous administration, age, pre-desmopressin factor VIII activity and von Willebrand factor antigen, peak von Willebrand factor activity and desmopressin-induced rise in von Willebrand factor antigen were significant predictors of peak factor VIII level and explained 65% of the inter-individual variation. In 40% of moderate hemophilia A patients, desmopressin response was adequate, thus it is important not to with-hold this group of patients from desmopressin responsiveness. Among the six predictors that we identified for desmopressin-induced factor VIII rise, factor VIII activity and desmopressin-induced rise in von Willebrand factor antigen had the strongest effect.

Desmopressin testing in haemo-philia A patients and carriers

Introduction: Desmopressin (DDAVP) testing (DT) in patients (pts) with haemophilia A (HA) and carriers (CHA) is up to now not standardized. This prompted us to evaluate results of DT carried out between 1996 and 2011 in centres of the Competence Network Haemor-rhagic Diatheses East. Patients and method: An increase of the factor VIII activity (FVIII) above 50% or at least the two fold of initial values within 120 min after DDAVP was defined as complete response (CR). Data from 80 patients (31 children, 49 adults) of whom 64 suffered from HA (sub-HA: n = 48; mild: n = 14; moderate: n = 2) and 16 patients CHA were evaluated. Results: In 34 patients DDAVP was given i. v. (dose range: 0.26–0.6 μg/kg body weight, mean: 0.33), in 31 intranasally (i.n. 300–600 μg) and in 15 s. c. (15–40 μg). The maximal FVIII increase was reached 60 min after DDAVP. For i. v. application the mean FVIII increase was 3.1-fold, for i. n. 2.1-fold and for s. c. 2.4-fold. A CR was de tected in 71 patients, a non-response in 9. Mild side effects such as flush, headaches or nausea were observed in 11 patients (14%). Conclusion: For desmopressin testing in patients with haemophilia A and carriers i. v. application at 0.3 μg/kg body weight and the determination of FVIII before and 60 min after desmopressin infusion is recommended.

Response to desmopressin is strongly dependent on F8 gene mutation type in mild and moderate haemophilia A

Desmopressin causes two- to six-fold increase of factor VIII (FVIII) in mild or moderate haemophilia A patients. However, responses are variable and little is known whether this is associated with F8 gene mutation. The study objective was to assess the relationship between F8 gene mutation and desmopressin response in haemophilia A patients. Desmopressin response (absolute and relative) was determined in 97 hemophilia A patients. Four amino acid changes (Arg2169His, Pro149Arg, Asn637Ser, and Arg612Cys) and a number of other mutations leading to an aberrant FVIII protein or FVIII deficiency were analysed. Patients with Arg2169His showed significantly lower FVIII levels before and after desmopressin compared to all other mutations (p<0.001). Pro149Arg amino acid change showed significantly lower FVIII levels 1 hour after desmopressin compared to all other mutations (p<0.005). An absolute response with FVIII ≥0.50 IU/ml after 1 hour was observed in 41% (9 of 22) of patients with Arg2169His; however, this was not sustainable after 6 hours in any of these subjects. No patients with Pro149Arg mutation (n=6) showed an absolute response with FVIII _0.50 IU/ml. Patients with other mutations showed significantly more complete and partial responses. Relative responses did not differ between mutations. Our study shows that haemophilia A patients with amino acid change Arg2169His or Pro149Arg have a decreased desmopressin response with regard to FVIII levels as compared to other mutations. Our results indicate that response to desmopressin is dependent on the F8 gene mutation type, despite the fact that multiple factors influence the desmopressin response, even within families.

Impact of aerobic exercise on haemostatic indices in paediatric patients with haemophilia

This study investigated the impact of aerobic exercise on laboratory assessments of haemostatic activity in boys (5–18 years of age) with haemophilia A (HA) or B (HB), examining the hypothesis that laboratory coagulation parameters temporarily improve with exercise. Thirty subjects meeting eligibility criteria (19 HA; 11 HB; mean age: 12.8 years) were invited to participate. They underwent a replacement factor washout period and were advised against strenuous activity for three days prior to the planned intervention. At study visit, baseline blood samples were drawn prior to exercise on a stationary cycle ergometer, aiming to attain 3 minutes (min) of cycling at 85 % of predicted maximum heart rate. Blood work was repeated 5 min (t5) and 60 min (t60) post exercise completion. Samples were assessed for platelet count (PC), factor VIII activity (FVIII:C), von Willebrand antigen (VWF:Ag), ristocetin cofactor activity (VWF:RCo) and platelet function analysis (PFA-100); maximum rate of thrombus generation (MRTG) in blood was measured via thromboelastography and plasma peak thrombin generation (PTG) via calibrated automated thrombography. Mean duration of exercise was 13.9 (± 2.6) min. On average, t5 samples showed significant elevation, relative to baseline in PC, FVIII:C, VWF:Ag, VWF:RCo and PTG, while FVIII:C, VWF:Ag, VWF:RCo and MRTG were significantly elevated in t60 samples. Within the cohort, participants with severe HA showed no change in FVIII:C levels with exercise. The greatest improvement in haemostatic indices was observed in post-adolescent males with mild-moderate HA, who thus represent the group most likely to benefit from a reduction of bleeding risk in the setting of exercise.

Diagnosis and care of patients with mild haemophilia: practical recommendations for clinical management

Mild haemophilia is defined by factor levels between 0.05 and 0.40 IU/mL and is characterised by traumatic bleeds. Major issues associated with mild haemophilia are that it may not present for many years after birth, and that awareness, even within families, may be low. Methodological problems exist in diagnosis, such as inconsistencies in results obtained from different assays used to measure factor levels in mild haemophilia. Advances in genetic testing provide insight into diagnosis as well as the likelihood of inhibitor development, which is not uncommon in patients with mild or moderate haemophilia and can increase morbidity. The management of patients with mild haemophilia is a challenge. This review includes suggestions around formulating treatment plans for these patients, encompassing the full spectrum from clinical care of the newly diagnosed neonate to that of the ageing patient with multiple comorbidities. Management strategies consider not only the vast differences in these patients' needs, but also risks of inhibitor development and approaches to optimally engage patients.

Current and Emerging Options for the Management of Inherited von Willebrand Disease

Von Willebrand disease (VWD) is the most common inherited bleeding disorder with an estimated prevalence of ~1% and clinically relevant bleeding symptoms in approximately 1:10,000 individuals. VWD is caused by a deficiency and/or defect of von Willebrand factor (VWF). The most common symptoms are mucocutaneous bleeding, hematomas, and bleeding after trauma or surgery. For decades, treatment to prevent or treat bleeding has consisted of desmopressin in milder cases and of replacement therapy with plasma-derived concentrates containing VWF and Factor VIII (FVIII) in more severe cases. Both are usually combined with supportive therapy, e.g. antifibrinolytic agents, and maximal hemostatic measures. Several developments such as the first recombinant VWF concentrate, which has been recently licensed for VWD, will make a more "personalized" approach to VWD management possible. As research on new treatment strategies for established therapies, such as population pharmacokinetic-guided dosing of clotting factor concentrates, and novel treatment modalities such as aptamers and gene therapy are ongoing, it is likely that the horizon to tailor therapy to the individual patients' needs will be extended, thus, further improving the already high standard of care in VWD in most high-resource countries.

Desmopressin in haemophilia: The need for a standardised clinical response and individualised test regimen

INTRODUCTION

Due to interindividual variation in desmopressin response, non-severe haemophilia A patients require desmopressin testing prior to therapeutic treatment. However, adequate response or frequency of blood sampling is not standardised in international guidelines. Consequently, various definitions and blood sampling protocols are currently applied. Interestingly, sustainability of desmopressin response is not incorporated into these definitions.

AIM

To study desmopressin response rates in a cohort of non-severe haemophilia A patients using currently accepted desmopressin response definitions. This, in order to formulate a standardised, uniform response which includes information on sustainability and to design a standardised blood sampling protocol.

METHODS

Currently used desmopressin responses in non-severe haemophilia A patients were derived from a literature search. Actual desmopressin response rates were individualised in 105 non-severe HA patients from the Erasmus University Medical Centre and classified according to current varying definitions.

RESULTS

Five response definitions were evaluated, three of which included only factor VIII (FVIII):C cut-off levels and two also incorporated FVIII:C-fold increase over baseline.

FVIII

C-fold increase showed no association with desmopressin response sustainability.

FVIII

C 1 hour after infusion (<0.30, ≥0.30-0.49, ≥0.50-0.79 and ≥0.80 IU/mL) was, however, indicative of desmopressin response after 6 hours.

CONCLUSION

We suggest standardised desmopressin response based on clinically relevant FVIII:C levels, e.g. 0.30 and 0.50 IU/mL. In addition, patients with <0.30 IU/mL FVIII:C after 1 hour (non-responder) or ≥0.80 IU/mL (sustained responder) do not require subsequent blood sampling. However, patients with ≥0.30-0.79 IU/mL FVIII:C after 1 hour should undergo blood sampling after 6 hours to additionally determine response sustainability.

Outcomes in Patients With Hemophilia and von Willebrand Disease Undergoing Invasive or Surgical Procedures

Adults with hemophilia A (HA), hemophilia B (HB), and von Willebrand disease (VWD) frequently require surgery and invasive procedures. However, there is variability in perioperative management guidelines. We describe our periprocedural outcomes in this setting. A retrospective chart review from January 2006 to December 2012 of patients with HA, HB, and VWD undergoing surgery or invasive procedures was conducted. Type of procedures, management including the use of continuous factor infusion, and administration of antifibrinolytics were reviewed. Adverse outcomes were defined as acute bleeding (<48 hours), delayed bleeding (≥48 hours), transfusion, inhibitor development, and thrombosis. We identified 59 patients with HA and HB. In all, 24 patients had severe hemophilia and 12 had mild/moderate hemophilia. Twelve patients had inhibitors. There were also 5 female carriers of HA and 6 patients with VWD. There were 34 major surgeries (26 orthopedic, 8 nonorthopedic) and 129 minor surgeries. Continuous infusion was used in 55.9% of major surgeries versus 8.5% of minor surgeries. Antifibrinolytics were administered in 14.7% of major surgeries versus 23.2% of minor surgeries. In all, 4 patients developed acute bleeding and 10 patients developed delayed bleeding. Delayed bleeding occurred in 28.6% of genitourinary procedures and in 16.1% of dental procedures. Five patients acquired an inhibitor and 2 had thrombosis. In conclusion, patients with HA, HB, or VWD had similar rates of adverse outcomes when undergoing minor surgeries or major surgeries. This finding underscores the importance of an interdisciplinary management and procedure-specific guidelines for patients with hemophilia and VWD prior to even minor invasive procedures.

Update on inherited disorders of haemostasis and pregnancy

Inherited bleeding disorders have the potential to cause bleeding complications during pregnancy, childbirth and the postpartum period as well as effect fetal outcomes. There is an evolving understanding of the need for specialised and individualised care for affected women during these times. The aim for each patient is to estimate the risk to mother, fetus and neonate; to implement measures to minimise these risks; and to anticipate complications and develop contingencies for these scenarios. This includes accurate diagnosis, preconceptual care, prenatal diagnostic options, antenatal care, delivery and postpartum care as well as care of an affected neonate. An understanding of the physiologic haemostatic changes associated with pregnancy as well as the scope of defects, inheritance and management of inherited bleeding disorders is paramount when caring for these women. Collaborative and prospective management in conjunction with haematology services underpins the approach advocated. This review draws on the available literature, and outlines the principles of care for women with inherited bleeding disorders before, during and after pregnancy, as well as their babies, based on both available data and collective clinical experience.

Desmopressin responsiveness at a capped dose of 15 μg in type 1 von Willebrand disease and mild hemophilia A

Desmopressin (DDAVP) is commonly used in the treatment of patients with type 1 von Willebrand disease (VWD) and mild hemophilia A. A patient's responsiveness to DDAVP based on a 0.3  μg/kg dose determines future therapeutic efficacy of the drug. The aim of the study was to determine whether a capped dose of 15 μg subcutaneous DDAVP is able to achieve the same level of DDAVP responsiveness as previously reported. This is a retrospective chart review of patients from 1995 to 2013 in adults and children with type 1 VWD and hemophilia A weighing more than 50 kg. Levels of factor VIII, ristocetin cofactor, and von Willebrand factor antigen were measured before and after 1 h of administration of 15 μg of DDAVP. In patients with type 1 VWD, the complete response rate was 82.5% with a partial response rate of 12.5% and 5% nonresponders. In patients with mild hemophilia A, the complete response rate was 53.8% with a partial response rate of 38.5% and 7.7% nonresponders. These results using a capped 15-μg dose of DDAVP are similar to previously published reports using the 0.3-μg/kg dose.

Side effects of desmopressin in patients with bleeding disorders

INTRODUCTION

Desmopressin is frequently used in patients with bleeding disorders because of its prohaemostatic effects. In recent years desmopressin use increased due to reported high incidence of inhibitors in mild haemophilia after clotting factor infusion and the rising costs of clotting factor concentrates. The safety and frequency of side effects have hardly been assessed in well-designed studies.

AIM

We therefore prospectively evaluated side effects of desmopressin in a large unselected cohort of bleeding disorder patients, who received a desmopressin test dose.

METHODS

Blood was drawn prior to, one, three, six and 24 h after desmopressin. Primary outcome was change in serum sodium, haematocrit, serum- and urine osmolality, body weight and vital signs. Self-reported side effects were evaluated as secondary outcome.

RESULTS

In total, 108 patients were included, median age 30 years, the majority of whom had von Willebrand disease type 1 (76%). A significant change in water balance parameters was observed. Four patients (4%) had hyponatraemia (≤135 mmol L(-1) ) after 24 h but no severe hyponatraemia occurred (≤125 mmol L(-1) ). After infusion, 41 (38%) patients were hypotensive (≤90 mmHg SBP and/or ≤60 mmHg DBP) and 10 (9%) presented with tachycardia (>100 min(-1) ). However, none of these effects sustained at 24 h. Infusion was discontinued in one patient because of tachycardia, nausea and malaise. Self-reported side effects included: headache, fatigue, flush and dizziness.

CONCLUSION

Observed side effects correspond with the known antidiuretic and vasomotor effects of desmopressin. Changes in parameters were temporary and not clinically relevant. In conclusion, our study supports desmopressin use as a safe treatment option in patients with various bleeding disorders.

Molecular and clinical predictors of inhibitor risk and its prevention and treatment in mild hemophilia A

The risk for inhibitor development in mild hemophilia A (factor VIII levels between 5 and 40 U/dL) is larger than previously anticipated, continues throughout life, and is particularly associated with certain mutations in F8. Desmopressin may reduce inhibitor risk by avoiding exposure to FVIII concentrates, but the heterogenous biological response to desmopressin, showing large interindividual variation, may limit its clinical use. However, predictors of desmopressin response have been recently identified, allowing the selection of the best candidates to this treatment.

Inherited abnormalities of coagulation: hemophilia, von Willebrand disease, and beyond

Bleeding disorders are broadly classified into primary and secondary hemostatic defects. Primary hemostatic disorders (disorders of platelets and von Willebrand factor) mainly result in mucocutaneous bleeding symptoms such as epistaxis, menorrhagia, petechiae, easy bruising, and bleeding after dental and surgical interventions. Secondary hemostatic disorders (congenital or acquired deficiencies of coagulation factors) typically manifest with delayed, deep bleeding into muscles and joints. This article provides a generalized overview of the pathophysiology, clinical manifestations, laboratory abnormalities, and molecular basis of inherited abnormalities of coagulation with a focus on hemophilia, von Willebrand disease, and rare inherited coagulation disorders.

The use of DDAVP in children with bleeding disorders

Desmopressin (1-deamino-8-D-arginine vasopressin, DDAVP) has been used in children with von Willebrand disease (VWD) and Hemophilia A for almost 35 years. This treatment has substantially lowered the number of children exposed to human plasma derived products, with a good safety profile, and at very low cost. The response to DDAVP has been shown to be associated with age, baseline factor level, and genetic mutations. A DDAVP challenge test is recommended. DDAVP has also been used to prevent and treat bleeding episodes in children with platelet function defects and other disorders associated with bleeding tendency.

The hemophilias and their clinical management

Outcomes for patients with hemophilia have improved dramatically over the past 50 years. With the increased availability of safe clotting factor concentrates, the primary focus in clinical management is now the prevention of long-term complications, most notably the debilitating hemophilic arthropathy that is associated with severe disease. This article reviews evidence-based approaches for managing both children and adults with hemophilia. Definitive evidence of improved clinical results from primary prophylaxis started in young patients with severe hemophilia A and a minimal bleeding history is presented. Furthermore, recent studies showing benefits for initiating prophylaxis in older adolescents and adults with established joint disease are examined. Inhibitors to factor VIII are the most problematic complication of factor replacement therapy. Patient-specific and treatment-related factors that contribute to the risk of inhibitor formation are discussed and controversies and clinical evidence related to approaches for tolerance induction are reviewed.