Safety and efficacy of BAY 94-9027, a prolonged-half-life factor VIII

Essentials Recombinant factor VIII BAY 94-9027 conjugates in a site-specific manner with polyethylene glycol. BAY 94-9027 was given to patients with severe hemophilia A as prophylaxis and to treat bleeds. BAY 94-9027 prevented bleeds at dose intervals up to every 7 days and effectively treated bleeds. BAY 94-9027 treatment was mainly well tolerated and no patient developed factor VIII inhibitors. Click to hear Dr Tiede's perspective on half-life extended factor VIII for the treatment of hemophilia A SUMMARY: Background BAY 94-9027 is a B-domain-deleted prolonged-half-life recombinant factor VIII (FVIII) that conjugates in a site-specific manner with polyethylene glycol. Objective Assess efficacy and safety of BAY 94-9027 for prophylaxis and treatment of bleeds in patients with severe hemophilia A. Patients/methods In this multinational, phase 2/3, partially randomized, open-label trial, men aged 12-65 years with FVIII < 1% and ≥ 150 exposure days to FVIII received BAY 94-9027 for 36 weeks on demand or prophylactically at intervals determined following a 10-week run-in period on 25 IU kg-1 body weight two times per week. Patients with > 1 bleed during the run-in subsequently received 30-40 IU kg-1 two times per week; patients with ≤ 1 bleed were eligible for randomization to every-5-days (45-60 IU kg-1 ) or every-7-days (60 IU kg-1 ) prophylaxis (1 : 1) for 26 additional weeks until randomization arms were filled. Patients who were eligible but not randomized continued twice-weekly prophylaxis. The primary efficacy outcome was annualized bleeding rate (ABR). Results The intent-to-treat population included 132 patients (prophylaxis, n = 112; on demand, n = 20). Median ABR (quartile [Q1; Q3]) for patients treated two times per week who were not eligible for randomization (n = 13) improved after dose increase (17.4 [14.3; 26.0] to 4.1 [2.0; 10.6]). Median ABR for patients randomized to every-5-days treatment (n = 43) was 1.9 (0; 4.2), similar to patients eligible for randomization but who continued treatment two times per week (n = 11). Median ABR for 32/43 patients (74%) who continued every-7-days prophylaxis until study end was 0.96 (0.0; 4.3). Six hundred and thirty-six of 702 bleeds (90.6%) were controlled with ≤ 2 infusions. No patient developed a FVIII inhibitor. Conclusions BAY 94-9027 prevented bleeding across three individually tailored dose regimens and was effective for treatment of bleeds.

Baby hamster kidney cell-derived recombinant factor VIII: a quarter century of learning and clinical experience

INTRODUCTION

Management and care of individuals with hemophilia A advanced immensely with the introduction of recombinant factor VIII (rFVIII) replacement products. This review provides a historical overview of rFVIII development with a focus on Bayer's rFVIII (with albumin) and sucrose-formulated rFVIII (rFVIII-FS), the only rFVIII products cloned in baby hamster kidney (BHK) cells with >25 years of proven safety and efficacy. Areas covered: We review the advances in rFVIII technology and the efficacy and safety data for BHK-derived rFVIII/rFVIII-FS from clinical trials, investigator-initiated studies, and observational studies. Innovative products with new treatment potentials (eg, BAY 81-8973 and BAY 94-9027) built on this established safety and efficacy profile are also briefly discussed. The literature search strategy included targeted searches (PubMed) with manual article selection and other product-specific searches. Expert commentary: Development of rFVIII products and related improvements in viral safety and manufacturing efficiency have guaranteed an adequate supply of factor products worldwide and increased prophylaxis use. The net effects have been joint health preservation, reduction in morbidity and mortality, and quality-of-life enhancements. Current treatment challenges include lack of adherence to prophylaxis and inhibitor development; extended-half-life rFVIII products and non-FVIII replacement therapies in development may help overcome these challenges.

An overview of current trends and gaps in patient-reported outcome measures used in haemophilia

AIM

This review summarises the importance, recent progress and issues in measuring patient-reported outcomes (PROs) in haemophilia research.

METHODS

A critical review of recent advances and trends in measuring haemophilia-related PROs was conducted, using current regulatory guidelines and methodological recommendations to evaluate these instruments.

RESULTS

Although regulators, payers and policymakers increasingly consider the patient's perspective to be important in treatment decision-making, to date, few haemophilia intervention studies have meaningfully applied PRO endpoints. Condition-specific PRO instruments have been developed, but most are not fully validated; sensitivity to subgroup differences and changes over time is unclear. Generic PROs and instruments developed for other conditions have been used to measure health-related quality of life (HRQL) in haemophilia patients, but little evidence of their validity for this purpose exists. Haemophilia presents a number of challenges to developing valid, reliable and responsive PRO instruments, including the rarity of the disorder; necessitating research in multiple counties to attain sufficient sample size; the chronic nature of the condition; acute exacerbations of illness; age and geographical region variations with respect to treatment; differences in treatment regimens, range of disease severity and phenotypes; and changes in patients' perceived health status over time. Given that haemophilia begins at birth, the illness has an impact on the lives of caregivers, although the extent of the impact is largely unknown.

CONCLUSIONS

Patient perspectives are crucial to understanding the best and most cost-effective haemophilia treatment approaches. More research is needed on the ability of current disease-specific and generic PRO instruments to capture responsiveness to treatments over time and subgroup differences in outcomes. Inclusion of PROs in clinical trials is necessary to answer these questions.

Phase I study of BAY 94-9027, a PEGylated B-domain-deleted recombinant factor VIII with an extended half-life, in subjects with hemophilia A

BACKGROUND

BAY 94-9027 is a B-domain-deleted recombinant factor VIII (rFVIII) with site-specific attachment of poly(ethylene glycol) that has shown an extended half-life in animal models of hemophilia.

OBJECTIVES

To assess the pharmacokinetics and safety of BAY 94-9027 after single and repeated administration in subjects with severe hemophilia A.

PATIENTS/METHODS

This 8-week, prospective, multicenter, open-label, phase I trial was conducted in 14 subjects aged 21–58 years with FVIII of < 1%, ≥ 150 days of exposure to FVIII, and no history of FVIII inhibitors. After a ≥ 3-day washout, subjects received a single dose of sucrose-formulated rFVIII (rFVIII-FS) (cohort 1 [n = 7], 25 IU kg−1; cohort 2 [n = 7], 50 IU kg−1) for a 48-h pharmacokinetic (PK) study. After another ≥ 3-day washout, cohort 1 received twice-weekly BAY 94-9027 at 25 IU kg−1 (16 doses), and cohort 2 received once-weekly BAY 94-9027 at 60 IU kg−1 (nine doses). A 168-h PK study was performed after the first and last BAY 94-9027 doses.

RESULTS

BAY 94-9027 showed equivalent recovery and an improved PK profile vs. rFVIII-FS, with a half-life of ~ 19 h (vs. ~ 13.0 h for rFVIII-FS). BAY 94-9027 was well tolerated, and no immunogenicity was observed.

CONCLUSIONS

This phase I study demonstrates that BAY 94-9027 has an extended half-life in subjects with hemophilia A and, after multiple dosing, was well tolerated with no immunogenicity during the 8-week trial. A phase III study in a larger number of subjects is underway to fully characterize how this prolonged half-life will permit less frequent prophylaxis dosing for patients with hemophilia.

An unusual presentation of May-Thurner syndrome in a pediatric patient with a pelvic kidney

We report a case of an adolescent who presented with a deep vein thrombosis (DVT) and clinical findings consistent with May-Thurner Syndrome. Specific imaging demonstrated direct compression of the left common iliac vein by an overlying pelvic kidney. The patient's history and clinical presentation is detailed. The discussion focuses on the potential implications for care and management of a patient with an ectopic left pelvic kidney.

Newly diagnosed immune thrombocytopenia in children and adults: a comparative prospective observational registry of the Intercontinental Cooperative Immune Thrombocytopenia Study Group

BACKGROUND

Primary immune thrombocytopenia is a bleeding diathesis with an unknown etiology in predisposed individuals with immune disturbances. Although it is claimed that children and adults differ in clinical and laboratory aspects, few data exist to corroborate this observation. Our objective was to assess comparative data from children and adults with newly diagnosed immune thrombocytopenia.

DESIGN AND METHODS

Clinical and laboratory data of 1,784 children and 340 adults were extracted from the Pediatric and Adult Registry on Chronic Immune Thrombocytopenia. The registry represents a prospective cohort of children and adults with newly diagnosed immune thrombocytopenia. Participating investigators registered their patients immediately after the diagnosis using a web based data transfer. Children aged under 16 years were compared with adults aged 16 years and over with descriptive statistical analyses.

RESULTS

The presenting mean platelet count of children and adults was 18.1 and 25.4 × 10(9)/L. Signs of bleeding were reported in 24% of children and in 23% of adults, and intracranial hemorrhage in 10 of 1,784 children and in 6 of 340 adults. Co-morbidity was observed in 3.9% of children and in 30% of adults. Bone marrow aspiration and laboratory tests (antinuclear antibodies, human immunodeficiency and hepatitis C virus) were performed more frequently in adults. Children and adults were followed with a 'watch and wait' strategy in 20% and in 29%, respectively. Immunoglobulins were used more frequently in children and corticosteroids in adults.

CONCLUSIONS

Comparative data of children and adults with newly diagnosed immune thrombocytopenia revealed similarities in presenting platelet counts and in bleeding, whereas differences occurred in co-morbidity, diagnostic procedures and therapy.

Psychosocial correlates of physical activity in adolescents with haemophilia

Boys with haemophilia are now encouraged to exercise and take part in physical activities, but actual measures of time spent in active participation is lacking. The aim of this study was to obtain an objective measure of daily physical activity in boys with haemophilia as compared with healthy controls. The study also aimed to ascertain the social and cognitive factors associated with exercise in this population. Seventeen patients (aged 11-18 years) with haemophilia were studied and compared with 44 healthy controls (aged 10-16.5 years). Physical activity was measured by accelerometry. Psychosocial correlates were assessed using validated questionnaires. Measured physical activity levels in subjects with haemophilia were slightly higher than for the control group. Both groups spent 70% of the day inactive, with similar proportions of time in moderate and vigorous activity. Subjects with haemophilia had a favourable self-image and similar levels of anxiety as peers without a bleeding disorder. Self-efficacy scores were lower than for controls suggesting increased sensitivity to barriers and lack of acceptance of alternatives. Health beliefs did not influence physical activity, but a negative correlation of time spent in high or vigorous activity with scores for support-seeking was observed. The data demonstrate that in the appropriate social environment and with medical support, patients with haemophilia may be as physically active as their peers without a bleeding disorder. Further investigation into the psychosocial barriers of physical activity in patients with haemophilia is needed to more effectively encourage healthy behaviours.

Deep venous thrombosis in adolescents due to anatomic causes

Aberrant or anomalous anatomy is an under appreciated risk for venous thromboembolic events (VTE). Five adolescents with VTE and predisposing anatomic abnormalities are presented. In three cases, knowledge of the underlying anatomic abnormalities resulted in changes in treatment and management. In two other cases, failure to consider or correct the underlying defect resulted in recurrent thrombosis or post-thrombotic complications. Few case reports are found in the pediatric literature, but a MEDLINE search across all age groups suggests these anomalies are frequently found when appropriate radiological imaging is obtained.

Prophylactic treatment of a small child with severe factor VII deficiency using repeat dosing from a single vial of recombinant activated factor VII

We report our experience with a small child with severe factor VII deficiency and a history of frequent and spontaneous life-threatening hemorrhage. The patient has received several years of successful prophylactic treatment with an every 3-day infusion program in which she receives recombinant activated factor VII (rVIIa) using multiple doses from a single reconstituted vial over a 72-hr period. Comparison is made to prophylactic treatment in this same patient using plasma-derived factor VII (PDVII) using a prothrombin complex concentrate (PCC).

The U.S. Thrombosis and Hemostasis Centers pilot sites program

Venous thromboembolism (VTE) is a common disorder associated with significant morbidity and mortality. Despite important advances in understanding the etiology of VTE, delivery of care to patients with thrombosis and thrombophilia is frequently incomplete and highly variable. A comprehensive model of health care has been used successfully to treat and prevent complications for people with hemophilia and other chronic disorders. The effectiveness of an integrated healthcare model for patients with all coagulation disorders has yet to be evaluated. The Division of Hereditary Blood Disorders of the Centers for Disease Control and Prevention (CDC) is collaborating with eight Thrombosis and Hemostasis Centers (pilot sites) to provide health-related services and conduct research directed toward the reduction or prevention of complications of thrombosis and thrombophilia. The initial objectives of the collaboration are to (1) determine the efficacy of integrated multidisciplinary care and prevention services for people with hemostatic disorders, (2) assess unmet needs for service delivery and identify outreach strategies to improve access to care, (3) develop effective messages aimed at disease management and prevention, and (4) foster the development of training programs to enhance provider skills for the delivery of patient care. To address these objectives, the investigators and CDC have developed and implemented a web-based patient registry to follow prospectively service allocation and patient outcomes. Funding for the program began in October 2001. All eight funded centers are affiliated with U.S. medical schools. Principal investigators at the centers are hematologists (five adult, two pediatric) or cardiologists. Faculty in obstetrics-gynecology, surgery, and multiple other specialties are integral to the model of care at the centers. Other critical components at the centers are clinical laboratory services, training programs, research networks, and education and outreach programs. From August 2003 to March 2006, over 2,600 patients were enrolled in the registry, accounting for a total of more than 5,000 visits to the centers. Immediate goals of the data collection at the centers are to characterize patients receiving care at centers and document the state of health services provided. Long-term goals are to evaluate prospectively clinical outcomes for patients receiving multidisciplinary care and prevention services at centers. The network of data collection across centers will facilitate future collaborative clinical and epidemiologic investigations and enhance collective expertise in hemostasis and coagulation disorders.

Screening women with menorrhagia for underlying bleeding disorders: the utility of the platelet function analyser and bleeding time

Menorrhagia is a very common clinical problem among women of reproductive age and recent studies have suggested that underlying bleeding disorders, particularly von Willebrand's deficiency and platelet function defects, are prevalent in women presenting with menorrhagia. The objective of this study was to determine the utility of the platelet function analyser (PFA-100) and bleeding time (BT) as initial screening tests for underlying bleeding disorders in women with menorrhagia. In this study, 81 women with a physician diagnosis of menorrhagia underwent PFA-100 testing, BT and comprehensive haemostatic testing. The effectiveness of the PFA-100 and BT as screening tools in women with menorrhagia was assessed using results of haemostatic testing for von Willebrand's disease (VWD) and platelet dysfunction. In women presenting with menorrhagia, the PFA-100 had a sensitivity 80%, specificity 89%, positive predictive value (PPV) 33%, negative predictive value (NPV) 98% and efficiency 88% for VWD. For platelet aggregation defects, the PFA-100 closure time had a sensitivity 23%, specificity 92%, PPV of 75%, NPV of 52% and efficiency 55%. The data suggest that the PFA-100 may be useful in stratifying women with menorrhagia for further von Willebrand testing; however, neither the PFA-100 nor the BT tests are effective for purposes of classifying women for standard platelet aggregometry testing in women presenting with menorrhagia.

Combined venous sinus angioplasty and low-dose thrombolytic therapy for treatment of hemorrhagic transverse sinus thrombosis in a pediatric patient

We describe the successful treatment of a 5-year-old girl with rapidly evolving left hemispheric hemorrhagic infarcts resulting from left transverse and sigmoid sinus thrombosis using combined endovascular dural sinus angioplasty and local low-dose thrombolytic therapy.

Age and the Prevalence of Bleeding Disorders in Women With Menorrhagia

OBJECTIVE

A study was conducted to evaluate the frequency and types of hemostatic defects occurring in adolescent and perimenopausal-age women diagnosed with menorrhagia.

METHODS

A total of 115 women with a physician diagnosis of menorrhagia, including 25 adolescent women, 25 perimenopausal-age women, and 65 women between the ages of 20 and 44, underwent comprehensive hemostatic testing for possible bleeding disorders. Frequencies of bleeding disorders were calculated and compared.

RESULTS

Forty-seven percent of women were found to have hemostatic abnormalities, including platelet dysfunction, von Willebrand's disease, and coagulation factor deficiencies. Adolescents and perimenopausal-age women with menorrhagia were just as likely to have hemostatic abnormalities as were women aged 20 to 44.

CONCLUSION

These results demonstrate that underlying bleeding disorders are frequently found in adolescent, postadolescent reproductive age, and perimenopausal-age women presenting with menorrhagia and suggest that women with menorrhagia should be considered for further hemostatic evaluation.

Low molecular weight heparin in the treatment of venous and arterial thromboses in the premature infant

OBJECTIVE

Thrombosis in the preterm newborn is a growing problem, a result of improved survival of the smallest and sickest infants. Treatment with low molecular weight heparin (LMWH) has potential advantages, including predictable pharmacokinetics, subcutaneous administration, and minimal monitoring. However, studies with LMWH in term infants demonstrate the need for higher doses as compared with older children and adults. Physiologic differences suggest the need for gestational age-appropriate treatment strategies. Because of the relatively small numbers of infants affected each year, large-scale prospective studies have not been feasible. With the goal of establishing treatment guidelines within our own institution, we reviewed retrospectively our experience with LMWH for the treatment of thrombosis in the preterm infant.

METHODS

Medical and pharmacy records of the intensive care nursery were used to identify preterm infants with venous and arterial thrombosis. Chart documentation, orders, pharmacy records, and radiologic studies were used to develop a retrospective database to assess efficacy and safety of the treatment. Main outcome measures were the dose of LMWH required for therapeutic levels, anti-factor Xa levels achieved, bleeding complications, resolution of thrombosis, additional thromboembolic events, and death from all causes.

RESULTS

Ten preterm infants (mean gestational age: 26 weeks) who were treated with LMWH were identified. Mean patient weight at diagnosis of thrombosis was 1215 g (range: 565-1950 g). All 10 patients had either a current or recent history of a central venous or arterial catheter. Mean starting dose of enoxaparin was 1.25 mg/kg per 12 hours (range: 0.8-2 mg/kg). Therapeutic anti-factor Xa levels were achieved in only 5 patients. Mean time to therapeutic range was 33 days (range: 14-63 days). The mean dose of enoxaparin required to achieve therapeutic levels was 2.27 mg/kg per 12 hours (dose range: 2.0-3.5 mg/kg per 12 hours). Clot resolution was observed in all but 2 patients, both of whom died of complications of their thromboembolic events. No bleeding events that necessitated a change in treatment strategy occurred.

CONCLUSIONS

Higher doses of LMWH are required in the preterm infant as compared with the healthy term neonate. Once therapeutic levels are achieved, continued regular monitoring and dose adjustments are required to maintain anticoagulation in therapeutic range.

A prospective comparative study of 2540 infants and children with newly diagnosed idiopathic thrombocytopenic purpura (ITP) from the Intercontinental Childhood ITP Study Group

OBJECTIVE

To analyze prospectively the impact of age at diagnosis in childhood idiopathic thrombocytopenic purpura (ITP).

STUDY DESIGN

International registry from June 1997 to May 2001, with analysis of data from baseline and 6-month-follow-up questionnaires.

RESULTS

Data from 2540 patients were analyzed, including 203 infants (7.6%), 1860 children > or =1 to <10 years of age (69.1%), and 477 children and adolescents between > or =10 and <16 years of age (17.7%). The mean platelet count at diagnosis was similar in all three groups, as was the percentage of patients with initial platelet count <20x10(9)/L. The male/female ratio was highest in infants and decreased with age (P=.009). Immunoglobulin therapy was used more often in infants and corticosteroids in patients > or =10 years of age. Follow-up information at 6 months was available for 1742 children (68.6%). Chronic ITP was seen less frequently in infants (23.1%) than in children >10 years of age (47.3%, P<.0001). Intracranial hemorrhage occurred in 3 of 1742 children during the first 6 months after the diagnosis of ITP.

CONCLUSIONS

Pediatric patients with ITP from infancy to adolescence exhibit heterogeneity in clinical, demographic, and treatment factors.

Serum levels of substance P are elevated in patients with sickle cell disease and increase further during vaso-occlusive crisis

As a mediator of neurogenic inflammation and pain, we hypothesized that levels of the neuropeptide Substance P (SP) would be elevated in patients with sickle cell disease (SCD) with vaso-occlusive pain crisis. SP is a known stimulator of tumor necrosis factor-alpha (TNF-alpha) release and a promoter of interleukin-8 (IL-8), which are reported to be increased in SCD. These cytokines enhance adhesion of leukocytes to endothelium and may play a role in vaso-occlusive events. Serum levels of IL-8, TNFalpha, and SP were studied in three groups of children aged 2 to 18 years: 30 well children with SCD, 21 with SCD in pain crisis, and 20 healthy age-matched controls. Serum levels of SP were elevated in all SCD patients and were highest in patients in pain crisis. The percentage of sera with detectable levels of IL-8 (>5.0 pmol/L) was increased in SCD patients as compared with the control group. IL-8 levels were similar for well SCD patients and those with pain. TNFalpha levels were not significantly different among the three groups. In three children with SCD, SP was measured at baseline and again during pain crisis. In each case, serum levels during pain crisis were higher than they were when the patient was well. We conclude that levels of SP are high in patients with SCD and increase during pain crisis. These results imply that SP plays a prominent role in the pain and inflammation of SCD and may be a measurable laboratory marker of vaso-occlusive crisis. We speculate that neurokinin receptor antagonists may have a therapeutic potential in the treatment of crisis pain.

Screening for hereditary spherocytosis by use of automated erythrocyte indexes

OBJECTIVE

To determine whether the mean corpuscular hemoglobin concentration (MCHC) or other erythrocyte indexes, as determined by automated cell counters, remains a useful screening test for identifying patients with hereditary spherocytosis (HS).

METHODS

Erythrocyte indexes from 112 children with HS who had not undergone splenectomy were compared with those measured in an equal number of healthy, age-matched children. All indexes were derived from measurements obtained by aperture impedance.

RESULTS

Mean corpuscular hemoglobin concentration in the HS group was 35.9 gm/dl, significantly higher than in normal control subjects (34.3 gm/dl; p < 0.001). Mean erythrocyte distribution width also was significantly higher in patients with HS (19.3 vs 12.6; p < 0.001). The MCHC distinguishes individuals with HS, with an area under the receiver operating characteristic curve of 0.86. Although not disease specific, an erythrocyte distribution width > 14 has 85% sensitivity and 97% specificity and an area under the receiver operating characteristic curve of 0.92. An MCHC > 35 gm/dl has a sensitivity of 70% and a specificity of 86%. Combining the MCHC and erythrocyte distribution width increases the area under the receiver operating characteristic curve to 0.97. Specificity is 100% and likelihood ratio is infinite when both the MCHC and erythrocyte distribution width are elevated.

CONCLUSIONS

The automated MCHC is an effective screening test to identify children with HS. An elevated erythrocyte distribution width adds additional specificity and is itself a powerful screening tool. The combination of the two tests is an excellent predictor for the diagnosis of HS.