Anti-drug antibodies against the PEG moiety inhibit the procoagulant activity of therapeutic PEGylated FVIII

BACKGROUND

The standard therapy for hemophilia A (HA) patients is the replacement with Factor VIII (FVIII) therapeutics. To overcome the limitation of the short half-life of wild-type FVIII protein, polyethylene glycol (PEG) can be coupled to therapeutic FVIII to improve pharmacokinetics.

OBJECTIVES

To characterize antibodies developed against a FVIII therapeutic PEGylated with a 40 kDa PEG (40PEG-BDD_FVIII) in two mild HA patients.

METHODS

An in-house bead-based immunoassay was developed to characterize and confirm the specificity of detected antibodies. The neutralizing nature of the antibodies towards PEGylated therapeutics was determined by a modified Nijmegen Bethesda Assay (NBA).

RESULTS

Two out of 46 patients treated with 40PEG-BDD_FVIII developed inhibitory antibodies towards the drug. Switching to a non-PEGylated FVIII successfully increased the FVIII activity in both patients. In Patient 1, antibodies were raised against FVIII and PEG. Anti-FVIII antibodies were of IgG isotype, whereas anti-PEG antibodies were of IgG, IgM, and IgA isotype. In Patient 2, antibodies of IgG and IgA isotype were directed only against the PEG moiety. Competitive assays confirmed the specificity of the antibodies against PEG. The applied NBA revealed that patients anti-PEG antibodies and AGP3, an antibody against the backbone of PEG, can inhibit all currently available PEGylated therapeutics but to different degrees. No inhibitory FVIII antibodies were detected.

CONCLUSION

Antibodies against the PEG moiety of 40PEG-BDD_FVIII abolished the efficacy of the drug. This is the first report on real-world experiences with the development of neutralizing anti-PEG antibodies after treatment with PEGylated FVIII therapeutic in mild HA.

The value of radiosynoviorthesis for treatment of chronic synovitis in hemophilic joint disease

Chronic synovitis is contributing to the development of arthropathy in hemophilia A and B. In most patients with severe and moderate hemophilia, during lifetime, joint damage progresses despite early prophylaxis and intense treatment with coagulation factor concentrates. Recurrent hemorrhages into the joints and subclinical bleeding lead to chronic inflammation of the synovium, neoangiogenesis and remodeling, sustaining a vicious circle of bleeding-remodeling-bleeding and progression of osteochondral damage. Imaging techniques including ultrasound and MRI are able to early visualize synovitis and osteochondral changes. Early detection and sustained therapy of synovitis are important preconditions to prevent further deterioration of joint status. Chronic synovitis requires intensified substitution of coagulation factors and concomitant analgetic, antiphlogistic and physical therapy. The value of early radiosynoviorthesis (RSO) as effective method to control ongoing synovitis is discussed here. RSO is recommended as first choice therapy in case of persistant chronic synovitis, recorded in both national and international guidelines.

Safety of intramuscular COVID-19 vaccination in patients with haemophilia

Background

Guidelines recommend that patients with haemophilia should preferably receive vaccination subcutaneously. COVID‐19 and other vaccines, however, are only licenced for intramuscular application.

Aims

To assess the safety of intramuscular COVID‐19 vaccination in patients living with haemophilia.

Methods

Part A of this prospective observational study enrolled consecutive patients with haemophilia A (HA) and B (HB) of all ages and severities and assessed injection site bleeding and other complications within 30 days of vaccination. Part B enrolled patients providing informed consent for detailed data collection including medication and prophylaxis around the time of vaccination. Logistic regression was performed to assess potential risk factors for bleeding.

Results

Four hundred and sixty‐one patients were enrolled into part A. The primary endpoint injection site bleeding occurred in seven patients (1.5%, 95% confidence interval .7–3.1%). Comprehensive analysis of 214 patients (404 vaccinations, part B) revealed that 97% of patients with severe haemophilia had prophylaxis before vaccination, either as part of their routine prophylaxis or using additional doses. 56% and 30% of patients with moderate and mild haemophilia, respectively, received prophylaxis before vaccination. Among the seven bleeds recorded, three occurred when intramuscular vaccination was done without prophylaxis (odds ratio 12).

Conclusions

This is the first prospective study reporting on the safety of intramuscular vaccination in haemophilia. The rate of injection site bleeding was low in mild haemophilia, and in moderate and severe haemophilia if patients received factor prophylaxis.

Consensus Recommendations for Intramuscular COVID-19 Vaccination in Patients with Hemophilia

BACKGROUND

 Currently available coronavirus disease 2019 (COVID-19) vaccines are approved for intramuscular injection and efficacy may not be ensured when given subcutaneously. For years, subcutaneous vaccination was recommended in patients with hemophilia to avoid intramuscular bleeds. Therefore, recommendations for the application of COVID-19 vaccines are needed.

METHODS

 The Delphi methodology was used to develop consensus recommendations. An initial list of recommendations was prepared by a steering committee and evaluated by 39 hemophilia experts. Consensus was defined as ≥75% agreement and strong consensus as ≥95% agreement, and agreement as a score ≥7 on a scale of 1 to 9. After four rounds, a final list of statements was compiled.

RECOMMENDATIONS

 Consensus was achieved that COVID-19 vaccines licensed only for intramuscular injection should be administered intramuscularly in hemophilia patients. Prophylactic factor replacement, given on the day of vaccination with a maximum interval between prophylaxis and vaccination of 24 hours (factor VIII and conventional factor IX concentrates) or 48 hours (half-life extended factor IX), should be provided in patients with moderate or severe hemophilia. Strong consensus was achieved that patients with mild hemophilia and residual factor activity greater than 10% with mild bleeding phenotype or patients on emicizumab usually do not need factor replacement before vaccination. Swelling, erythema, and hyperthermia after vaccination are not always signs of bleeding but should prompt consultation of a hemophilia care center. In case of injection-site hematoma, patients should receive replacement therapy until symptoms disappear.

CONCLUSIONS

 Consensus was achieved on recommendations for intramuscular COVID-19 vaccination after replacement therapy for hemophilia patients depending on disease severity.

Prevalence of Obesity in Young Patients with Severe Haemophilia and Its Potential Impact on Factor VIII Consumption in Germany

Similar to the general population, overweight and obesity have increasingly become a medical and economic burden also in patients with haemophilia in industrialized nations. In this study in seven German haemophilia centres, we identified a prevalence of overweight and obesity of 25.2% among 254 young patients <30 years (median: 13 years; range: 0–30 years) with severe haemophilia A and without a history of inhibitors. The median FVIII dosage based on bodyweight was significantly higher in normal weight compared with overweight or obese patients (96.9 vs. 72.9 IU/kg/week, respectively; p < 0.0001). This suggests that an individualized dosing regime which might be based on FVIII pharmacokinetics, physical activity and pre-existing haemophilic arthropathy is applied rather than dosing by bodyweight only. The bleeding rates observed in obese (median: 1; range: 0–17) versus normal weight patients (median: 2; range: 0–28) did not differ significantly (p = 0.057). Lower bleeding rates might be due to reduced activity or expected higher FVIII plasma levels in overweight patients. Due to the increasing prevalence of overweight/obesity in patients with haemophilia an interdisciplinary approach for individualized haemophilia treatment and weight loss programmes might be helpful for optimal and economical treatment for this group of patients.

Impact of Telemedicine Tools on Record Keeping and Compliance in Haemophilia Care

Background Record keeping is integral to home treatment for haemophilia. Issues with paper diaries include questionable compliance, data validity and quality. Implementation of electronic diaries (e-diaries) in haemophilia patients could improve documentation of home treatment.

Aim This article evaluates the effects of an e-diary, Haemoassist, on recording and patient compliance with therapy.

Patients and Methods An explorative study was used to assess the sequential use of paper diaries and e-diaries by 99 patients with severe haemophilia A or B and 1 with severe factor VII deficiency. Median age was 41 years. Information was obtained from paper records for 3 years preceding the introduction of an electronic record system and the first 6 to 12 months of Haemoassist use. Data from the 3-year period were averaged. Missing data for rounded 12 months of e-diary use were extrapolated to correspond to a full year.

Results Enhancement of 23% in record delivery was observed for the period of Haemoassist use (p = 0.013). Twenty-one percent increase in patients’ compliance for data reporting (from 65% 35 to 86% 22, p = 0.003) and 16% increase for documentation of bleedings (from 68 to 84% of patients, p = 0.01) were detected. Compliance to prescribed therapy of patients for the whole studied period improved by 6% (from 82% ± 29 to 88% ± 25, p = 0.05). Major advances were demonstrated predominantly in the age groups of between 13 and 20 and 21 and 40 years.

Conclusion e-Diaries' use enables improved recording of information about patients' home treatment and bleeding episodes. Enhanced compliance with therapy may be a further benefit.

Combined coagulation factor VIII and factor IX deficiency (CDF8F9) in a patient from Lithuania

Haemophilia A (FVIII deficiency) and haemophilia B (FIX deficiency) are X-linked inherited bleeding disorders. It is a very rare event to identify both haemophilias in the same patient. So far, only two families with such combination are reported in the literature worldwide supported by genetic background. Patients and methods: Evaluation of clinical data, determination of FVIII and FIX levels and genetic analysis of F8 and F9 genes by direct sequencing. Results: We report on a patient having severe haemophilia B (FIX:C <1 IU dl-1) and mild haemophilia A (FVIII:C 18 IU dl-1 ). FIX deficiency was known since childhood, whereas mild haemophilia A was confirmed at the age of 42 due to unexpected bleeding complications after dental extraction despite adequate substitution with plasma derived FIX concentrate. F9 gene analysis showed a point mutation in exon 2 (c.223C>T, p.R75X), whereas F8 gene analysis revealed a point mutation in exon 4 (c.545A>C, p.D182A). The mother of the patient was heterozygous for F8 mutation, but not for F9 mutation suggesting a de novo F9 mutation. Accidentally, further family from Germany with mild Haemophilia A was identified to have the same F8 mutation. F8 Haplo-type analysis revealed that the p.D182A mutation most likely represents a founder mutation with common ancestors of the German and the Lithuanian family. Conclusions: Our results confirm the rare event of Haemophilia A and haemophilia B in the same patient originating from two distinct genetic defects in F8 and F9 genes.

A novel fibrinogen γ chain frameshift deletion (c.637delT) in a patient with hypodysfibrinogenemia associated with thrombosis

Inherited fibrinogen (FG) disorders are rare and result in quantitative or/and qualitative FG deficiency. While the majority of patients with clinically relevant FG deficiencies demonstrate a bleeding phenotype, a subset of patients are at increased risk of thrombosis.

We report a 54-years old man presenting with a thrombophilic phenotype characterized by two episodes of unprovoked venous thrombosis and a deep vein thrombosis several weeks after myocardial infarction. Recently, he developed A. carotis communis thrombosis and died. Coagulation tests were done using standard procedures. FG genes were screened using direct sequencing. Effect on fibrin clot structure was analyzed by scanning electron microscopy (SEM) and FG chain polymerization was analysed using SDS-PAGE.

While thrombophilia testing was negative, we found a decreased concentration of clottable FG (126-148 mg/dl) compared to FG antigen (182-194 mg/dl of normal). The thrombin time was slightly prolonged, while aPTT and reptilase time were within the normal range. A novel deletion in FGG gene (c.637delT) resulting in a frameshift and the premature termination of the γ chain at amino acid position p.228 was identified. SDS-PAGE showed a time-shift in γ-γ and α-α cross linking. SEM showed no statistically significant differences between the patient´s and a healthy control´s fibrin clot structure.

In addition to the reduction of FG concentration expected by the nature of the mutation also a functional defect (hypodysfibrinogenemia) was found. Moreover this mutation seems to increase the risk of thrombosis warranting long term anticoagulation possibly in a combination with antiplatelet drugs.

Haemophilia and thrombophilia

For the study presented here 135 pediatric PUP patients with haemophilia consecutively admitted to German pediatric haemophilia treatment centers were investigated. In addition to factor VIII activity, the factor V (FV) G1691A mutation, the factor II (FII) G20210A variant, methylenetetrahydrofolate reductase (MTHFR) T677T genotype, elevated lipoprotein a (Lp a), antithrombin, protein C, and protein S were investigated. 103 out of 122 HA patients (FVIII activity <1%) were suffering from severe HA. The prevalence of prothrombotic risk factors in children with severe haemophilia A (HA) did not differ from previously reported data: FV GA 5.8%, FII GA 3.9%, MTHFR TT 10%, elevated Lp a 7%, protein C type I deficiency 1.1%. The first symptomatic bleeding leading to diagnosis of severe haemophilia occurred with a median age of 1.6 years (range: 0.5-7.1 years) in children carrying prothrombotic risk factors compared to non-carriers (0.9 years (0.1-4.0; p = 0.01). Two patients presenting with neonatal stroke due to elevated Lp a and the FII GA variant showed haemorrhagic stroke transformation triggered by severe haemophilia. In addition, when haemophilia A was corrected by administration of factor VIII concentrates eight out of 25 children with central lines in place developed catheter-related thrombosis. Conclusion: The data of this multicentre cohort study demonstrate that the clinical phenotype of severe haemophilia A in childhood is clearly influenced by the coinheritance of prothrombotic risk factors.

Combined coagulation factor VIII and factor IX deficiency (CDF8F9) in a patient from Lithuania

Haemophilia A (FVIII deficiency) and haemophilia B (FIX deficiency) are X-linked inherited bleeding disorders. It is a very rare event to identify both haemophilias in the same patient. So far, only two families with such combination are reported in the literature worldwide supported by genetic background.

PATIENTS AND METHODS

Evaluation of clinical data, determination of FVIII and FIX levels and genetic analysis of F8 and F9 genes by direct sequencing.

RESULTS

We report on a patient having severe haemophilia B (FIX:C <1 IU dl^-1) and mild haemophilia A (FVIII:C 18 IU dl^-1 ). FIX deficiency was known since childhood, whereas mild haemophilia A was confirmed at the age of 42 due to unexpected bleeding complications after dental extraction despite adequate substitution with plasma derived FIX concentrate. F9 gene analysis showed a point mutation in exon 2 (c.223C>T, p.R75X), whereas F8 gene analysis revealed a point mutation in exon 4 (c.545A>C, p.D182A). The mother of the patient was heterozygous for F8 mutation, but not for F9 mutation suggesting a de novo F9 mutation. Accidentally, further family from Germany with mild Haemophilia A was identified to have the same F8 mutation. F8 Haplotype analysis revealed that the p.D182A mutation most likely represents a founder mutation with common ancestors of the German and the Lithuanian family.

CONCLUSIONS

Our results confirm the rare event of Haemophilia A and haemophilia B in the same patient originating from two distinct genetic defects in F8 and F9 genes.

A novel fibrinogen γ chain frameshift deletion (c.637delT) in a patient with hypodysfibrinogenemia associated with thrombosis

Inherited fibrinogen (FG) disorders are rare and result in quantitative or/and qualitative FG deficiency. While the majority of patients with clinically relevant FG deficiencies demonstrate a bleeding phenotype, a subset of patients are at increased risk of thrombosis.

PATIENTS AND METHODS

We report a 54-years old man presenting with a thrombophilic phenotype characterized by two episodes of unprovoked venous thrombosis and a deep vein thrombosis several weeks after myocardial infarction. Recently, he developed A. carotis communis thrombosis and died. Coagulation tests were done using standard procedures. FG genes were screened using direct sequencing. Effect on fibrin clot structure was analyzed by scanning electron microscopy (SEM) and FG chain polymerization was analysed using SDS-PAGE.

RESULTS

While thrombophilia testing was negative, we found a decreased concentration of clottable FG (126-148 mg/dl) compared to FG antigen (182-194 mg/dl of normal). The thrombin time was slightly prolonged, while aPTT and reptilase time were within the normal range. A novel deletion in FGG gene (c.637delT) resulting in a frameshift and the premature termination of the γ chain at amino acid position p.228 was identified. SDS-PAGE showed a time-shift in γ-γ and α-α cross linking. SEM showed no statistically significant differences between the patient´s and a healthy control´s fibrin clot structure.

CONCLUSIONS

In addition to the reduction of FG concentration expected by the nature of the mutation also a functional defect (hypodysfibrinogenemia) was found. Moreover this mutation seems to increase the risk of thrombosis warranting long term anticoagulation possibly in a combination with antiplatelet drugs.

Neoplasm-induced bleeding in inherited, heterozygous FXIII-A deficiency

Inherited mild factor XIII deficiency belongs to one of the most underdiagnosed bleeding disorders so far. This is, because most patients do not develop bleeding complications in daily life.

A man (age: 64 years) without a history of bleeding presented with painful swelling of neck, weight loss, anemia and episodic bleeding from the right tonsil necessitating tonsillectomy. Histologic and immunohistochemical evaluation revealed cytokeratinpositive epitheloid angiosarcoma. Blood coagulation status showed significantly elevated D-dimer and decreased FXIII levels (FXIII-activity 35%, FXIIIA-Ag 16–26%). Plasma mixing studies excluded neutralizing antibodies against FXIII.

A novel heterozygous F13A1 gene nonsense mutation (p.Glu103Ter, c.307G>T) was found confirming heterozygous FXIII-A deficiency. The same mutation was detected in two further asymptomatic relatives. For further clinical management the patient was transfused with FXIII-concentrate and showed an adequate increase of FXIII ruling out FXIII deficiency to be induced by increased turnover. Despite this haemostatic management and antifibrinolytic treatment the patient had to undergo several revisions due to delayed, Hb relevant bleeding after cervical lymph nodes extirpation and resection of tonsil. Two chemotherapy cycles with paclitaxel and palliative radiotherapy of the neck area were performed, but the patient died unfortunately two months after diagnosis.

It is a unique case showing the combination of a highly aggressive angiosarcoma and presence of inherited FXIII deficiency. It is also a rare example demonstrating the benefit of FXIII genotyping besides the expected acquired FXIII deficiency possibly due to neoplasm induced increased consumption by elevated crosslinking of fibrin fibers.

Neoplasm-induced bleeding in inherited, heterozygous FXIII-A deficiency

Inherited mild factor XIII deficiency belongs to one of the most underdiagnosed bleeding disorders so far. This is, because most patients do not develop bleeding complications in daily life. Patient, methods: A man (age: 64 years) without a history of bleeding presented with painful swelling of neck, weight loss, anemia and episodic bleeding from the right tonsil necessitating tonsillectomy. Histologic and immunohistochemical evaluation revealed cytokeratin-positive epitheloid angiosarcoma. Blood coagulation status showed significantly elevated D-dimer and decreased FXIII levels (FXIII-activity 35%, FXIIIA-Ag 16-26%). Plasma mixing studies excluded neutralizing antibodies against FXIII.

RESULTS

A novel heterozygous F13A1 gene nonsense mutation (p.Glu103Ter, c.307G>T) was found confirming heterozygous FXIII-A deficiency. The same mutation was detected in two further asymptomatic relatives. For further clinical management the patient was transfused with FXIII-concentrate and showed an adequate increase of FXIII ruling out FXIII deficiency to be induced by increased turnover. Despite this haemostatic management and antifibrinolytic treatment the patient had to undergo several revisions due to delayed, Hb relevant bleeding after cervical lymph nodes extirpation and resection of tonsil. Two chemotherapy cycles with paclitaxel and palliative radiotherapy of the neck area were performed, but the patient died unfortunately two months after diagnosis.

CONCLUSIONS

It is a unique case showing the combination of a highly aggressive angiosarcoma and presence of inherited FXIII deficiency. It is also a rare example demonstrating the benefit of FXIII genotyping besides the expected acquired FXIII deficiency possibly due to neoplasm induced increased consumption by elevated crosslinking of fibrin fibers.

Inhibitor development and management in three non-severe haemophilia A patients with T295A variant

Missense mutations are the most common F8 gene defects among the patients with non-severe haemophilia A. This type of mutation is typically associated with low (5%) inhibitor risk. In the present retrospective study we analysed the clinical data of 16 haemophiliacs with the T295A missense mutation treated at Bonn Haemophilia Centre. In total, three patients developed inhibitors: two patients experienced low-titer and one high-titer inhibitors. Both patients with low titer inhibitors underwent successful ITI. The third patient, at the age of 81, developed initially low-titer inhibitors (3 BU/ml) after rFVIII therapy because of knee surgery. He experienced spontaneous multiple large skin haematomas and haemarthrosis. Immunosuppressive therapy was not applicable because of the infectious origin of discitis (Th3-Th4). Immunoadsorption was performed, but the inhibitor titer increased up to 42 BU/ml nine weeks after termination. A successful treatment of discitis with antibiotics finally allowed a weekly therapy (four times) with rituximab (375 mg/m(2)). This resulted in a decrease of inhibitor titre to 0.7 BU/ml eight weeks after the fourth rituximab application. Patient had endogenous FVIII levels of 3-5%. Twelve months after rituximab therapy (after B cells recovery) he relapsed with low-titer inhibitors and therefore was treated with single rituximab dose (375 mg/m(2)) again. This resulted in his depletion of B cells, measurable endogenous FVIII levels and non measurable inhibitors. This study demonstrated T295A variant to be associated with significantly increased (3/16 patients, 17%) inhibitor development.

Long-term outcome of liver transplantation in HCV/HIV coinfected haemophilia patients. A single centre study of 10 patients

The outcome and clinical features during long term follow-up of 10 haemophilia patients (haemophilia A n = 9, haemophilia B n = 1), who underwent successful orthotopic liver transplantation (OLT) due to hepatitis associated liver disease, are summarised.

PATIENTS

Eight patients were HIV/HCV co-infected. Despite severe postoperative complications, which were not bleeding-associated, all patients survived OLT.

RESULTS

Long-term survival was 70% after in mean 8 years follow-up. Twelve years after OLT one patient developed a cyclosporine-induced nephropathy requiring haemodialysis. HIV-HAART was initiated in all patients after OLT, and allowed a successful HCV treatment in 6 patients. Factor VIII production was sufficient in mean 72 h after OLT and remained stable at subnormal to normal FVIII levels of in median 30% (range 14-96%) also during long-term follow-up. Post-OLT spontaneous bleeding events were rare compared to pre-OLT, therefore, the performance status improved in all patients.

DISCUSSION

OLT substitutes the hepatic FVIII but has no effect on the extra-hepatic endothelial FVIII production, suggesting that in case of severe tissue injury enhanced bleeding might occur. Additionally, after OLT there is no acute phase reaction of the FVIII protein. Therefore, our OLT patients received in case of a reduced FVIII activity a peri-interventional prophylactic short-term FVIII substitution in surgical and diagnostic interventions with high bleeding risk.

CONCLUSION

Bleeding and wound healing disturbances were not seen.

Haemophilia and thrombophilia. What do we learn about combined inheritance of both genetic variations?

For the study presented here 135 pediatric PUP patients with haemophilia consecutively admitted to German pediatric haemophilia treatment centers were investigated. In addition to factor VIII activity, the factor V (FV) G1691A mutation, the factor II (FII) G20210A variant, methylenetetrahydrofolate reductase (MTHFR) T677T genotype, elevated lipoprotein a (Lp a), antithrombin, protein C, and protein S were investigated. 103 out of 122 HA patients (FVIII activity <1%) were suffering from severe HA. The prevalence of prothrombotic risk factors in children with severe haemophilia A (HA) did not differ from previously reported data: FV GA 5.8%, FII GA 3.9%, MTHFR TT 10%, elevated Lp a 7%, protein C type I deficiency 1.1%. The first symptomatic bleeding leading to diagnosis of severe haemophilia occurred with a median age of 1.6 years (range: 0.5-7.1 years) in children carrying prothrombotic risk factors compared to non-carriers (0.9 years (0.1-4.0; p = 0.01). Two patients presenting with neonatal stroke due to elevated Lp a and the FII GA variant showed haemorrhagic stroke transformation triggered by severe haemophilia. In addition, when haemophilia A was corrected by administration of factor VIII concentrates eight out of 25 children with central lines in place developed catheter-related thrombosis.

CONCLUSION

The data of this multicentre cohort study demonstrate that the clinical phenotype of severe haemophilia A in childhood is clearly influenced by the coinheritance of prothrombotic risk factors.