Outcome measures for adult and pediatric hemophilia patients with inhibitors

Time between inhibitor detection and start of immune tolerance induction: Association with outcome in the BrazIT study

BACKGROUND

Immune tolerance induction (ITI) is the treatment of choice for eradication of anti-factor VIII (FVIII) neutralizing alloantibodies (inhibitors) in people with inherited hemophilia A and high-responding inhibitor (PwHA-HRi). The association between ITI outcome and time elapsed between inhibitor detection and start of ITI (∆tinhi-ITI ) is debatable.

OBJECTIVE

The aim of this study was to evaluate this association among a large cohort of severe PwHA-HRi.

METHODS

Severe (factor VIII activity level <1%) PwHA-HRi on ITI (n = 142) were enrolled in 15 hemophilia treatment centers. PwHA-HRi were treated according to the Brazilian ITI Protocol. ITI outcomes were defined as success (i.e., recovered responsiveness to exogenous FVIII) and failure (i.e., no responsiveness to exogenous FVIII and requirement of bypassing agents to control bleeding).

RESULTS

Median ages at inhibitor detection and at ITI start were 3.2 years (interquartile range [IQR], 1.6-8.1) and 6.9 years [IQR, 2.6-20.1), respectively. PwHA-HRi were stratified according to ∆tinhi-ITI quartiles: first (0.0-0.6 year), second (>0.6-1.7 year), third (>1.7-9.2 years), and fourth quartile (>9.2-24.5 years). The overall success rate was 65.5% (93/142), with no difference among first, second, third, and fourth quartiles (62.9%, 69.4%, 58.3%, and 71.4%, respectively) even after adjusting the analyses for potential confounders.

CONCLUSION

In conclusion, delayed ITI start is not associated with failure of ITI in PwHA-HRi. Therefore, ITI should be offered for these patients, regardless of the time elapsed between the detection of inhibitor and the ITI start.

Practical considerations for nonfactor-replacement therapies in the treatment of haemophilia with inhibitors

New therapeutic agents for haemophilia with inhibitors that are in development or already licensed are expected to provide transformative treatment options. Many of these new therapies are not based on simply replacing the missing factor; new strategies include bispecific antibody technology that mimics factor VIII coagulation function (emicizumab), and inhibition of anticoagulant proteins such as tissue factor pathway inhibitor (eg PF-06741086) and antithrombin (eg fitusiran). These agents are administered subcutaneously and should significantly reduce treatment burden and increase the ability to deliver prophylaxis for patients. Limited real-world data and validated practical guidance on these recently licensed/upcoming treatments resulted in the authors convening to discuss recommendations on their use. Emicizumab is currently the only licenced nonfactor therapy; thus, our recommendations focus on this product. Target candidates for emicizumab prophylaxis are difficult-to-treat patients with haemophilia A and inhibitors and/or venous access issues, frequent bleeds and target joints. In case of breakthrough bleeding while receiving emicizumab, patients still require treatment with bypassing agents; the adjunct treatment of choice is recombinant activated factor VII. This treatment is also recommended to prevent bleeds in patients with inhibitors undergoing surgery. Our recommendations on suitable laboratory assays and monitoring new products, as well as the benefit of patient-reported outcomes (such as pain and physical activity levels), are included. We also briefly discuss future treatment options for patients with haemophilia B and inhibitors. Although these nonfactor treatments offer great promise, further data and real-world evidence are needed.

Expert opinion on the UK standard of care for haemophilia patients with inhibitors: a modified Delphi consensus study

Background and Aims:

Despite advances in haemophilia care, inhibitor development remains a significant complication. Although viable treatment options exist, there is some divergence of opinion in the appropriate standard approach to care and goals of treatment. The aim of this study was to assess consensus on United Kingdom (UK) standard of care for child and adult haemophilia patients with inhibitors.

Methods:

A modified Delphi study was conducted using a two-round online survey. A haemophilia expert steering committee and published literature informed the Round 1 questionnaire. Invited participants included haematologists, haemophilia nurses and physiotherapists who had treated at least one haemophilia patient with inhibitors in the past 5 years. Consensus for 6-point Likert scale questions was pre-defined as ⩾70% participants selecting 1–2 (disagreement) or 5–6 (agreement).

Results:

In all, 46.7% and 35.9% questions achieved consensus in Rounds 1 (n = 41) and 2 (n = 34), respectively. Consensus was reached on the importance of improving quality of life (QoL) and reaching clinical goals such as bleed prevention, eradication of inhibitors and pain management. There was agreement on criteria constituting adequate/inadequate responses to immune tolerance induction (ITI) and the appropriate factor VIII dose to address suboptimal ITI response. Opinions varied on treatment aims for adults and children/adolescents, when to offer prophylaxis with bypassing agents and expectations of prophylaxis. Consensus was also lacking on appropriate treatment for mild/moderate patients with inhibitors.

Conclusion:

UK healthcare professionals appear to be aligned on the clinical goals and role of ITI when managing haemophilia patients with inhibitors, although novel treatment developments may require reassessment of these goals. Lack of consensus on prophylaxis with bypassing agents and management of mild/moderate cases identifies a need for further research to establish more comprehensive, evidence-based treatment guidance, particularly for those patients who are unable/prefer not to receive non-factor therapies.

Is the Detection of Factor IX Inhibitors in Hemophilia B Orphan than Factor VIII Inhibitors in Hemophilia A? A Concise, Systematic Review

OBJECTIVE

Development of inhibitors in hemophilia A and B comprise significant challenge for patients, hematologists, and health provider systems. It has recommended by the World Federation of Hemophilia (WFH) to check inhibitors every 3-4 months. The incidence of inhibitor in hemophilia B is lower than hemophilia A. Here, it tried to unravel whether the detection of inhibitors in hemophilia B neglected compared to hemophilia A or not?

METHODS

A comprehensive review carried out using six international and local medical search engines on published contributions about inhibitors in hemophilia A and B in Iran.

RESULTS

From 699 titles, 12 relevant papers were selected. The mean of factor VIII inhibitors in hemophilia A was 14.8%. The mean of factor IX inhibitors in hemophilia B was 6%. The minimum and maximum reported percentages of factor VIII inhibitors were 4% and 19.6%, while the minimum and maximum of reported percentages of factor IX inhibitors were 0% and 11.8%, respectively. The inhibitors in hemophilia A had reported in 6 papers. One paper had covered the inhibitors in hemophilia B. There were five papers on inhibitors in both hemophilia A and B. The comparison between the reported patients showed that 3020 patients with hemophilia A and 314 patients with hemophilia B had studied.

CONCLUSION

Consistent with the lower frequency of hemophilia B and the lower development of inhibitors in hemophilia B compared to hemophilia A, it was concluded that hemophilia B had not neglected in Iran. It seems to be rational that each country, check rates of detection of inhibitors in hemophilia B to identify whether it has neglected or not.

Cross-Sectional and Longitudinal Construct Validity of the Generic KINDL-A(dult)B(rief) Questionnaire in Adults with Thrombophilia or with Hereditary and Acquired Bleeding Disorders

BACKGROUND/AIMS

The newly adapted generic KINDL-A(dult)B(rief) questionnaire showed satisfactory cross-sectional psychometric properties in adults with bleeding disorders or thrombophilia. This investigation aimed to evaluate its cross-sectional and longitudinal construct validity.

METHODS

After ethical committee approval and written informed consent, 335 patients (mean age 51.8 ± 16.6 years, 60% women) with either predominant thrombophilia (n = 260) or predominant bleeding disorders (n = 75) participated. At baseline, patients answered the KINDL-AB, the MOS 36-item Short-Form Health Survey (SF-36), and the EQ-5D-3L. A subgroup of 117 patients repeated the questionnaire after a median follow-up of 2.6 years (range: 0.4-3.5). A priori hypotheses were evaluated regarding convergent correlations between KINDL-AB overall well-being and specific subscales, EQ-5D-3L index values (EQ-IV), EQ-5D visual analog scale (EQ-VAS), and SF-36 subscales.

RESULTS

Contrary to hypothesis, baseline correlations between the KINDL-AB and EQ-IV/EQ-VAS were all moderate while, as hypothesized, several KINDL-AB subscales and SF-36 subscales correlated strongly. At follow-up, no significant changes in all three instruments occurred. Correlations between instruments over the follow-up were mostly moderate and partially strong. Contrary to hypothesis but consistent with no significant changes in health-related quality of life, convergent correlations between changes in KINDL-AB overall well-being, physical and psychological well-being, and EQ-IV/EQ-VAS were all weak.

CONCLUSIONS

While repeated measures of KINDL-AB showed moderate to strong correlations, changes in KINDL-AB overall well-being and subscales correlated more weakly than expected with changes involving two established instruments of generic health status.

Annual Bleeding Rates: Pitfalls of Clinical Trial Outcomes in Hemophilia Patients

Emerging treatment options for hemophilia, including gene therapy, modified factor products, antibody‐based products, and other nonreplacement therapies, are in development or on their way to marketing authorization. For proof of efficacy, annual bleeding rates (ABRs) have become an increasingly important endpoint in hemophilia trials. We hypothesized that ABR analyses differ substantially between and within medicinal product classes and that the ABR observation period constitutes a major bias. For ABR characterization, an internal factor VIII (FVIII) treatment database has been built based on confidential clinical trial data submitted to the Paul‐Ehrlich‐Institut (PEI). Furthermore, anonymized data from 46 trial protocols submitted for review to the PEI were analyzed (FVIII replacement, n = 27; antibody‐based, n = 12; and gene therapy, n = 7) for methodology. Definitions of bleeding episodes and ABR observational periods differed substantially in clinical trials. In the initial observation phase, individual ABRs of patients, treated prophylactically for 1 year, vary by about 40% (P < 0.001), which finally led to a significant reduction of the ABR group mean by 20% (P < 0.05). Furthermore, the high variance in ABRs constitutes a major challenge in statistical analyses. In conclusion, considerable heterogeneity and bias in the ABR estimation in clinical trials was identified, which makes it substantially more difficult to compare the efficacy of different treatment regimens and products. Thus, awareness of the important pitfalls when using ABR as a clinical outcome is needed in the evaluation of hemophilia therapies for patients, physicians, regulators, and health technology assessment agencies.