The Jamaican Haemophilia Registry: Describing the burden of disease

Haemophilia item bank based on International Classification of Functioning, Disability and Health: a systematic review

BACKGROUND AND OBJECTIVES

Haemophilia comprises a continuum of blood disorders that often include joint and muscular dysfunction, which may lead to a constellation of activity limitations and participation restrictions. However, there is scant research incorporating functional assessment scales into the common language provided by the International Classification of Functioning, Disability and Health (ICF). This study aims to identify the ICF categories to include in an item bank of functioning aspects relevant for haemophilia.

DESIGN AND METHODS

A systematic search was carried out in July 2021 based on the PubMed MEDLINE, CLINICAL, and Cochrane databases for qualified articles, investigating haemophilia-specific scales and the scales recommended by the World Federation of Haemophilia (WFH) linked to ICF categories between 2001 and 2021. Well-trained healthcare professionals in the haemophilia field and ICF evaluation conducted group discussions to determine the ICF items for haemophilia.

RESULTS

A total of 112 out of 176 items measuring function were collected for the haemophilia ICF item bank, including 32 items for body function (b), 45 items for activity and participation (d), 27 items for environmental factors (e), and 8 items for body structure(s).

INTERPRETATION AND CONCLUSIONS

We recommend that future haemophilia research use the haemophilia-specific ICF item bank, which could capture a whole spectrum of functional measurements and facilitate multidisciplinary and worldwide communication. This study also indicates that further development and analysis of the psychometric properties of the 112 haemophilia-related ICF items is warranted.

Psychometric Validation of the Haemo-QOL-A in Participants with Hemophilia A Treated with Gene Therapy

Purpose

The hemophilia-specific health-related quality of life (HRQOL) questionnaire (Haemo-QOL-A) is validated for detecting QOL changes following standard therapy for hemophilia A, but has not been rigorously evaluated after gene therapy. This post hoc analysis evaluated the psychometric properties of Haemo-QOL-A in adult people with severe hemophilia A (PWSHA) receiving valoctocogene roxaparvovec (AAV5-hFVIII-SQ) in 2 clinical trials (phase 1/2, NCT02576795; phase 3, NCT03370913).

Patients and Methods

Adult PWSHA (factor VIII levels ≤1 IU/dL) received 1 AAV5-hFVIII-SQ infusion (6×10¹³ vg/kg). Participants were assessed using the Haemo-QOL-A and the EuroQOL (EQ)-5D-5L and visual analog scale (VAS) questionnaires pre- and post-infusion. Psychometric analyses included convergent and discriminant validity, internal consistency, and reliability. Clinically important difference (CID) was estimated using 3-point change in EQ-5D-5L VAS as anchor.

Results

Haemo-QOL-A data were analyzed from 7 (phase 1/2, 3-year follow-up) and 16 participants (phase 3, 26-week analysis). Change in Haemo-QOL-A Total Scores correlated with EQ-5D-5L VAS score change at 26 weeks (Pearson’s correlation 0.77). At 26 weeks, increased Haemo-QOL-A Physical Functioning was associated with decreased EQ-5D-5L Pain and Discomfort and decreased Anxiety and Depression (Spearman’s Rank correlations −0.73 and −0.62, respectively, P <0.01). Internal consistency analysis showed good reliability for all domains (Cronbach’s alpha >0.7) except Treatment Concern (Cronbach’s alpha = 0.31). Anchor-based CID estimates were met for Haemo-QOL-A Total Score (≥5.5) and domain scores (≥6) for Consequences of Bleeding, Physical Functioning, Role Functioning, and Worry.

Conclusion

Our preliminary results suggest that the Haemo‐QOL‐A is a valid, reliable instrument for HRQOL assessment in PWSHA undergoing gene therapy. Future research should be undertaken to confirm these findings in a larger number of participants.

Persistence of haemostatic response following gene therapy with valoctocogene roxaparvovec in severe haemophilia A

Introduction

Valoctocogene roxaparvovec is an investigational AAV5‐based factor VIII (FVIII) gene therapy that has demonstrated sustained clinical benefit in people with severe haemophilia A.

Aim

To report safety, tolerability, efficacy, and quality of life (QOL) among participants who received valoctocogene roxaparvovec in a phase 1/2 clinical study (NCT02576795).

Methods

Men ≥18 years of age with severe haemophilia A (FVIII ≤1 IU/dl) without history of FVIII inhibitors or anti‐AAV5 antibodies received a single infusion of valoctocogene roxaparvovec and were followed for 5 years (6 × 10¹³ vg/kg dose, n = 7) and 4 years (4 × 10¹³ vg/kg dose, n = 6).

Results

Over the past 2 years, few adverse events and no FVIII inhibitors were reported. Per chromogenic substrate (CSA) assay at years 5 and 4, four of seven and three of six participants in the 6 × 10¹³ and 4 × 10¹³ vg/kg cohorts, respectively, maintained median FVIII levels >5 IU/dl, corresponding to mild haemophilia. By regression analysis, rate of change in FVIII activity was ‐0.14 (95% confidence interval [CI]: ‐.32 to .03) IU/dl/wk in the 6 × 10¹³ vg/kg cohort in year 5 and ‐.06 (95% CI: ‐.14 to .01) IU/dl/wk in the 4 × 10¹³ vg/kg cohort in year 4. No participants resumed FVIII prophylaxis, and eight of 13 participants reported zero bleeds in the past 2 years. Improved QOL from baseline persisted in the 6 × 10¹³ vg/kg cohort; all six Haemo‐QOL‐A domain scores increased. For the 4 × 10¹³ vg/kg cohort, high baseline Haemo‐QOL‐A scores persisted.

Conclusion

These results demonstrate transgene expression and haemostatic response for up to 5 years in individuals with haemophilia A.

Patient-relevant health outcomes for hemophilia care: Development of an international standard outcomes set

BACKGROUND

Patient-relevant health outcomes for persons with hemophilia should be identified and prioritized to optimize and individualize care for persons with hemophilia. Therefore, an international group of persons with hemophilia and multidisciplinary health care providers set out to identify a globally applicable standard set of health outcomes relevant to all individuals with hemophilia.

METHODS

A systematic literature search was performed to identify possible health outcomes and risk adjustment variables. Persons with hemophilia and multidisciplinary health care providers were involved in an iterative nominal consensus process to select the most important health outcomes and risk adjustment variables for persons with hemophilia. Recommendations were made for outcome measurement instruments.

RESULTS

Persons with hemophilia were defined as all men and women with an X-linked inherited bleeding disorder caused by a deficiency of coagulation factor VIII or IX with plasma activity levels <40 IU/dL. We recommend collecting the following 10 health outcomes at least annually, if applicable: (i) cure, (ii) impact of disease on life expectancy, (iii) ability to engage in normal daily activities, (iv) severe bleeding episodes, (v) number of days lost from school or work, (vi) chronic pain, (vii) disease and treatment complications, (viii) sustainability of physical functioning, (ix) social functioning, and (x) mental health. Validated clinical as well as patient-reported outcome measurement instruments were endorsed. Demographic factors, baseline clinical factors, and treatment factors were identified as risk-adjustment variables.

CONCLUSION

A consensus-based international set of health outcomes relevant to all persons with hemophilia, and corresponding measurement instruments, was identified for use in clinical care to facilitate harmonized longitudinal monitoring and comparison of outcomes.

Outcome measures in Haemophilia: Beyond ABR (Annualized Bleeding Rate)

Options for management of haemophilia are increasing rapidly with completely novel therapeutic approaches that cannot be compared using traditional factor assays. In addition, as prophylaxis regimens have improved, bleeding rates have decreased, and consequently, it is difficult to show an impact of novel therapies on rates of spontaneous bleeding. There is currently an urgent need for a panel of outcome measures to compare therapies that are dissimilar in many essential ways. Conventional objective outcome measures including joint physical examination and joint imaging continue to hold a central importance. Factor assays are essential for evaluation of products derived from native factor genes, but are not applicable to some extended half-life factors or non-factor bypassing agents. Global assays including thrombin generation and chromogenic assays of factor X activation are under investigation for their usefulness in haemophilia assessment. Bleeding rate is a conventional subjective patient-reported outcome that, while decreasing in frequency, is indispensable as an outcome given that the primary manifestation of haemophilia is bleeding. Other patient-reported outcomes such as pain intensity and interference, health-related quality of life and activities and participation are increasingly important to distinguish superior outcomes in comparative trials. This review of outcome measures for haemophilia presents examples of existing outcome measures with an emphasis on their strengths and limitations.

Impact of prophylaxis on health-related quality of life of boys with hemophilia: An analysis of pooled data from 9 countries

BACKGROUND

Prophylaxis reduces the frequency of bleeds in boys with severe hemophilia and is the standard care for their management in resource-abundant countries. The effect of prophylaxis on Health-Related Quality of Life (HRQoL) has not been established, because the sample sizes of most studies are too small to explore the relationship of multiple factors that influence HRQoL.

METHODS

The aim of this study was to assess the impact of hemophilia severity and treatment regimen on HRQoL and to establish the minimum important difference (MID) using the international level of score distributions. HRQoL data were pooled from 7 studies across 9 countries. HRQoL was measured using the Canadian Hemophilia Outcomes-Kids' Life Assessment Tool (CHO-KLAT). A mixed-effect linear regression analysis was employed to assess the impact of prophylaxis on the CHO-KLAT score.

RESULTS

Data from 401 boys with hemophilia were analyzed (57.6% severe hemophilia and 57.6% receiving prophylaxis). The model revealed that receiving prophylaxis was significantly associated with higher HRQoL (regression coefficient 8.5, 95% confidence interval [CI] 3.9-13.1). Boys with severe hemophilia had a significantly lower HRQoL as compared to boys with moderate and mild hemophilia whose CHO-KLAT scores were 7.0 and 6.6 points higher, respectively. There was a significant interaction between treatment and disease severity (P = 0.023), indicating prophylaxis has the most significant impact in boys with severe hemophilia. Based on these pooled data, the MID of the CHO-KLAT was established at 6.5.

CONCLUSIONS

This study confirms the positive effect of prophylaxis on HRQoL in boys with hemophilia in a real-world setting and provides initial benchmarks for interpreting HRQoL scores based on use of the CHO-KLAT instrument.