Living with a "hemophilia-free mind" - The new ambition of hemophilia care?

Joint health and pain in the changing hemophilia treatment landscape

INTRODUCTION

Hemophilia is an inherited bleeding disorder. Bleeding, and in particular joint hemorrhage results in chronic arthropathy and disability. Acute and chronic pain are frequent and limit activity and participation and result in decreased health-related quality of life. Remarkable progress has been made in the diagnosis and treatment of hemophilia but bleeding continues to prove recalcitrant to currently available treatments and joint disease remains problematic. Physiotherapy and pain management are mainstays of current multidisciplinary integrated care of people with hemophilia (PWH). The focus of this review is on preservation of joint health in the era of new and innovative therapies.

AREAS COVERED

A search of the PubMed Central was conducted on 1 February 2024 using the MeSH Major Topic terms identified as keywords for the manuscript. This review will highlight what is known and unknown about joint bleeding and arthropathy, including insights on pain as a related complication.

EXPERT OPINION

Recent advances in therapeutic interventions aimed at promoting healthy joints in PWH will be discussed, including both the pharmacological treatment landscape and related strategies to promote joint health.

Valoctocogene roxaparvovec gene therapy provides durable haemostatic control for up to 7 years for haemophilia A

INTRODUCTION

Valoctocogene roxaparvovec is an adeno-associated virus vector serotype 5 (AAV5)-mediated gene therapy approved for severe haemophilia A (HA).

AIM

To report the safety and efficacy of valoctocogene roxaparvovec 7 years after dosing in a phase 1/2 clinical study (NCT02576795).

METHODS

Males ≥18 years with severe HA (factor VIII [FVIII] ≤1 international unit [IU]/dL) who were previously receiving exogenous FVIII and had no history of FVIII inhibitors or anti-AAV5 antibodies received valoctocogene roxaparvovec treatment and were followed for 7 (6 × 1013 vg/kg; n = 7) and 6 (4 × 1013 vg/kg; n = 6) years.

RESULTS

In the last year, one participant in each cohort reported treatment-related adverse events (AEs): grade 1 (G1) hepatomegaly (6 × 1013), and G1 splenomegaly and G1 hepatic steatosis (4 × 1013). During all follow-up, mean annualized treated bleeds and exogenous FVIII infusion rates were ≥88% lower than baseline values. At years 7 and 6, mean (median) FVIII activity (chromogenic assay) was 16.2 (10.3) and 6.7 (7.2) IU/dL in the 6 × 1013 (n = 5) and 4 × 1013 (n = 4) cohorts, respectively, corresponding to mild haemophilia. Regression analyses of the last year estimated rate of change in FVIII activity was -0.001 and -0.07 IU/dL/week for the 6 × 1013 and 4 × 1013 cohorts, respectively. Two participants (6 × 1013) resumed prophylaxis in year 7: one after a non-treatment-related G4 serious AE of spontaneous internal carotid artery bleed, and the other to manage bleeds and FVIII activity.

CONCLUSIONS

The safety and efficacy of valoctocogene roxaparvovec remain generally consistent with previous reports, with good haemostatic control for most participants. Two participants returned to prophylaxis.

Ultra-Long factor VIII: a major step forward toward a hemophilia-free mind

A remarkable step forward in the treatment of hemophilia A has recently been achieved with the development of an Ultra-Long modified factor (F)VIII. Leveraging expertise gained with fusion to immunoglobulin Fc fragments, disconnecting FVIII from endogenous von Willebrand factor (via a D'-D3 fragment), and benefiting from the pharmacokinetic prolongation provided by the addition of hydrophilic polypeptides, efanesoctocog alfa opens a new era in the treatment of hemophilia A. The term Ultra-Long FVIII has been proposed to designate it and differentiate it from extended half-life FVIII. The level of FVIII correction within the normal range for several days provided by this molecule should allow an increasing number of patients to free themselves from the physical and psychological constraints of hemophilia A. Certainly, the burden of weekly intravenous infusions persists but is compensated by a correction of hemostasis whose amplitude and duration remain unmatched by other therapeutic options currently available.

Emicizumab is well tolerated and effective in people with congenital hemophilia A regardless of age, severity of disease, or inhibitor status: a scoping review

Background

With the treatment landscape continually evolving, it is vital that the hemophilia community have an overview of all published data for approved therapies, such as emicizumab, to support shared decision making.

Objectives

To bring together the clinical and real-world data for emicizumab use in people with congenital hemophilia A, regardless of age, disease severity, or factor VIII inhibitor status. Key focus areas were safety, efficacy, and quality of life (QoL).

Methods

This scoping review used citation databases (PubMed, Embase, and the Cochrane Library) and manual searches of abstract books. Publications reporting original data for emicizumab in people with hemophilia A, published in English after December 2014, and reporting select endpoints were included. This narrative synthesis focused on zero bleeds, treated annualized bleeding rate (ABR), adverse events, and QoL measures.

Results

Overall, 97 publications were included (cut-off: August 9, 2022). Treated ABR remained low (calculated mean and median treated ABRs ranged between 0.7-1.3 and 0.0-1.4, respectively), and the median percentage of people with zero treated bleeds was 66.7%. The proportion of people experiencing treatment-related adverse events ranged from 0.0% to 60.0%; most were injection-site reactions. Across 37 publications reporting on safety and enrolling >2300 individuals, 11 thrombotic events and 4 thrombotic microangiopathies were reported. Data from well-established tools show QoL benefits with emicizumab.

Conclusion

This scoping review consolidates the global published experience for emicizumab in people with hemophilia A and supports the fact that emicizumab has an acceptable safety profile, is effective and efficacious in bleed prevention, and is associated with improvements in QoL.

The benefits of gene therapy in people with haemophilia

Haemophilia is an inherited bleeding disorder which causes significant morbidity and mortality, especially in the severe form. Prophylaxis with factor replacement has high efficacy in reducing bleeding but is limited by the need for frequent intravenous infusion and fluctuations in haemostasis between doses. Additional prophylaxis therapies are being developed which may overcome some of the current treatment barriers. Gene therapy (GT) is being developed to provide a functional cure such that there is sustained factor expression and minimal to no need for additional haemostatic therapy. There are now two approved gene therapies for haemophilia which may be transformative for many individuals. Benefits of GT should go beyond increasing factor activity and reducing bleeding as persons with haemophilia aim to achieve a 'haemophilia-free mind' and health equity with optimal health and well-being.

Health-related quality of life following valoctocogene roxaparvovec gene therapy for severe hemophilia A in the phase 3 trial GENEr8-1

BACKGROUND

Severe hemophilia A (HA) negatively impacts health-related quality of life (HRQOL).

OBJECTIVES

We aimed to analyze HRQOL in adult men with severe HA without inhibitors after valoctocogene roxaparvovec gene transfer in the phase 3 trial GENEr8-1.

METHODS

Participant-reported outcomes were the hemophilia-specific quality of life questionnaire for adults (Haemo-QOL-A), the EQ-5D-5L instrument, the Hemophilia Activities List (HAL), and the Work Productivity and Activity Impairment Questionnaire: Hemophilia Specific (WPAI+CIQ:HS). Participants completed the questionnaires at baseline and through 104 weeks postinfusion with 6 × 1013 vg/kg of valoctocogene roxaparvovec. Scores were analyzed per participant characteristics and outcomes.

RESULTS

For 132 HIV-negative participants, mean change from baseline in Haemo-QOL-A Total Score met the anchor-based clinically important difference (CID: 5.5) by week 12; the mean (SD) increase was 7.0 (12.6) at week 104. At week 104, improvement in Consequences of Bleeding, Treatment Concern, Worry, and Role Functioning domain scores exceeded the CID (6). EQ-5D-5L Utility Index scores improved above the CID at week 52, but not at week 104. EQ-5D-5L visual analog scale and HAL scores increased from baseline to week 104. Participants reported less activity and work impairment at week 104 than baseline. Participants with problem joints had lower mean baseline Haemo-QOL-A Total and domain scores than those without them, but improved over 104 weeks, except for 11 participants with ≥3 problem joints. Participants with 0 bleeds during the baseline prophylaxis period reported Haemo-QOL-A score improvements above the CID, including in the Consequences of Bleeding domain.

CONCLUSION

Valoctocogene roxaparvovec provided clinically meaningful HRQOL improvement for men with severe HA.

Targeting higher factor VIII levels for prophylaxis in haemophilia A: a narrative review

INTRODUCTION

The standard of care in severe haemophilia A is prophylaxis, which has historically aimed for a factor VIII (FVIII) trough level of ≥1%. However, despite prophylactic treatment, people with haemophilia remain at risk of bleeds that have physical and quality of life implications, and that impact everyday life.

AIM

The aim of this review was to evaluate evidence supporting the relationship between targeting higher FVIII activity levels with prophylaxis and improved outcomes in people with haemophilia A.

METHODS

We conducted a narrative review that defined the unmet needs and treatment goals in people with haemophilia A, evaluated evidence to support targeting higher FVIII activity levels, and highlighted therapies that may support higher and sustained FVIII activity levels and improved outcomes for people with haemophilia A.

RESULTS

Despite recent advances in treatment, unmet needs remain, and people with haemophilia continue to experience joint and functional impairment, acute and chronic pain, and poor mental health. All these negatively impact their health-related quality of life. Evidence suggests that FVIII activity levels of up to 50% may be needed to achieve a near-zero joint bleed rate. However, achieving high FVIII activity levels with current standard and extended half-life (EHL) FVIII replacement therapies is associated with a high treatment burden. Innovative treatment options may provide high sustained FVIII activity levels and improved patient outcomes.

CONCLUSION

Evidence suggests that FVIII activity levels in people with haemophilia A should be sustained at higher levels to improve joint and patient outcomes and enable progression towards health equity.

Gene therapy for hemophilia, a clinical viewpoint

Gene therapy for hemophilia has been investigated for decades but no breakthroughs were made until Nathwani et al. achieved a significant and sustainable factor IX increase in hemophilia B patients in 2011. About eleven years later, in August 2022, the first hemophilia A gene therapy product was approved by the European Commission and hemophilia treatment entered a new era. This review does not focus on the newest advances but rather the practical aspects of gene therapy aiming to provide an overview for physicians who treat hemophiliacs who did not participate in the clinical trials. The current status of gene therapy, focusing particularly on products likely to be clinically available soon, are reviewed and summarized. Currently, possible limitations of gene therapy are pre-existing neutralizing antibodies toward the vector, liver health, age, and inhibitor status. Possible safety concerns include infusion reactions, liver damage, and adverse effects from immune suppressants or steroids. In summary, generally speaking, gene therapy is effective, at least for several years, but the exact effect may be unpredictable and intensive monitoring for several months is needed. It can also be considered safe with careful practice on selected patients. In its current form, gene therapy will not replace all hemophilia treatments. Advances in non-factor therapy will also improve hemophilia care greatly in the future. We envisage that gene therapy may be included in multiple novel therapies for hemophilia and benefit some hemophilia patients while novel non-factor therapies may benefit others, together fulfilling the unmet needs of all hemophilia patients.

Hemophilia gene therapy: first, do no harm

The introduction of adeno-associated virus-mediated, liver-directed gene therapy into the hemophilia treatment landscape brings not only great promise but also considerable uncertainty to a community that has a history punctuated by the devastating effects of HIV and hepatitis C virus. These infections were introduced into people with hemophilia through the innovation of factor concentrates in the 1970s and 1980s. Concentrates, heralded as a major advance in treatment at the time, brought devastation and death to the community already challenged by the complications of bleeding into joints, vital organs, and the brain. Over the past 5 decades, considerable advances in hemophilia treatment have improved the survival, quality of life, and participation of people with hemophilia, although challenges remain and health equity with their unaffected peers has not yet been achieved. The decision to take a gene therapy product is one in which an informed, holistic, and shared decision-making approach must be employed. Bias on the part of health care professionals and people with hemophilia must be addressed and minimized. Here, we review data leading to the regulatory authorization of valoctocogene roxaparvovec, an adeno-associated virus 5 gene therapy, in Europe to treat hemophilia A and etranacogene dezaparvovec-drlb in the United States and Europe to treat hemophilia B. We also provide an overview of the decision-making process and recommend steps that should be taken by the hemophilia community to ensure the safety of and optimal outcomes for people with hemophilia who choose to receive a gene therapy product.

Recombinant factor IX Fc prophylaxis reduces pain and increases levels of physical activity, with sustained, long-term improvements in patients with hemophilia B: post hoc analysis of phase III trials using patient-reported outcomes

Background

Pain is a common symptom of hemophilia that may adversely affect patients' quality of life (QoL). Previous post hoc analyses of prophylaxis with recombinant factor IX Fc fusion protein (rFIXFc) have been published for adults and adolescents, demonstrating improvements in health-related QoL (HRQoL) when assessed by the haemophilia-specific QoL (HaemAQoL) questionnaire.

Objective

To describe in depth the evolution of QoL, pain- and activity-related domains and questions for pediatric, adolescent, and adult patients with hemophilia B treated with rFIXFc prophylaxis.

Design

A post hoc analysis of data from a series of clinical trials.

Methods

This post hoc, long-term analysis assessed patient-reported outcomes (PROs) from the Kids B-LONG (NCT01440946: pediatric) and B-LONG (NCT01027364: adults and adolescents) parent studies and the B-YOND (NCT01425723: all age groups) extension study.

Results

Ninety-two adult and adolescent patients that started in the B-LONG study were assessed, with a median (range) duration of follow-up of 58.9 (0.0-78.4) months. The Haem-A-QoL total score was significantly reduced from baseline by 4.45 (p ⩽ 0.01), as were the subdomains 'physical health' (9.10; p = 0.001), 'sports and leisure' (11.25; p ⩽ 0.01), 'treatment' (2.69; p = 0.05), and 'view of self' (5.81; p = 0.002). Thirty pediatric patients that started in the Kids B-LONG study were assessed, with a median (min-max) duration of follow-up of 36.7 (9.0-59.9) months. The high level of satisfaction demonstrated by the PROs at baseline was maintained.

Conclusion

rFIXFc prophylaxis reduced perceived pain and increased levels of physical activity with sustained, long-term improvements in QoL in adult and adolescent patients with hemophilia B and maintained high QoL scores in pediatric patients.

Pharmacokinetics of recombinant factor VIII in adults with severe hemophilia A: fixed-sequence single-dose study of octocog alfa, rurioctocog alfa pegol, and efanesoctocog alfa

Background

Efanesoctocog alfa is a new class of factor (F) VIII replacement therapy designed to provide high sustained factor levels for longer by overcoming the von Willebrand factor half-life ceiling.

Objectives

To assess the pharmacokinetics and safety of standard half-life (octocog alfa) and extended half-life (rurioctocog alfa pegol) FVIIIs and efanesoctocog alfa.

Methods

This phase 1 study (NCT05042440; EudraCT 2021-000228-37) enrolled previously treated adult men with severe hemophilia A. Patients received sequential single 50-IU/kg doses of octocog alfa, rurioctocog alfa pegol, and efanesoctocog alfa after appropriate washout periods between each dose.

Results

Thirteen participants were enrolled. Geometric mean elimination half-life of octocog alfa, rurioctocog alfa pegol, and efanesoctocog alfa was 11.0, 15.4, and 43.3 hours, respectively, and area under the FVIII activity-time curve was 1670, 2820, and 10,100 IU × h/dL, respectively. Efanesoctocog alfa maintained mean FVIII activity levels of >40 IU/dL for up to 4 days and at ∼10 IU/dL on day 7. Corresponding times for >40 IU/dL and >10 IU/dL were <1 and <2 days, respectively, for octocog alfa and 1 day and <3 days, respectively, for rurioctocog alfa pegol. No serious treatment-emergent adverse events were reported for efanesoctocog alfa, and no inhibitor development to FVIII was detected.

Conclusion

Efanesoctocog alfa had 3- to 4-fold longer elimination half-life and 3- to 6-fold greater exposure (area under the FVIII activity-time curve, 6.03 and 3.57 folds) than octocog alfa and rurioctocog alfa pegol. Efanesoctocog alfa provided high sustained FVIII activity in the normal-to-near-normal range (>40 IU/dL) for up to 4 days after the dose and at ∼10 IU/dL on day 7.

Expectation and loss when gene therapy for haemophilia is not an option: An exigency sub-study

BACKGROUND

Qualitative studies have explored why people with haemophilia (PwH) might consider or forgo gene therapy, the impact it has had on those who have received it, and what support might be needed throughout the process. No studies have yet examined what withdrawal prior to transfection might mean for PwH and their families.

AIMS

To understand the experiences of PwH and their families of withdrawal from gene therapy and to understand what support mechanisms might be required.

METHODS

Qualitative interviews were conducted with people with severe haemophilia who consented to take part in a gene therapy study in the UK but either withdrew or were withdrawn before transfection.

RESULTS

Nine PwH and a family member were invited to this sub-study. Eight participants were recruited: six PwH (five haemophilia A and one haemophilia B) and two family members. Four participants were excluded from a study after consenting but before transfection, having failed to meet all the inclusion criteria; two withdrew after consenting but before transfection due to concerns including duration of factor expression and the time commitment involved in follow-up. The mean age of participants was 40.5 years (range 25-63 years). Two major themes emerged during the interviews: Expectation and loss.

CONCLUSIONS

PwH have many expectations about the difference gene therapy can make to their lives. Studies show that these expectations may not be fully realised. For those who have either withdrawn or been withdrawn from gene therapy, any expectations they had may now be unachievable. The nature of these expectations and the loss expressed by the participants indicate that support needs to be provided to help them and their families manage it.

Progress, and prospects in the therapeutic armamentarium of persons with congenital hemophilia. Defining the place for liver-directed gene therapy

In persons with congenital severe hemophilia A (HA) living in high-income countries, twice weekly intravenous infusions of extended half-life (EHL) factor VIII (FVIII) products, or weekly/biweekly/monthly subcutaneous injections of emicizumab are the gold standard home treatments to grant days without hurdles and limitations. Once weekly/twice monthly infusions of EHL Factor IX (FIX) products achieve the same target in severe hemophilia B (HB). Gene therapy, which is likely to be licensed for clinical use within 1-2 years, embodies a shift beyond these standards. At an individual patient level, a single functional gene transfer leads to a > 10-yr almost full correction of the hemostatic defect in HB and to a sustained (3-6-yrs) expression of FVIII sufficient to discontinue exogenous clotting factor administrations. At the doses employed, the limited liver toxicity of systemically infused recombinant adeno-associated virus (rAAV) vectors is documented by long-term (12-15 yrs) follow-ups, and pre-existing high-titer neutralizing antibodies to the AAV5 vector are no longer an exclusion criterion for effective transgene expression with this vector. A safe durable treatment that converts a challenging illness to a phenotypically curable disease, allows persons to feel virtually free from the fears and the obligations of hemophilia for years/decades. Along with patient organizations and health care professionals, communicating to government authorities and reimbursement agencies the liberating potential of this substantial innovation, and disseminating across the Centers updated information on benefits and risks of this strategy, will align expectations of different stakeholders and establish the notion of a potentially lifelong cure of hemophilia.

How to translate and implement the current science of gene therapy into haemophilia care?

Gene-based therapy opens an entirely new paradigm in managing people with haemophilia (PWH), offering them the possibility of a functional cure by enabling continuous expression of factor VIII (FVIII) or factor IX (FIX) after transfer of a functional gene designed to replace the PWH's own defective gene. In recent years, significant advances in gene therapy have been made, resulting in clotting factor activity attaining near-normal levels, as reflected by 'zero bleeding rates' in previously severely inflicted patients following a single administration of adeno-associated viral (AAV) vectors. While this new approach represents a major advancement, there are still several issues that must be resolved before applying this technology in clinical practice. First, awareness, communication, and education about the therapeutic potential and modalities of gene therapy must be further strengthened. To this end, objective, unbiased, transparent, and regularly updated information must be shared, in an appropriate way and understandable language with the support of patients' organizations. Second, healthcare providers should adopt a patient-centred approach, as the 'one size fits all' approach is inappropriate when considering gene therapy. Instead, a holistic patient view taking into account their physical and mental dimensions, along with unexpressed expectations and preferences, is mandatory. Third, the consent procedure must be improved, ensuring that patients' interests are maximally protected. Finally, gene therapy is likely to be first delivered in a few centres, with the highest expertise and experience in this domain. Thus, patients should be managed based on a hub-and-spoke model, taking into account that the key to gene therapy's success lies in an optimal communication and collaboration both within and between haemophilia centres sharing their experiences in the frame of international registries. This review describes recent progress and explains outstanding hurdles that must be tackled to ease the implementation of this paradigm-changing new therapy.

RNAi for the Treatment of People with Hemophilia: Current Evidence and Patient Selection

Severe hemophilia is associated with spontaneous, prolonged and recurrent bleeding. Inadequate prevention and treatment of bleeding can lead to serious morbidity and mortality. Due to the limitations of intravenous clotting factor replacement, including the risk of inhibitory antibodies, innovative novel therapies have been developed that have dramatically changed the landscape of hemophilia therapy. Ribonucleic acid interference (RNAi) has brought the opportunity for multiple strategies to manipulate the hemostatic system and ameliorate the bleeding phenotype in severe bleeding disorders. Fitusiran is a RNAi therapeutic that inhibits the expression of the natural anticoagulant serpin antithrombin. Reduction in antithrombin is known to cause thrombosis if coagulation parameters are otherwise normal and can rebalance hemostasis in severe hemophilia. Reports from late stage clinical trials of fitusiran in hemophilia A and B participants, with and without inhibitory antibodies to exogenous clotting factor, have demonstrated efficacy in preventing bleeding events showing promise for a future "universal" prophylactic treatment of individuals with moderate-severe hemophilia.