A preliminary application of a haemophilia value framework to emerging therapies in haemophilia

Gene Therapy in Hemophilia A: Achievements, Challenges, and Perspectives

Strides in advancements of care of persons with hemophilia include development of long-acting factor replacement therapies, novel substitution and hemostatic rebalancing agents, and most recently approved gene therapy. Several decades of preclinical and clinical trials have led to development of adeno-associated viral (AAV) vector-mediated gene transfer for endogenous production of factor VIII (FVIII) in hemophilia A (HA). Only one gene therapy product for HA (valoctocogene roxaparvovec) has been approved by regulatory authorities. Results of valoctocogene roxaparvovec trial show significant improvement in bleeding rates and use of factor replacement therapy; however, sustainability and duration of response show variability with overall decline in FVIII expression over time. Further challenges include untoward adverse effects involving liver toxicity requiring immunosuppression and development of neutralizing antibodies to AAV vector rendering future doses ineffective. Real-life applicability of gene therapy for HA will require appropriate patient screening, infrastructure setup, long-term monitoring including data collection of patient-reported outcomes and innovative payment schemes. This review article highlights the success and development of HA gene therapy trials, challenges including adverse outcomes and variability of response, and perspectives on approach to gene therapy including shared decision-making and need for future strategies to overcome the several unmet needs.

Outcomes and outcome measures

INTRODUCTION

Advances in haemophilia treatment have resulted in a near-normal life expectancy, lower burden of bleeding and treatment, and improved quality of life in high-income countries. Bleeding rate is approaching zero and novel parameters should be evaluated to assess the efficacy of treatment not only from the clinical point of view by using new methodologies (e.g. joint health assessment), but also from the patient's perspective (e.g. pain, quality of life, treatment satisfaction).

METHODS AND RESULTS

This approach should be aimed at combining objective clinical methodologies and patient-reported outcomes (PROs). However, some instruments used for assessing PROs are still suboptimal and not properly validated. Recent evidence suggests that these tools can take advantage from a more personalized designed approach and could be effectively improved and serve to facilitate the patient's self-evaluation. For other congenital bleeding disorders (BDs), a set of patient-relevant outcomes has been also defined that overlap substantially those of haemophilia, including bleeding, side effects and complications, and PROs, such as pain, physical functioning, impact on daily life including school and work and mental health. There is a growing focus on addressing women-specific outcomes in BDs, reflecting an increased awareness of the unique challenges faced by women in this context. However, the development of tailored tools is imperative to further advance the progress in managing women with BDs, ensuring more accurate monitoring and personalized care.

CONCLUSIONS

How incorporating these outcome measures in the process of approval of novel treatments for these disorders by regulatory authorities remains to be established.

Benefits and risks of non-factor therapies: Redefining haemophilia treatment goals in the era of new technologies

INTRODUCTION

Over the last decades progress in haemophilia treatment has been remarkable and prophylaxis with clotting factor concentrates in haemophilia A and B has been established as the standard of care in individuals with haemophilia and a severe bleeding phenotype. Besides clotting factor products with prolonged half-life non-factor therapies were developed which enable prophylaxis via subcutaneous administration. Factor VIIIa mimetics like emicizumab facilitate the coagulation pathway and are used in routine clinical practice for indivdiduals with haemophilia A. Rebalancing therapeutic agents like fitusiran, concizumab, marstacimab and serpin PC block the anticoagulant pathway and clinical trials using these products in individuals with haemophilia A and B are ongoing.

AIM AND METHODS

A narrative review to asess the benefits and risks of non-factor therapies taking in to account re-defined haemophilia treatment goals.

RESULTS

Prophylaxis for prevention of bleeds using non-factor products by subcutaneous administration is effective and results in reductions of bleeding episodes in individuals with haemophilia A or B with and without inhibitors. The treatment with emicizumab showed tolerable safety both in clinical trials and long-term real-world observations with few thrombotic events. In some clinical trials with rebalancing therapies (fitusiran and concizumab) thrombotic events occurred. Monitoring of the haemostatic function of novel therapies especially with concomitant haemostatic treatment is not yet established.

CONCLUSION

With the advent of novel therapeutic agents including factor concentrates with ultra-long half-life and improved FVIIIa mimetics aimed at raising the bar of protection into the non-hemophilic range redefinition of haemophilia treatment goals is eagerly needed.

Clinical efficacy of simoctocog alfa versus extended half-life recombinant FVIII concentrates in hemophilia A patients undergoing personalized prophylaxis using a matching-adjusted indirect comparison method

OBJECTIVES

We aimed to indirectly compare the efficacy of personalized prophylaxis with simoctocog alfa (Nuwiq®) versus three extended half-life (EHL) recombinant FVIII (rFVIII) concentrates.

METHODS

Treatment effects were compared using matching-adjusted indirect comparisons after matching individual patient-level baseline characteristics for simoctocog alfa (pharmacokinetic [PK]-guided personalized prophylaxis) against published aggregate personalized prophylaxis data for efmoroctocog alfa, damoctocog alfa pegol, and rurioctocog alfa pegol.

RESULTS

A higher percentage (p < .001) of patients with zero bleeds was found with simoctocog alfa compared with efmoroctocog alfa (75% vs. 45%), damoctocog alfa pegol (77% vs. 38%), and rurioctocog alfa pegol (target trough level 1%-3%; 78% vs. 42%). Similar efficacy was found comparing simoctocog alfa against rurioctocog alfa pegol 8%-12% (77% vs. 62%). The mean total annualized bleeding rate was lower (p < .001) with simoctocog alfa than damoctocog alfa pegol (1.5 vs. 4.9). Consistent with approved dosing, the mean FVIII weekly dose was higher (p < .001) for simoctocog alfa than efmoroctocog alfa, damoctocog alfa pegol, or rurioctocog alfa pegol 1%-3%, but lower (p < .001) than rurioctocog alfa pegol 8%-12%.

CONCLUSIONS

Indirect comparisons demonstrated that PK-guided, personalized prophylaxis with simoctocog alfa can lead to higher zero bleed rates compared with personalized EHL rFVIII concentrate regimens, albeit with higher weekly doses, and a lower percentage of patients treated twice weekly or less.

Gene therapy preferences and informed decision-making: Results from a National Hemophilia Foundation Community Voices in research survey

INTRODUCTION

To inform education and treatment discussions, it is important to understand how persons with haemophilia prefer to learn about and discuss new therapies and to identify variables that influence decision-making.

AIM

The aim of this study was to evaluate preferences and variables which influence decision-making related to gene therapy and other novel haemophilia therapies.

METHODS

An online survey was sent to men with severe haemophilia enrolled in the National Hemophilia Foundation Community Voices in Research online platform for patient-powered research.

RESULTS

One hundred four men completed the survey including 33% Hispanics, 96 who had had not gene therapy and 71/96 (74%) who were on prophylaxis. Ninety-five percent were somewhat or very familiar with gene therapy. Men with haemophilia obtain information about new therapies from several sources, most commonly their haemophilia treatment team, patient advocacy groups and self-study. Participants identified safety and efficacy as well as other educational needs to inform decision-making. Of those without prior gene therapy, 73% indicated a high likelihood of considering gene therapy. Hispanic ethnicity and government-issued insurance were associated with a higher likelihood of considering gene therapy as a treatment option.

CONCLUSION

Haemophilia Treatment Centers and patient advocacy groups must be able to educate persons with haemophilia about aspects of novel therapies which are important to the individual, especially short- and long-term safety and efficacy. Further research is needed to determine how patient activation and health literacy influence decision-making and how to achieve equitable access and valid informed consent for novel therapies.

Building the blueprint: Formulating a community-generated national plan for future research in inherited bleeding disorders

Introduction

Decades of inherited bleeding disorders (BD) research transformed severe haemophilia from a childhood killer to a disorder managed across a full lifespan for many in economically developed countries. Health equity, a life unimpaired by disease complications, however, remains unimaginable for most people with an inherited BD (PWIBD).

Aim

The National Hemophilia Foundation (NHF) and American Thrombosis and Hemostasis Network (ATHN) undertook the development of a community‐driven United States (US) National Blueprint for Inherited Bleeding Disorders Research to transform the experience of all PWIBD and those who care for them.

Methods

Extensive community consultations were conducted to identify the issues most important to PWIBD and those who love and care for them. Expert multidisciplinary teams distilled these key areas of need into prioritised research questions, and identified the resources and infrastructure required to pursue them. A summit was held to gather feedback and inform the detailed blueprint.

Results

Community‐prioritised research areas fell into three broad categories: issues common across inherited BDs, those specific to individual disorders, and issues of infrastructure and capacity. NHF State of the Science Research Summit discussions of the research questions derived from the community priorities by six working groups provided important input for the drafting of the research blueprint for the coming decades.

Conclusion

The inherited BD community came together to develop the US National Blueprint for Inherited Bleeding Disorders Research dedicated to transforming the lives of all PWIBD including innovating solutions for the rarest disorders and under‐represented populations.

Preparing for tomorrow: Defining a future agenda

Gene therapy will be the first long-term therapy with potential to produce a functional cure for haemophilia. As a single dose ('once-and-done') therapy with significant uncertainties regarding impact and duration of factor expression, flexibility and adaptability of (1) value framework, (2) health technology assessment (HTA) methodology, and (3) development of alternative payment models will be needed for adoption of this new technology and to facilitate transparent decision-making to support its implementation. The responsibility for each of these currently lies with distinct entities, underscoring a need for enhanced collaboration between all stakeholders, as expanded engagement by key stakeholders will be critical to optimizing the assessment of value, enabling an optimised approach to HTA, and opening receptivity to new and innovative payment models. This supplement issue describes important considerations for a gene therapy 'toolkit', highlighting key considerations for each of the aforementioned tools, which will be useful for guiding decision-making regarding gene therapy as a novel treatment modality. In this article, we outline how the tools presented in this supplement can be applied as part of a framework to address the requirements of the relevant stakeholders, including payers, manufacturers, treaters, and patients. The paper also provides an illustrative example of how to understand the features of alternative payment models depending on the organization of and payment for healthcare.

Is the world ready for gene therapy?

KEY POINTS OF CONSIDERATION

To prepare for the introduction of gene therapies in haemophilia care, healthcare frameworks for evaluation and valuation will need to evolve to address the unique requirements of current and future innovations for treating this rare disease. The papers in this supplement provide an insightful and comprehensive state-of-the-art assessment of these requirements and challenges. In terms of evaluation, the definition of a patient-defined value framework that captures multi-dimensional, patient-centered outcomes is an important first step for determining the full benefit of gene therapy for persons with haemophilia. In terms of valuation and rewards for innovation, health systems will need to develop alternative payment models for risk-sharing that will allow payers and society to address uncertainties about the ultimate clinical and economic value of these innovations. And health technology assessment authorities will need to exercise greater flexibility in evidence requirements given the unique features of data collection for a potentially curative therapy for a rare disease with long-term uncertainties about durability of impact. Collaboration among stakeholders will be essential for developing the critical evidence requirements and providing the incentives needed to achieve sustainable budgets and broad access for persons with haemophilia worldwide.