2017 Clinical trials update: Innovations in hemophilia therapy

Subcutaneous Marzeptacog Alfa (Activated) for On-Demand Treatment of Bleeding Events in Subjects With Hemophilia A or B With Inhibitors

Marzeptacog alfa (MarzAA) is under development for subcutaneous treatment of episodic bleeds in patients with hemophilia A/B and was studied in a phase III trial evaluating MarzAA compared with standard-of-care (SoC) for on-demand use. The work presented here aimed to evaluate MarzAA and SoC treatment of bleeding events on a standardized four-point efficacy scale (poor, fair, good, and excellent). Two continuous-time Markov modeling approaches were explored; a four-state model analyzing all four categories of bleeding improvement and a two-state model analyzing a binarized outcome (treatment failure (poor/fair), and treatment success (good/excellent)). Different covariates impacting improvement of bleeding episodes as well as a putative relationship between MarzAA exposure and improvement of bleeding episodes were evaluated. In the final four-state model, higher baseline diastolic blood pressure and higher age (> 33 years of age) were found to negatively and positively impact improvement of bleeding condition, respectively. Bleeding events occurring in knees and ankles were found to improve faster than bleeding events at other locations. The covariate effects had most impact on early treatment success (≤ 3 hours) whereas at later timepoints (> 12 hours), treatment success was similar for all patients indicating that these covariates might be clinically relevant for early treatment response. A statistically significant relationship between MarzAA zero-order absorption and improvement of bleedings (P < 0.05) were identified albeit with low precision. No statistically significant difference in treatment response between MarzAA and intravenous SoC was identified, indicating the potential of MarzAA for treatment of episodic bleeding events with a favorable subcutaneous administration route.

Polymeric Nanoparticles and Nanogels: How Do They Interact with Proteins?

Polymeric nanomaterials, nanogels, and solid nanoparticles can be fabricated using single or double emulsion methods. These materials hold great promise for various biomedical applications due to their biocompatibility, biodegradability, and their ability to control interactions with body fluids and cells. Despite the increasing use of nanoparticles in biomedicine and the plethora of publications on the topic, the biological behavior and efficacy of polymeric nanoparticles (PNPs) have not been as extensively studied as those of other nanoparticles. The gap between the potential of PNPs and their applications can mainly be attributed to the incomplete understanding of their biological identity. Under physiological conditions, such as specific temperatures and adequate protein concentrations, PNPs become coated with a "protein corona" (PC), rendering them potent tools for proteomics studies. In this review, we initially investigate the synthesis routes and chemical composition of conventional PNPs to better comprehend how they interact with proteins. Subsequently, we comprehensively explore the effects of material and biological parameters on the interactions between nanoparticles and proteins, encompassing reactions such as hydrophobic bonding and electrostatic interactions. Moreover, we delve into recent advances in PNP-based models that can be applied to nanoproteomics, discussing the new opportunities they offer for the clinical translation of nanoparticles and early prediction of diseases. By addressing these essential aspects, we aim to shed light on the potential of polymeric nanoparticles for biomedical applications and foster further research in this critical area.

Long-term immunogenicity, efficacy and tolerability of simoctocog alfa in patients with severe haemophilia A who had completed the NuProtect study in previously untreated patients

BACKGROUND

The NuProtect study reported data on the immunogenicity, efficacy and tolerability of simoctocog alfa (Nuwiq^® ) in 108 previously untreated patients with severe haemophilia A planned to be treated for ≥100 exposure days or up to 5 years. The NuProtect-Extension study collected long-term prophylaxis data in children with severe haemophilia A.

METHODS

Patients who completed the NuProtect study according to the protocol were eligible for the NuProtect-Extension study, a prospective, multinational, non-controlled, Phase 3b study.

RESULTS

Of 48 patients who entered the extension study, 47 (median age 2.8 years) received prophylaxis with simoctocog alfa for a median of 24 months, with 82%-88% on a twice-weekly or less regimen. No patient developed FVIII inhibitors during the extension study. The median (IQR) annualized bleeding rate (ABR) during prophylaxis was 0 (0-0.5) for spontaneous bleeding episodes (BEs) and 1.00 (0-1.95) for all BEs. ABRs estimated using a negative binomial model were .28 (95% CI: .15, .53) for spontaneous and 1.62 (95% CI: 1.09, 2.42) for all BEs. During the median follow-up of 24 months, 34 (72%) patients had zero spontaneous BEs and 46 (98%) had zero spontaneous joint BEs. Efficacy in treating BEs was excellent or good for 78.2% of rated BEs, and efficacy of surgical prophylaxis was excellent for two rated surgeries. No treatment-related adverse events were reported.

CONCLUSION

No FVIII inhibitors developed during long-term prophylaxis in the NuProtect-Extension study. Prophylaxis with simoctocog alfa was efficacious and well-tolerated, and is therefore an attractive long-term option for children with severe haemophilia A.

Application of Gene Therapy in Hemophilia

Gene therapy refers to introducing normal exogenous genes into target cells to correct or compensate for the diseases caused by defective and abnormal genes for the purpose of therapy. It holds out hope of a cure for single-gene genetic diseases such as thalassemia, hemophilia, etc. At present, gene therapy is performed in two ways: introducing exogenous genes, and gene editing. A great number of clinical trials of gene therapy in hemophilia have been carried out using viral vectors to introduce foreign genes into target cells. However, the production of neutralizing antibodies following injection and the inability to prepare viral vectors in large quantities limit their application. Although gene-editing methods like CRISPR avoid the above problems, the potential risks of off-target effects are still unknown. More trials and evidence are needed to elucidate the safety and accuracy of gene therapy. This paper will review the bench and clinical work of gene therapy in hemophilia in recent years, and summarize the challenges and prospects of gene therapy, so as to provide directions for future scientific research in this field.

Untreated bleeds in people with hemophilia A in a noninterventional study and intrapatient comparison after initiating emicizumab in HAVEN 1-3

Background

Bleeding in people with hemophilia A can be life threatening, and intra-articular bleeds can result in joint damage. Most clinical studies focus on treated bleeds, while bleeds not treated with coagulation factor(s) (untreated bleeds) are underreported.

Objectives

We assessed the incidence of untreated bleeds during a noninterventional study (NIS) wherein people with hemophilia A, with or without factor VIII (FVIII) inhibitors, were managed according to standard practice.

Patients/Methods

Using the Bleed and Medication Questionnaire, we prospectively collected data from three cohorts: Cohort A, adults/adolescents (age ≥12 years) with FVIII inhibitors; Cohort B, children (aged <12 years) with FVIII inhibitors; Cohort C, adults/adolescents without FVIII inhibitors. Untreated bleeds were analyzed for site, frequency, and etiology of bleeding and compared with those during emicizumab prophylaxis in the same individuals after transferring to a Phase III HAVEN trial.

Results

In the 221 participants enrolled in the NIS (Cohort A, n = 103; Cohort B, n = 24; Cohort C, n = 94), the incidence of untreated bleeds was approximately 40% of all bleeds in people with FVIII inhibitors and 26.2% in adolescents/adults without inhibitors. Approximately 70% of treated bleeds and approximately 54% of untreated bleeds in adults/adolescents were in joints. Untreated joint bleeds were less common (7.1%) in children. Overall, intra-individual comparisons showed reduced treated/untreated bleeds following transition from standard to emicizumab prophylaxis.

Conclusion

A significant proportion of bleeding events are untreated in people with hemophilia A. There is a need to further understand why bleeds remain untreated and to capture such events in clinical studies.

Clinical trials for genetic diseases in Latin America

Latin American geneticists have been contributing to the scientific development of Human and Medical Genetics fields since the early 1950s. In the last decades, as Medical Genetics is moving toward a new era of innovative therapies for previously untreatable conditions, the participation of Latin America in clinical trials is also increasing. This review discusses the particularities regarding funding, regulatory, and ethical aspects of conducting clinical trials for genetic diseases in Latin America, with an especial focus on Brazil, the largest country with the highest number of studies. Although there are still several barriers to overcome, the recent development of orphan drug legislation and policies for rare diseases in many Latin American countries indicates a growing opportunity for the participation of the region in international efforts for the development of new therapies for genetic diseases.

Subcutaneous engineered factor VIIa marzeptacog alfa (activated) in hemophilia with inhibitors: Phase 2 trial of pharmacokinetics, pharmacodynamics, efficacy, and safety

BACKGROUND

Marzeptacog alfa (activated) (MarzAA), a novel recombinant activated human factor VII (FVIIa) variant, was developed to provide increased procoagulant activity, subcutaneous (SC) administration, and longer duration of action in people with hemophilia.

OBJECTIVES

To investigate if daily SC administration of MarzAA in subjects with inhibitors can provide effective prophylaxis.

METHODS

This multicenter, open-label phase 2 trial (NCT03407651) enrolled men with severe congenital hemophilia with an inhibitor. All subjects had a baseline annualized bleeding rate (ABR) of ≥12 events/year. Subjects received a single 18 μg/kg intravenous dose of MarzAA to measure 24-hour pharmacokinetics (PK) and pharmacodynamics (PD), single 30 μg/kg SC dose to measure 48-hour PK/PD, then daily SC 30 μg/kg MarzAA for 50 days. If spontaneous bleeding occurred, the dose was sequentially escalated to 60, 90, or 120 μg/kg, with 50 days at the final effective dose without spontaneous bleeding to proceed to a 30-day follow-up. The primary end point was reduction in ABR. Secondary end points were safety, tolerability, and antidrug antibody (ADA) formation.

RESULTS

In the 11 subjects, the mean ABR significantly reduced from 19.8 to 1.6, and the mean proportion of days with bleeding significantly reduced from 12.3% to 0.8%. Of a total of 517 SC doses, six injection site reactions in two subjects were reported. No ADAs were detected. One fatal unrelated serious adverse event occurred: intracerebral hemorrhage due to untreated hypertension.

CONCLUSIONS

The data demonstrated that MarzAA was highly efficacious for prophylactic treatment in patients with inhibitors by significantly decreasing bleed frequency and duration of bleeding episodes.

Beliefs and Values About Gene Therapy and In-Utero Gene Editing in Patients with Hemophilia and Their Relatives

AIM

Hemophilia is an inherited disease for which current treatment is noncurative. While gene therapy and gene editing are being researched, we do not know how the hemophilia community perceives them. Herein, we explore the beliefs and values regarding these new therapies in patients with hemophilia and their relatives.

METHODS

This qualitative study used phone-based semi-structured interviews on 21 adult English-speaking patients with hemophilia A or B and their parents across the United States during March to July 2019. The study was advertised through different chapters of the Hemophilia Foundation. The interview guide included questions about participants' prior experience with hemophilia, and included two case scenarios about the use of gene therapy and in utero gene editing, after which participants were asked about their opinions, beliefs, and values on each scenario. We used a grounded theory approach and identified the main themes using an inductive process.

RESULTS

We interviewed 21 participants-12 patients and 9 mothers. Most of them had or were related to a patient with severe disease. The main themes discussed were related to efficacy, safety and financial concerns and insurance coverage for both gene therapy and in utero gene editing. Patients and their parents had expected outcomes in terms of durability of therapy and impact on emotional health and lifestyle changes in the long term. Gene therapy was more accepted among patients with severe and uncontrolled disease. In-utero gene editing was not completely accepted because of safety and ethical issues.

CONCLUSION

Patients with severe hemophilia perceive gene therapy as a potential cure, while gene editing was more controversial. Patients still have questions that remain to be answered regarding safety and efficacy that should be assessed with long-term follow up studies.

The Role of Physiotherapy in the New Treatment Landscape for Haemophilia

The physiotherapist plays an essential role for people with haemophilia, an inherited bleeding disease responsible for musculoskeletal complications. Yet, with the advent of new and advanced therapies, the medical landscape is changing, and physiotherapy must adapt alongside. This paper considers whether there will still be a need for physiotherapy in the era of advanced therapies, and discusses ways in which services should evolve to complement emerging treatment paradigms for haemostasis in people with haemophilia. Ultimately, physiotherapy will remain an important element of care, even for people with little joint damage and low risks in the era of the new mild phenotype. However, competencies will need to evolve, and physiotherapists in both primary care and specialist treatment centres should work with haematology colleagues to develop more sensitive tools for detecting early joint changes. Physiotherapists will also play a crucial role in counselling and physically coaching, monitoring the musculoskeletal status of people with haemophilia who have transitioned to new treatments.

Targeting of antithrombin in hemophilia A or B with investigational siRNA therapeutic fitusiran-Results of the phase 1 inhibitor cohort

BACKGROUND

Fitusiran, an investigational small interfering RNA therapy, reduces antithrombin production to rebalance hemostasis in people with hemophilia A or B, with or without inhibitors.

OBJECTIVES

To evaluate the safety and efficacy of fitusiran treatment for people with moderate/severe hemophilia A or B with inhibitors.

PATIENTS/METHODS

In this open-label phase 1, part D study, 17 males with hemophilia A or B with inhibitors received three once-monthly subcutaneous injections of fitusiran 50 mg (n = 6) or 80 mg (n = 11); followed for up to 112 days. Endpoints included safety (primary), pharmacokinetics/pharmacodynamics (secondary), annualized bleeding rate, and patient-reported outcomes (exploratory).

RESULTS

The most common adverse event was injection site erythema (n = 8). No thrombotic events were reported. At nadir, mean (standard error of the mean [SEM]) antithrombin activity decreased from baseline by 82.0% (2.2) and 87.4% (0.7) in the 50 mg and 80 mg groups, respectively. Antithrombin reduction was associated with increased thrombin generation. 11/17 (64.7%) participants had no bleeds during the observation period (mean [standard deviation] 69.4 [16.3] days). Mean (SEM) changes from baseline in Haemophilia Quality of Life Questionnaire for Adults total (-9.2 [2.9]) and physical health (-12.3 [3.9]) domain scores suggested clinically meaningful improvement.

CONCLUSIONS

Monthly fitusiran was generally well tolerated, lowered antithrombin levels from baseline, and resulted in improved thrombin generation. These preliminary results suggest that monthly fitusiran treatment may reduce bleeding episodes and improve quality of life in participants with hemophilia A or B with inhibitors.

Principles of care for acquired hemophilia

Objective

To establish clear priorities for the care of patients with acquired hemophilia A (AHA) by proposing 10 key principles of practical, holistic AHA management.

Method

These principles were developed by the Zürich Haemophilia Forum, an expert panel of European hemophilia specialists comprising physicians and nursing and laboratory specialists.

Results

The 10 proposed principles for AHA care are as follows: (a) Improving initial diagnosis of AHA; (b) Differential diagnosis of AHA: laboratory assessment of patients with unusual bleeding; (c) Effective communication between laboratories, physicians, and specialists; (d) Improving clinical care: networking between healthcare professionals in the treating hospital and specialist hemophilia centers; (e) Comprehensive assessment of bleeding; (f) Appropriate use of bypassing agents; (g) Long‐term follow‐up and monitoring for efficacy and safety of immunosuppressive treatment; (h) Inpatient/outpatient settings; (i) Access to innovative and disruptive treatments; (j) Promotion of international collaborative research.

Conclusion

The proposed principles for holistic AHA care aim to ensure swift diagnosis and optimal patient management. Key to achieving this goal is training for healthcare personnel in non‐specialist hospitals and collaboration between different specialists. We hope these principles will increase awareness of AHA in the wider medical community and catalyze efforts toward improving its practical, multidisciplinary management.

PHILEOS (haemoPHILia and ostEoporOSis) Study: protocol of a multicentre prospective case-control study

INTRODUCTION

Two meta-analyses showed lower bone mineral density (BMD) in patients with haemophilia (haemophilia type and severity were often not specified) compared with healthy controls. This finding could be related to reduced mobility and sedentary lifestyle, and/or hepatitis C or HIV infection. The aim of this study is to determine osteoporosis prevalence in patients with haemophilia classified in function of the disease type (A or B) and severity, and to evaluate the potential role of regular prophylactic factor replacement (early vs delayed initiation) in preserving or restoring BMD.

METHODS AND ANALYSIS

The haemoPHILia and ostEoporOSis Study is a prospective, controlled, multicentre study that will include patients in France (13 haemophilia treatment centres), Belgium (1 centre) and Romania (1 centre). In total, 240 patients with haemophilia and 240 matched healthy controls will be recruited (1:1). The primary objective is to determine osteoporosis prevalence in patients with severe haemophilia A and B (HA and HB) without prophylaxis, compared with healthy controls. Secondary outcomes include: prevalence of osteoporosis and osteopenia in patients with mild, moderate and severe HA or HB with prophylaxis (grouped in function of their age at prophylaxis initiation), compared with healthy subjects; BMD in patients with HA and HB of comparable severity; correlation between BMD and basal factor VIII/IX levels and thrombin potential; and quantification of plasmatic markers of bone remodelling (formation and resorption) in patients with haemophilia.

ETHICS AND DISSEMINATION

The protocol was approved by the French Ethics Committee and by the French National Agency for Medicines and Health Products Safety (number: 2019-A03358-49). The results of this study will be actively disseminated through scientific publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT04384341.

Generation of hyperfunctional recombinant human factor IX variants expressed in human cell line SK-Hep-1

OBJECTIVE

To develop recombinant factor IX (FIX) variants with augmented clotting activity.

RESULTS

We generated three new variants, FIX-YKALW, FIX-ALL and FIX-LLW, expressed in SK-Hep-1 cells and characterized in vitro and in vivo. FIX-YKALW showed the highest antigen expression level among the variants (2.17 µg^-mL), followed by FIX-LLW (1.5 µg^-mL) and FIX-ALL (0.9 µg^-mL). The expression level of FIX variants was two-five fold lower than FIX-wild-type (FIX-WT) (4.37 µg^-mL). However, the biological activities of FIX variants were 15-31 times greater than FIX-WT in the chromogenic assay. Moreover, the new variants FIX-YKALW, FIX-LLW and FIX-ALL also presented higher specific activity than FIX-WT (17, 20 and 29-fold higher, respectively). FIX variants demonstrated a better clotting time than FIX-WT. In hemophilia B mice, we observed that FIX-YKALW promoted hemostatic protection.

CONCLUSION

We have developed three improved FIX proteins with potential for use in protein replacement therapy for hemophilia B.

Safety and Efficacy of Turoctocog Alfa in the Prevention and Treatment of Bleeding Episodes in Previously Treated Patients from China with Severe Hemophilia A: Results from the Guardian 7 Trial

Purpose

Hemophilia care in China is characterized by widespread use of on-demand regimens and low-dose prophylaxis. With a limited number of approved recombinant factor VIII (FVIII) products, the incidence of arthropathy and disability in hemophilia patients remains high in China. The purpose of this trial was to evaluate the safety and efficacy of turoctocog alfa for prophylaxis and treatment of bleeding episodes in patients from China with severe hemophilia A across all age groups.

Patients and Methods

In this Phase 3, open-label trial, previously treated males of all ages with severe hemophilia A from China received turoctocog alfa for prophylaxis or on-demand treatment of bleeds. The primary endpoint was hemostatic effect for the treatment of bleeds during the main phase of the trial. Secondary endpoints included annualized bleeding rate during prophylaxis and the frequency of FVIII inhibitor development.

Results

Overall, 42 pediatric patients (age <12 years) and 26 adolescent/adult patients (≥12 years) were dosed with turoctocog alfa; 51 patients initiated treatment with prophylaxis, while 17 patients initiated on-demand treatment. During the main phase of the trial (6 months), hemostatic success was 95.1%. During the full trial (up to 24 months), hemostatic success was 95.4%; the overall median ABR was 1.18 bleeds/patient/year for prophylaxis patients; and 25 (51.0%) of 49 patients with target joints at baseline had all target joints resolved. No FVIII inhibitors (≥0.6 BU) were reported.

Conclusion

Turoctocog alfa was safe and effective for prophylaxis and treatment of bleeding episodes and for surgery in patients from China with severe hemophilia A across all ages.

Prophylaxis for hemophilia A without inhibitors: treatment options and considerations

INTRODUCTION

Hemophilia A is a bleeding disorder traditionally managed with standard half-life (SHL) factor (F) VIII concentrates. Extended half-life (EHL) FVIII products and emicizumab-kywh, a nonfactor therapy, are newer treatment options. Additional nonfactor agents and gene therapy are expected to reach the market in the near future.

AREAS COVERED

A PubMed (MEDLINE) search from 1962 to April 2020 related to hemophilia A, its management, and the products currently available for prophylaxis was performed to comprehensively review these topics and analyze the benefits and drawbacks of each therapeutic.

EXPERT OPINION

Prophylaxis with SHL FVIII concentrates remains the standard of care for patients with severe hemophilia A and may also be considered for selected individuals with moderate disease. Several years of real-world experience with EHL FVIII, emicizumab-kywh, and other agents in development will be necessary to determine their ultimate roles in the prevention of bleeding and its complications. Gene therapy may not provide a permanent cure for hemophilia A.

The clinical management of factor XI deficiency in pregnant women

INTRODUCTION

Factor XI (FXI) deficiency is associated with highly variable bleeding, including excessive gynecologic and obstetrical bleeding. Since approximately 20% of FXI-deficient women will experience pregnancy-related bleeding, careful planning and knowledge of appropriate hemostatic management is pivotal for their care.

AREAS COVERED

In this manuscript, authors present our current understanding of the role of FXI in hemostasis, the nature of the bleeding phenotype caused by its deficiency, and the impact of deficiency on obstetrical care. The authors searched PubMed with the terms, 'factor XI', 'factor XI deficiency', 'women', 'pregnancy', and 'obstetrics' to identify literature on these topics. Expectations of pregnancy-related complications in women with FXI deficiency, including antepartum, abortion-related, and postpartum bleeding, as well as bleeding associated with regional anesthesia are discussed. Recommendations for the care of these women are considered, including guidance for management of prophylactic care and acute bleeding.

EXPERT COMMENTARY

FXI deficiency results in a bleeding diathesis in some, but not all, patients, making treatment decisions and clinical management challenging. Currently available laboratory assays are not particularly useful for distinguishing patients with FXI deficiency who are prone to bleeding from those who are not. There is a need for alternative testing strategies to address this limitation.

Targeted inhibition of activated protein C by a non-active-site inhibitory antibody to treat hemophilia

Activated protein C (APC) is a plasma serine protease with antithrombotic and cytoprotective functions. Based on the hypothesis that specific inhibition of APC’s anticoagulant but not its cytoprotective activity can be beneficial for hemophilia therapy, 2 types of inhibitory monoclonal antibodies (mAbs) are tested: A type I active-site binding mAb and a type II mAb binding to an exosite on APC (required for anticoagulant activity) as shown by X-ray crystallography. Both mAbs increase thrombin generation and promote plasma clotting. Type I blocks all APC activities, whereas type II preserves APC’s cytoprotective function. In normal monkeys, type I causes many adverse effects including animal death. In contrast, type II is well-tolerated in normal monkeys and shows both acute and prophylactic dose-dependent efficacy in hemophilic monkeys. Our data show that the type II mAb can specifically inhibit APC’s anticoagulant function without compromising its cytoprotective function and offers superior therapeutic opportunities for hemophilia.

Activated protein C (APC) is a plasma serine protease with antithrombotic and cytoprotective functions. Here, the authors develop a monoclonal antibody that specifically inhibits APC’s anticoagulant function without compromising its cytoprotective function, and shows efficacy in animal models.

Exploring the Potential Feasibility of Intra-Articular Adeno-Associated Virus-Mediated Gene Therapy for Hemophilia Arthropathy

Hemophilia arthropathy (HA) represents the majority of morbidity in severe hemophilia patients, especially in resource-limited countries. Adeno-associated virus (AAV)-mediated gene therapy is showing promise for managing hemophilia. However, patients with neutralizing antibodies (NAbs) against AAV, and inhibitors to clotting factors, are excluded from such therapy. This study explored the feasibility of AAV-mediated local gene therapy for HA. Factor VIII knockout (FVIII^-/-) mice, with or without a FVIII inhibitor, were subjected to hemarthrosis induction and treated with either intravenous (IV) or intraarticular (IA) recombinant human factor VIII (rhFVIII). To investigate whether rhFVIII carried the risk to develop a FVIII inhibitor, FVIII^-/- mice were treated with three doses of IV or IA rhFVIII and inhibitor development was measured. In patients with established HA requiring synovial fluid aspiration, plasma, and synovial fluid were collected and measured for anti-AAV capsid IgG (serotypes 1-9 and 843) and NAbs for AAV843. IA rhFVIII provided better protection from synovitis compared with IV rhFVIII, with or without the FVIII inhibitor. While IV rhFVIII led to all FVIII^-/- mice developing an FVIII inhibitor (n = 31, median 4.9 Bethesda units [BU]/mL), only 50% of the mice developed a FVIII inhibitor by IA administration, and at a lower titer (median 0.55 BU/mL). In hemophilia patients, total anti-AAV IgG was lowest for AAV4 and AAV5, both in plasma and synovial fluid. Anti-AAV IgGs in synovial fluid for most samples were lower or similar to the plasma levels. These results show that direct IA rhFVIII administration yields better protection against bleeding-induced joint damage, even in the presence of an inhibitor antibody. IA rhFVIII delivery carried a lower risk of FVIII inhibitor formation compared with IV FVIII. The anti-AAV antibody level in synovial fluid was similar or lower than the plasma level, supporting the feasibility of local gene therapy for managing HA.

Direct Cytosolic Delivery of Proteins through Coengineering of Proteins and Polymeric Delivery Vehicles

Nanocarrier-mediated protein delivery is a promising strategy for fundamental research and therapeutic applications. However, the efficacy of the current platforms for delivery into cells is limited by endosomal entrapment of delivered protein cargo with concomitantly inefficient access to the cytosol and other organelles, including the nucleus. We report here a robust, versatile polymeric-protein nanocomposite (PPNC) platform capable of efficient (≥90%) delivery of proteins to the cytosol. We synthesized a library of guanidinium-functionalized poly(oxanorborneneimide) (PONI) homopolymers with varying molecular weights to stabilize and deliver engineered proteins featuring terminal oligoglutamate "E-tags". The polymers were screened for cytosolic delivery efficiency using imaging flow cytometry with cytosolic delivery validated using confocal microscopy and activity of the delivered proteins demonstrated through functional assays. These studies indicate that the PPNC platform provides highly effective and tunable cytosolic delivery over a wide range of formulations, making them robust agents for therapeutic protein delivery.

Exploring the Impact of Infusion Frequency in Hemophilia A: Exit Interviews with Patients Participating in BAY 94-9027 Extension Studies (PROTECT VIII)

INTRODUCTION

Prophylactic treatment of severe hemophilia A is burdensome, requiring frequent intravenous injections. Extended half-life (EHL) factor VIII replacement therapies offer longer intervals between infusions while still meeting efficacy and safety outcomes; however, patient perspectives following long-term use of such products in the real-world remain unknown.

OBJECTIVE

We aimed to explore the importance of infusion frequency and the potential benefits of reduced infusion frequency among patients receiving prophylactic treatment with an EHL product (BAY 94-9027).

METHODS

Patients with severe hemophilia A participating in the PROTECT VIII extension study were invited to participate in a semi-structured, concept elicitation 'exit' interview to discuss their experiences. Participants were recruited from Israel, The Netherlands, and the US. Interview transcripts were translated into English and analyzed using thematic analysis methods.

RESULTS

Sixteen participants (29-68 years of age) infusing with BAY 94-9027 once every 7 days, once every 5 days, or twice weekly were interviewed. Participants reported infusion frequency (alongside efficacy) as the most important treatment attribute influencing their satisfaction with therapy. Patient-reported benefits of reduced infusion frequency and longer duration of factor coverage included greater ability to participate in physical activities; better vein health; less time to schedule and administer factor VIII; reduced impact on work; and improved emotional well-being.

CONCLUSIONS

This study provides rich insights into the experiences of patients with EHL products and the value of reduced infusion frequency. Such data could be of value to a range of stakeholders (e.g. regulators, payers) and facilitate patient-clinician discussions to promote tailored treatment decisions.

Efficient nanocarriers of siRNA therapeutics for cancer treatment

Nanocarriers as drug delivery systems are promising and becoming popular, especially for cancer treatment. In addition to improving the pharmacokinetics of poorly soluble hydrophobic drugs by solubilizing them in a hydrophobic core, nanocarriers allow cancer-specific combination drug deliveries by inherent passive targeting phenomena and adoption of active targeting strategies. Nanoparticle-drug formulations can enhance the safety, pharmacokinetic profiles, and bioavailability of locally or systemically administered drugs, leading to improved therapeutic efficacy. Gene silencing by RNA interference (RNAi) is rapidly developing as a personalized field of cancer treatment. Small interfering RNAs (siRNAs) can be used to switch off specific cancer genes, in effect, "silence the gene, silence the cancer." siRNA can be used to silence specific genes that produce harmful or abnormal proteins. The activity of siRNA can be used to harness cellular machinery to destroy a corresponding sequence of mRNA that encodes a disease-causing protein. At present, the main barrier to implementing siRNA therapies in clinical practice is the lack of an effective delivery system that protects the siRNA from nuclease degradation, delivers to it to cancer cells, and releases it into the cytoplasm of targeted cancer cells, without creating adverse effects. This review provides an overview of various nanocarrier formulations in both research and clinical applications with a focus on combinations of siRNA and chemotherapeutic drug delivery systems for the treatment of multidrug resistant cancer. The use of various nanoparticles for siRNA-drug delivery, including liposomes, polymeric nanoparticles, dendrimers, inorganic nanoparticles, exosomes, and red blood cells for targeted drug delivery in cancer is discussed.

Clinical application of Web Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo): Patterns of blood sampling and patient characteristics among clinician users

BACKGROUND

Use of population pharmacokinetics (PopPK) to facilitate PK-informed prophylaxis in clinical practice has gained momentum among haemophilia providers due to the accessibility of tools such as the Web Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo) and availability of extended half-life (EHL) factor concentrates. It is unknown how clinicians implement PopPK.

AIM

To investigate the evolution of PopPK use in clinical practice by comparing blood sampling strategies, patient features, and factor group between initial and recent periods of WAPPS-Hemo availability.

METHODS

PK data for haemophilia A and haemophilia B patients from two time periods were extracted from the WAPPS-Hemo database: early availability (10/2015-09/2016) and recent use (10/2017-09/2018). We compared patient characteristics (age, body weight, haemophilia type), product type and dose, and blood sampling times between the time frames.

RESULTS

Over 1900 eligible infusions were submitted to WAPPS-Hemo during the periods studied, with 85% representing FVIII concentrates. In the recent cohort, PK profiles were requested for younger patients (median age 18 vs 26 years), with increased proportional EHL FVIII use (29% vs 14% of infusions). High-use centres generally submitted fewer blood samples per infusion than non-high-use centres, although the number of samples collected by non-high-use centres decreased significantly over time. During both periods, blood sample timing was generally consistent with ISTH recommended windows.

CONCLUSION

The use of WAPPS-Hemo by haemophilia providers grew by over threefold between the time periods investigated. While sampling times have included key time points proposed first by Björkman since early WAPPS-Hemo usage, a trend towards minimizing sampling was observed.

The rapidly evolving state of gene therapy

Gene therapy is emerging as a viable option for clinical therapy of monogenic disorders and other genetically defined diseases, with approved gene therapies available in Europe and newly approved gene therapies in the United States. In the past 10 years, gene therapy has moved from a distant possibility, even in the minds of much of the scientific community, to being widely realized as a valuable therapeutic tool with wide-ranging potential. The U.S. Food and Drug Administration has recently approved Luxturna (Spark Therapeutics Inc, Philadelphia, PA, USA), a recombinant adeno-associated virus (rAAV) 2 gene therapy for one type of Leber congenital amaurosis 2 ( 1 , 2 ). The European Medicines Agency (EMA) has approved 3 recombinant viral vector products: Glybera (UniQure, Amsterdam, The Netherlands), an rAAV vector for lipoprotein lipase deficiency; Strimvelis (Glaxo Smith-Kline, Brentford, United Kingdom), an ex vivo gammaretrovirus-based therapy for patients with adenosine deaminase-deficient severe combined immune deficiency (ADA-SCID); and Kymriah (Novartis, Basel, Switzerland), an ex vivo lentivirus-based therapy to engineer autologous chimeric antigen-receptor T (CAR-T) cells targeting CD19-positive cells in acute lymphoblastic leukemia. These examples will be followed by the clinical approval of other gene therapy products as this field matures. In this review we provide an overview of the state of gene therapy by discussing where the field stands with respect to the different gene therapy vector platforms and the types of therapies that are available.-Gruntman, A. M., Flotte, T. R. The rapidly evolving state of gene therapy.

Regional variation and cost implications of prescribed extended half-life factor concentrates among U.S. Haemophilia Treatment Centres for patients with moderate and severe haemophilia

BACKGROUND

Extended half-life (EHL) factor VIII (FVIII) and IX (FIX) products are intended to decrease the burden of prophylaxis for patients with haemophilia A or B. Whether these newer concentrates have led to meaningful clinical practice change remains vague.

AIM

To characterize the longitudinal use of standard (SHL) and EHL factor concentrates at haemophilia treatment centres (HTCs), using the ATHNdataset, a US database of 138 ATHN-affiliated HTCs.

METHODS

Factor concentrate use among moderate and severe haemophilia A and B patients without inhibitors was analysed at three time points over 18 months.

RESULTS

Use of EHL concentrates rose from 10% of patients to 22% during this study. EHL FVIII prophylaxis is prescribed to the minority of patients, 28%; EHL FIX now predominates for prophylaxis, 52%. Rates of prescribed EHL products varied significantly by age group and HTC region. Median prescribed prophylaxis for SHL compared to EHL products was FVIII 6240 and 5200 and FIX 6968 and FIX 3900 IU/kg/y, respectively. On-demand EHL use has grown but has minimal contribution to overall usage (2%).

CONCLUSION

Haemophilia treatment centre region and patient age impact the rate of adoption of EHL products; however, EHL prescribing continues to rise nationally, particularly for EHL FIX. Careful attention to annual cost of prophylaxis is imperative as the decrease in median EHL prophylaxis consumption is not offset by the higher unit cost of these products. It is unclear how further growth in use of EHLs will be impacted by emerging non-factor replacement and gene therapies.

From the voices of people with haemophilia A and their caregivers: Challenges with current treatment, their impact on quality of life and desired improvements in future therapies

Introduction

Haemophilia A is a chronic disease requiring frequent intravenous infusions of recombinant factor VIII. Previous studies have shown that challenges associated with current treatments may have significant impacts on quality of life (QoL) that are as important as the health outcomes conferred by the therapy. Emerging therapeutic innovations offer the potential to mitigate treatment‐related challenges, and it is therefore important to develop a better understanding of patient and caregiver experiences with existing haemophilia A treatments in order to characterize the full value of new treatments.

Aim

To gather firsthand perspectives from people with haemophilia A (PWHA) and caregivers on the challenges with current treatment, their impact on QoL and desired improvements in future therapies.

Methods

Qualitative insights were gathered from 20 non‐inhibitor PWHA or caregivers of PWHA across Canada through one‐on‐one interviews; insights were further explored through focus group sessions to uncover overarching themes and prioritize issues with current treatments.

Results

PWHA and caregivers identified several challenges, including administration of intravenous infusions, coordination of treatment schedules and ensuring adequate medication and supplies. Participants described how these challenges impact psychosocial well‐being, physical health, personal/social life and work. Alternate modes of administration and longer‐lasting treatment effects were identified as desired improvements over current treatments.

Conclusion

This study emphasizes the impact that existing haemophilia A treatments have on psychological well‐being, employment opportunities and adherence to treatment regimens. These considerations may help to inform decision‐making for policymakers and health systems around the true value of new therapies entering the haemophilia market.

Gene therapy in hemophilia A: a cost-effectiveness analysis

Gene therapy provides a potential phenotypic cure for hemophilia, yet the cost of this novel treatment is high, tempering enthusiasm and raising questions regarding cost vs benefit. To evaluate the cost-effectiveness of gene therapy treatment of severe hemophilia A compared with prophylaxis with factor VIII (FVIII), we developed a Markov state-transition model to estimate the costs and effectiveness of severe hemophilia A treatment strategies from a United States health care system perspective. Quality-adjusted life-years (QALYs) were the effectiveness measure. In the base case, hypothetical cohorts of 30-year-old patients received gene therapy or FVIII prophylaxis. We obtained model probabilities and utilities from the literature and costs from Medicare reimbursement data. One-way and probabilistic sensitivity analyses were performed to test the robustness of results. Over a 10-year time horizon, total per-person gene therapy strategy costs were $1.0M and resulted in 8.33 QALYs, whereas prophylaxis cost $1.7M and resulted in 6.62 QALYs. Thus, gene therapy dominated prophylaxis (costs less and was more effective). Gene therapy remained dominant unless initial costs exceeded $1.6M and were <$100 000 per 1 QALY gained compared with prophylaxis if initial costs were <$1.7M. Results were not sensitive to variation of all other parameters over clinically plausible ranges. In a probabilistic sensitivity analysis simultaneously varying all parameters 3000 times over parameter distributions, gene therapy was dominant in 92% of model iterations. Treatment of severe hemophilia A with gene therapy is likely to be cost-saving or cost-effective compared with FVIII prophylaxis.

Clinical utility of viscoelastic testing (TEG and ROTEM analyzers) in the management of old and new therapies for hemophilia

Hemophilia A and B are rare inherited bleeding disorders resulting from deficiency of coagulation factors VIII and IX respectively. In the past few decades, the field of hemophilia has witnessed pivotal management challenges and therapeutic advances. Routine coagulation and factor assays, while useful in the classification of severity and treatment monitoring in hemophilia patients, have been shown to be of limited use in managing clinical presentations and outcomes. This prompted the investigation of viscoelastic studies in hemophilia care, which have established their utility in various bleeding and thrombotic states. In this review, we will discuss and critically assess the current literature highlighting the use of viscoelastic studies in various aspects of hemophilia including the determination of clinical phenotype, management of patients with inhibitors, perioperative management, and monitoring of novel agents.

Update on clinical gene therapy for hemophilia

In contrast to other diverse therapies for the X-linked bleeding disorder hemophilia that are currently in clinical development, gene therapy holds the promise of a lasting cure with a single drug administration. Near-to-complete correction of hemophilia A (factor VIII deficiency) and hemophilia B (factor IX deficiency) have now been achieved in patients by hepatic in vivo gene transfer. Adeno-associated viral vectors with different viral capsids that have been engineered to express high-level, and in some cases hyperactive, coagulation factors were employed. Patient data support that sustained endogenous production of clotting factor as a result of gene therapy eliminates the need for infusion of coagulation factors (or alternative drugs that promote coagulation), and may therefore ultimately also reduce treatment costs. However, mild liver toxicities have been observed in some patients receiving high vector doses. In some but not all instances, the toxicities correlated with a T-cell response directed against the viral capsid, prompting use of immune suppression. In addition, not all patients can be treated because of preexisting immunity to viral capsids. Nonetheless, studies in animal models of hemophilia suggest that the approach can also be used for immune tolerance induction to prevent or eliminate inhibitory antibodies against coagulation factors. These can form in traditional protein replacement therapy and represent a major complication of treatment. The current review provides a summary and update on advances in clinical gene therapies for hemophilia and its continued development.

Prevention and Management of Bleeding Episodes in Patients with Acquired Hemophilia A

Acquired hemophilia A (AHA) is a rare autoimmune disease caused by autoantibodies inhibiting the function of coagulation factor VIII. It is characterized by spontaneous bleeding in patients with no previous family or personal history of bleeding. Although several large registries have collected clinical data on AHA, limited information is available on the optimal management of AHA because controlled clinical trials are lacking. AHA can easily be diagnosed if the problem (prolonged activated partial thromboplastin time in a bleeding patient) is recognized. After the effects of anticoagulants are excluded, low factor VIII activity and the detection of circulating inhibitors confirms the diagnosis. However, lack of familiarity with this rare condition may delay diagnosis and adequate therapy. Treatment of AHA is based on measures for prompt hemostatic control to stop (and prevent) bleeding, immunosuppression to eradicate the autoantibodies, and supportive care for the adverse effects of that treatment and patients' often complex comorbidities. This article gives a comprehensive overview of the current knowledge about the pathophysiology, diagnosis, and treatment of AHA.

The inhibitors - a challenge for the management of patients with hereditary haemophilia A

INTRODUCTION

Our research strategy was aimed at evaluating the possible implication of the type of factor VIII product administered as substitution treatment to haemophilia A patients in the occurrence of inhibitors and their consequences on the management.

METHODS

Scientific articles from July 2015 to July 2017 were searched using the PubMed and PubMed Central databases. The used search terms included "haemophilia A", "inhibitors", "plasma-derived factor VIII" and "recombinant factor VIII".

RESULTS

The risk factors for inhibitors occurrence may be patients-related (genetic and nongenetic) and treatment-related. The possibility of a correlation between the increased purity of factor VIII given as substitution treatment and the occurrence of inhibitors is discussed in the light of literature data. Plasma-derived factor VIII is less immunogenic, but not entirely safe from the point of view of the possibility of transmitting biological agents. It is obvious that there is not enough plasma-derived factor VIII for the planet's needs. Recombinant factor VIII products have revolutionized the treatment of patients with haemophilia A over the past 3 decades by the disappearance of transfusion-related infections and their complications. They are safer in terms of pathogens and the new long-acting factor VIII products are based on recombinant DNA technology.

CONCLUSION

Plasma-derived or recombinant factor VIII products must co-exist on the market for the benefit of haemophilic patients. Future solutions could be: less immunogenic factor VIII products, nonfactor replacement strategies, or bispecific antibody that mimics the function of coagulation factor VIII.

An Observational Study from Long-Term AAV Re-administration in Two Hemophilia Dogs

Adeno-associated virus (AAV) vectors have been successfully applied in hemophilia clinical trials. However, this approach is limited to patients without AAV-neutralizing antibodies (NAbs). In this study, we explored the feasibility of AAV re-administration in hemophilia A dogs treated initially 8 years ago with AAV8.canine FVIII. After the re-administration in two NAb-negative dogs with AAV8 vectors carrying human factor VIII (hFVIII), along with the proteasome inhibitor bortezomib, we observed a phenotypic improvement in both dogs that persisted in one dog. Phenotypic improvement disappeared at 59 days after re-administration in the other dog, and specific cytotoxic T lymphocytes (CTLs) to the capsid were detected at day 17, but not to hFVIII. hFVIII inhibitors were observed at day 59 and gradually increased. Mechanistic studies demonstrated an increase in pro-inflammatory cytokines, a decrease in immunomodulatory cytokines, as well as lower Tregs after re-administration. These results suggest that hFVIII inhibitor development may contribute to the therapeutic failure via immune response activation. Interestingly, it takes about 30–50 days for AAV NAb titers to decrease by half. Collectively, this study suggests that re-administration of the same AAV serotype after long-term follow-up is feasible and that the study of AAV NAb kinetics will provide important information for predicating the efficacy of re-administration.

The role of patient and healthcare professionals in the era of new hemophilia treatments in developed and developing countries

Medical decisions in hemophilia care are primarily related to the type of factor replacement and treatment regimen. With the growing number of treatment options for patients with hemophilia, decision making is more complex and requires careful consideration of benefits, risks, and patient goals. Shared decision making and decision-aid tools facilitate patient and healthcare provider communication. In this review, the overall role of shared decision making in medicine is outlined, with special emphasis on models for practical implementation. Examples of shared decision making in hemophilia are outlined, and application to new therapeutics is discussed through a case-based approach.

Shifting Landscape of Hemophilia Therapy: Implications for Current Clinical Laboratory Coagulation Assays

Clinical coagulation assays are an integral part of diagnosing and managing patients with hemophilia; however, in this new era of bioengineered factor products and non-factor therapeutics, problems have arisen with use of traditional coagulation tests for the quantification of several of these new products. Discussion over the use of one-stage clotting assays versus chromogenic substrate assays for clinical decision making and potency labeling has been ongoing for many years. Emerging factor concentrates have heightened concern over assay selection and availability. Emicizumab interferes with all aPTT based assays, rendering them unreliable and potentially falsely reassuring to the unaware provider. This review explores considerations for coagulation assays in the clinical setting and highlights how awareness of institutional coagulation assays and potential limitations have never been more critical for providers caring for patients with bleeding disorders. This article is protected by copyright. All rights reserved.

Evolving Complexity in Hemophilia Management

Rapid expansion of therapeutic options have increased the complexity of hemophilia care. Previously, on-demand therapy aimed to reduce morbidity and early mortality; however, now aggressive prophylaxis, particularly in children, encourages an active lifestyle. Accurate diagnosis, recognition of early threats to musculoskeletal health, and optimization of therapy are critical for both males and females affected by hemophilia. The diversity of emerging hemophilia therapies, from modified factor protein concentrates, to gene therapy, to nonfactor hemostatic strategies, provide an exciting opportunity to target unmet needs in the bleeding disorder community.

A Novel Approach to the Treatment of Plasma Protein Deficiency: Ex Vivo-Manipulated Adipocytes for Sustained Secretion of Therapeutic Proteins

Despite the critical need for lifelong treatment of inherited and genetic diseases, there are no developmental efforts for most such diseases due to their rarity. Recent progress in gene therapy, including the approvals of two products (Glybera and Strimvelis) that may provide patients with sustained effects, has shed light on the development of gene therapy products. Most gene therapy products are based on either adeno-associated virus-mediated in vivo gene transfer to target tissues or administration of ex vivo gene-transduced hematopoietic cells. In such circumstances, there is room for different approaches to provide clinicians with other therapeutic options through a variety of principles based on studies not only to gain an understanding of the pathological mechanisms of diseases, but also to understand the physiological functions of target tissues and cells. In this review, we summarize recent progress in gene therapy-mediated enzyme replacement and introduce a different approach using adipocytes to enable lifelong treatment for intractable plasma protein deficiencies.

Journey of siRNA: Clinical Developments and Targeted Delivery

Since the evolutionary discovery of RNA interference and its utilization for gene knockdown in mammalian cell, a remarkable progress has been achieved in small interfering RNA (siRNA) therapeutics. siRNA is a promising tool, utilized as therapeutic agent against various diseases. Despite its significant potential benefits, safe, efficient, and target oriented delivery of siRNA is one of the major challenges in siRNA therapeutics. This review covers major achievements in clinical trials and targeted delivery of siRNAs using various targeting ligand-receptor pair. Local and systemically administered siRNA drug candidates at various phases in clinical trials are described in this review. This review also provides a deep insight in development of targeted delivery of siRNA. Various targeting ligand-siRNA pair with complexation and conjugation approaches are discussed in this review. This will help to achieve further optimization and development in targeted delivery of siRNAs to achieve higher gene silencing efficiency with lowest siRNA dose availability.

Small Molecule Catalysts with Therapeutic Potential

Catalysts are employed in many areas of research and development where they combine high efficiency with often astonishing selectivity for their respective substrates. In biology, biocatalysts are omnipresent. Enzymes facilitate highly controlled, sophisticated cellular processes, such as metabolic conversions, sensing and signalling, and are prominent targets in drug development. In contrast, the therapeutic use of catalysts per se is still rather limited. Recent research has shown that small molecule catalytic agents able to modulate the redox state of the target cell bear considerable promise, particularly in the context of inflammatory and infectious diseases, stroke, ageing and even cancer. Rather than being "active" on their own in a more traditional sense, such agents develop their activity by initiating, promoting, enhancing or redirecting reactions between biomolecules already present in the cell, and their activity therefore depends critically on the predisposition of the target cell itself. Redox catalysts, for instance, preferably target cells with a distinct sensitivity towards changes in an already disturbed redox balance and/or increased levels of reactive oxygen species. Indeed, certain transition metal, chalcogen and quinone agents may activate an antioxidant response in normal cells whilst at the same time triggering apoptosis in cancer cells with a different pre-existing "biochemical redox signature" and closer to the internal redox threshold. In pharmacy, catalysts therefore stand out as promising lead structures, as sensor/effector agents which are highly effective, fairly selective, active in catalytic, i.e., often nanomolar concentrations and also very flexible in their structural design.

Targeting anticoagulant protein S to improve hemostasis in hemophilia

Improved treatments are needed for hemophilia A and B, bleeding disorders affecting 400 000 people worldwide. We investigated whether targeting protein S could promote hemostasis in hemophilia by rebalancing coagulation. Protein S (PS) is an anticoagulant acting as cofactor for activated protein C and tissue factor pathway inhibitor (TFPI). This dual role makes PS a key regulator of thrombin generation. Here, we report that targeting PS rebalances coagulation in hemophilia. PS gene targeting in hemophilic mice protected them against bleeding, especially when intra-articular. Mechanistically, these mice displayed increased thrombin generation, resistance to activated protein C and TFPI, and improved fibrin network. Blocking PS in plasma of hemophilia patients normalized in vitro thrombin generation. Both PS and TFPIα were detected in hemophilic mice joints. PS and TFPI expression was stronger in the joints of hemophilia A patients than in those of hemophilia B patients when receiving on-demand therapy, for example, during a bleeding episode. In contrast, PS and TFPI expression was decreased in hemophilia A patients receiving prophylaxis with coagulation factor concentrates, comparable to osteoarthritis patients. These results establish PS inhibition as both controller of coagulation and potential therapeutic target in hemophilia. The murine PS silencing RNA approach that we successfully used in hemophilic mice might constitute a new therapeutic concept for hemophilic patients.