Gene therapy for haemophilia

Gene doping and genomic science in sports: where are we?

The misuse of sport-related gene transfer methods in elite athletes is a real and growing concern. The success of gene therapy in the treatment of hereditary diseases has been most evident since targets in gene therapy products can be used in healthy individuals to improve sports performance. Performing these practices threatens the sporting character of competitions and may pose potential health hazards. Since the World Anti-Doping Agency pronouncement on the prohibition of such practices in 2003, several researchers have been trying to address the challenge of developing an effective method for the detection of genetic doping. This review presents an overview of the published methods developed for this purpose, the advantages and limitations of technologies and the putative target genes. At last, we present the perspective related to the application of the detection methods in the doping control field.

Gene therapy for haemophilia

BACKGROUND

Haemophilia is a genetic disorder characterized by spontaneous or provoked, often uncontrolled, bleeding into joints, muscles and other soft tissues. Current methods of treatment are expensive, challenging and involve regular administration of clotting factors. Gene therapy for haemophilia is a curative treatment modality currently under investigation. This is an update of a published Cochrane Review.

OBJECTIVES

To evaluate the safety and efficacy of gene therapy for treating people with haemophilia A or B.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis & Genetic Disorders Group's Coagulopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews. Date of last search: 17 April 2020.

SELECTION CRITERIA

Eligible trials include randomised or quasi-randomised clinical trials, including controlled clinical trials comparing gene therapy (with or without standard treatment) with standard treatment (factor replacement) or other 'curative' treatment such as stem cell transplantation for individuals with haemophilia A or B of all ages who do not have inhibitors to factor VIII or IX.

DATA COLLECTION AND ANALYSIS

No trials of gene therapy for haemophilia matching the inclusion criteria were identified.

MAIN RESULTS

No trials of gene therapy for haemophilia matching the inclusion criteria were identified.

AUTHORS' CONCLUSIONS

No randomised or quasi-randomised clinical trials of gene therapy for haemophilia were identified. Thus, we are unable to determine the safety and efficacy of gene therapy for haemophilia. Gene therapy for haemophilia is still in clinical investigation and there is a need for well-designed clinical trials to assess the long-term feasibility, success and risks of gene therapy for people with haemophilia.

Viral Vector-Based Delivery of CRISPR/Cas9 and Donor DNA for Homology-Directed Repair in an In Vitro Model for Canine Hemophilia B

Gene therapy represents an attractive alternative to treat hemophilia B. Here we established three hepatocyte-derived cell lines based on Huh7, PLC/PRF/5, and Hep3B cells stably carrying a mutated canine FIX (cFIXmut) transgene containing a single point mutation in the catalytic domain. Based on these in vitro models resembling a commonly used canine large animal model, the tetracycline-controlled transcriptional activator (Tet-on)-inducible CRISPR/Cas9 system and an optimized donor were used to correct mutated cFIX gene through homology-directed repair (HDR). For efficient delivery of designer nuclease and donor DNA, we produced a high-capacity adenovirus vector type 5 (HCAdV5) containing the Tet-on-inducible cFIX-specific CRISPR/Cas9 system and a single-stranded adeno-associated virus type 2 vector (ssAAV2) containing the modified donor. Moreover, we designed a single HCAdV5 delivering all components for HDR. Our amplification-refractory mutation system based on qPCR analysis (ARMS-qPCR) revealed that the single vector application in Huh7-cFIXmut cells resulted in up to 5.52% HDR efficiencies, which was superior to the two-vector strategy. Furthermore the single vector also resulted in increased phenotypic correction efficiencies assayed by ELISA. We conclude that HDR in combination with viral vector delivery holds great promise for the correction of mutated FIX in disease models.

Navigating Speed Bumps on the Innovation Highway in Hemophilia Therapeutics

The unprecedented emergence of novel therapeutics for both hemophilia A and B during the last half decade has been accompanied by the promise of even more extraordinary progress in ameliorative and curative strategies for both disorders. Paradoxically, the speed of innovation has created new dilemmas for persons with hemophilia and their physicians with respect to optimizing individual choices from the expanding menu of standard and novel therapies and approaches to symptom or risk reduction, and ultimately, to normalizing the hemophilia phenotype. Among the most disruptive new approaches, challenges remain in the form of the adverse reactions that have been observed with nonfactor therapies, as well as in the uncertain long-term safety profile of potentially curative gene therapy. Together, these challenges have generated uncertainty as to how to adopt novel therapies and treatment strategies across a diverse patient population, creating speed bumps on the hemophilia innovation highway. It is from this perspective that this article discusses the current state of gene therapy and bleeding prophylaxis for hemophilia A and B, as well as prevention and treatment of the factor VIII inhibitor phenotype in hemophilia A. It further posits that these speed bumps may provide important clues to the mechanistic understanding of both symptom manifestation and resilience within the hemophilia phenotype, as well as opportunities to reconsider and reconfigure the current paradigms for symptom prediction and individualized therapeutic decision making.

Recombinant adenovirus expressing a dendritic cell-targeted melanoma surface antigen for tumor-specific immunotherapy in melanoma mice model

Viral vectors represent a potential strategy for the treatment of human malignant tumors. Currently, recombinant adenovirus vectors are commonly used as gene therapy vehicles, as it possesses a proven safety profile in normal human cells. The recombinant adenovirus system has an ability to highly express exogenous genes and increase the stability of the carrier, which is only transiently expressed in the host cell genome, without integrating. Malignant melanoma cells are produced by the skin, and melanocyte tumors that exhibit higher malignant degrees lead to earlier transfer and higher mortality. In the present study, a recombinant adenovirus (rAd) was generated to express Anti-programmed death-1 (rAd-Anti-PD-1) and used to investigate the efficacy in melanoma cells and tumors. The results demonstrated that B16-F10 cell growth was significantly inhibited and the apoptosis incidence rate was markedly promoted following rAd-PD-1 treatment. The present study demonstrated that the production of α and β interferon was increased, which led to the induction of dendritic cell (DCs) maturation in rAd-anti-PD-1-treated mice. The present study indicated that rAd-anti-PD-1 exhibited the ability to generate more cluster of differentiation (CD)4⁺CD8⁺ T cells and induce a PD-1-specific cytotoxic T lymphocyte through DC-targeted surface antigens in mice. This resulted in a further enhanced recognition of melanoma cells due to DCs being targeted by the rAd-anti-PD-1-encoded PD-1. Notably, mice treated with the rAd-anti-PD-1-targeted PD-1 demonstrated an improved protection compared with tumor-bearing mice from the challenge group treated with a recombinant gutless adenovirus and Anti-PD-1. In conclusion, the present study demonstrated that targeting the melanoma surface antigens via the rAd-anti-PD-1-infected tumor cells enhanced the ability of recombinant adenovirus to induce a potent tumor-inhibitory effect and antigen-specific immune response.