Erratum: AAV vector production: Troublesome host innate responses in another setting.

[This corrects the article DOI: 10.1016/j.omtm.

Design of experiments as a decision tool for cell therapy manufacturing.

Background Aims: Cell therapies are costlier to manufacture than small molecules and protein therapeutics because they require multiple manipulations and are often produced in an autologous manner. Strategies to lower the cost of goods to produce a cell therapy could make a significant impact on its total cost.

Methods: Borrowing from the field of bioprocess development, the authors took a design of experiments (DoE)-based approach to understanding the manufacture of a cell therapy product in pre-clinical development, analyzing main cost factors in the production process.

The intersection of vector biology, gene therapy, and hemophilia.

Gene therapy is at the forefront of the drive to bring the potential of cure to patients with genetic diseases. Multiple mechanisms of effective and efficient gene therapy delivery (eg, lentiviral, adeno-associated) for transgene expression as well as gene editing have been explored to improve vector and construct attributes and achieve therapeutic success. Recent clinical research has focused on recombinant adeno-associated viral (rAAV) vectors as a preferred method owing to their naturally occurring vector biology characteristics, such as serotypes with specific tissue tropisms, facilitated in vivo delivery, and stable physicochemical properties.

Development of β-globin gene correction in human hematopoietic stem cells as a potential durable treatment for sickle cell disease.

Sickle cell disease (SCD) is the most common serious monogenic disease with 300,000 births annually worldwide. SCD is an autosomal recessive disease resulting from a single point mutation in codon six of the β-globin gene (). Ex vivo β-globin gene correction in autologous patient-derived hematopoietic stem and progenitor cells (HSPCs) may potentially provide a curative treatment for SCD.

Challenges Posed by Immune Responses to AAV Vectors: Addressing Root Causes.

Host immune responses that limit durable therapeutic gene expression and cause clinically significant inflammation remain a major barrier to broadly successful development of adeno-associated virus (AAV)-based human gene therapies. In this article, mechanisms of humoral and cellular immune responses to the viral vector are discussed. A perspective is provided that removal of pathogen-associated molecular patterns in AAV vector genomes to prevent the generation of innate immune danger signals following administration is a key strategy to overcome immunological barriers.

Quality Control Testing, Characterization and Critical Quality Attributes of Adeno-Associated Virus Vectors Used for Human Gene Therapy.

For adeno-associated virus (AAV)-based human gene therapy, challenges for the translation of promising research results to successful clinical development include optimization of vector design and manufacturing processes to ensure that vectors prepared for administration to human subjects have attributes consistent with safe and durable expression. This article briefly reviews quality control methods for routine testing and supplemental characterization of AAV vectors for investigational product development. The relationship of vector and manufacturing process design with product critical quality attributes is discussed.

Safety Assessment of AAV2-hGDNF Administered Via Intracerebral Injection in Rats for Treatment of Parkinson's Disease.

Glial cell line-derived neurotrophic factor (GDNF) is a potent neuroprotective biologic in Parkinson's disease models. Adeno-associated viral vector serotype 2 (AAV2)-human GDNF safety was assessed in rats treated with a single intracerebral dose of vehicle, 6.8 × 10, 6.

Timing of Intensive Immunosuppression Impacts Risk of Transgene Antibodies after AAV Gene Therapy in Nonhuman Primates.

Adeno-associated virus (AAV) vector gene therapy is a promising treatment for a variety of genetic diseases, including hemophilia. Systemic administration of AAV vectors is associated with a cytotoxic immune response triggered against AAV capsid proteins, which if untreated can result in loss of transgene expression. Immunosuppression (IS) with corticosteroids has limited transgene loss in some AAV gene therapy clinical trials, but was insufficient to prevent loss in other studies.

Efficacy, Safety, and Durability of Voretigene Neparvovec-rzyl in RPE65 Mutation-Associated Inherited Retinal Dystrophy: Results of Phase 1 and 3 Trials.

Purpose: To report the durability of voretigene neparvovec-rzyl (VN) adeno-associated viral vector-based gene therapy for RPE65 mutation-associated inherited retinal dystrophy (IRD), including results of a phase 1 follow-on study at year 4 and phase 3 study at year 2.

Design: Open-label phase 1 follow-on clinical trial and open-label, randomized, controlled phase 3 clinical trial.

Participants: Forty subjects who received 1.

Adeno-associated virus vectored immunoprophylaxis to prevent HIV in healthy adults: a phase 1 randomised controlled trial.

Background: A preventive vaccine for HIV is a crucial public health need; adeno-associated virus (AAV)-mediated antibody gene delivery could be an alternative to immunisation to induce sustained expression of neutralising antibodies to prevent HIV. We assessed safety and tolerability of rAAV1-PG9DP, a recombinant AAV1 vector encoding the gene for PG9, a broadly neutralising antibody against HIV.

Methods: This first-in-human, proof-of-concept, double-blind, phase 1, randomised, placebo-controlled, dose-escalation trial was done at one clinical research centre in the UK.

Retinal AAV8-RS1 Gene Therapy for X-Linked Retinoschisis: Initial Findings from a Phase I/IIa Trial by Intravitreal Delivery.

This study evaluated the safety and tolerability of ocular RS1 adeno-associated virus (AAV8-RS1) gene augmentation therapy to the retina of participants with X-linked retinoschisis (XLRS). XLRS is a monogenic trait affecting only males, caused by mutations in the RS1 gene. Retinoschisin protein is secreted principally in the outer retina, and its absence results in retinal cavities, synaptic dysfunction, reduced visual acuity, and susceptibility to retinal detachment.

Relative survival of patients with lymphoma in Queensland according to histological subtype.

Objective: To evaluate relative survival of patients in Queensland with different lymphoma subtypes; to determine whether outcomes have improved with recent changes in treatment; to evaluate relative survival according to place of residence and socio-economic status.

Design: Retrospective population-based study; analysis of data from the Oncology Analysis System, an online reporting tool for cancer incidence and outcomes in Queensland.

Participants: Patients over 15 years of age diagnosed with lymphoma in Queensland during 1993-2012.

Hemophilia B Gene Therapy with a High-Specific-Activity Factor IX Variant.

Background: The prevention of bleeding with adequately sustained levels of clotting factor, after a single therapeutic intervention and without the need for further medical intervention, represents an important goal in the treatment of hemophilia.

Methods: We infused a single-stranded adeno-associated viral (AAV) vector consisting of a bioengineered capsid, liver-specific promoter and factor IX Padua (factor IX-R338L) transgene at a dose of 5×10 vector genomes per kilogram of body weight in 10 men with hemophilia B who had factor IX coagulant activity of 2% or less of the normal value. Laboratory values, bleeding frequency, and consumption of factor IX concentrate were prospectively evaluated after vector infusion and were compared with baseline values.

Efficacy and safety of voretigene neparvovec (AAV2-hRPE65v2) in patients with RPE65-mediated inherited retinal dystrophy: a randomised, controlled, open-label, phase 3 trial.

Background: Phase 1 studies have shown potential benefit of gene replacement in RPE65-mediated inherited retinal dystrophy. This phase 3 study assessed the efficacy and safety of voretigene neparvovec in participants whose inherited retinal dystrophy would otherwise progress to complete blindness.

Methods: In this open-label, randomised, controlled phase 3 trial done at two sites in the USA, individuals aged 3 years or older with, in each eye, best corrected visual acuity of 20/60 or worse, or visual field less than 20 degrees in any meridian, or both, with confirmed genetic diagnosis of biallelic RPE65 mutations, sufficient viable retina, and ability to perform standardised multi-luminance mobility testing (MLMT) within the luminance range evaluated, were eligible.

Safety and durability of effect of contralateral-eye administration of AAV2 gene therapy in patients with childhood-onset blindness caused by RPE65 mutations: a follow-on phase 1 trial.

Background: Safety and efficacy have been shown in a phase 1 dose-escalation study involving a unilateral subretinal injection of a recombinant adeno-associated virus (AAV) vector containing the RPE65 gene (AAV2-hRPE65v2) in individuals with inherited retinal dystrophy caused by RPE65 mutations. This finding, along with the bilateral nature of the disease and intended use in treatment, prompted us to determine the safety of administration of AAV2-hRPE65v2 to the contralateral eye in patients enrolled in the phase 1 study.

Methods: In this follow-on phase 1 trial, one dose of AAV2-hRPE65v2 (1.

Effects of FVIII immunity on hepatocyte and hematopoietic stem cell-directed gene therapy of murine hemophilia A.

Immune responses to coagulation factors VIII (FVIII) and IX (FIX) represent primary obstacles to hemophilia treatment. Previously, we showed that hematopoietic stem cell (HSC) retroviral gene therapy induces immune nonresponsiveness to FVIII in both naive and preimmunized murine hemophilia A settings. Liver-directed adeno-associated viral (AAV)-FIX vector gene transfer achieved similar results in preclinical hemophilia B models.

Progress and challenges in viral vector manufacturing.

Promising results in several clinical studies have emphasized the potential of gene therapy to address important medical needs and initiated a surge of investments in drug development and commercialization. This enthusiasm is driven by positive data in clinical trials including gene replacement for Hemophilia B, X-linked Severe Combined Immunodeficiency, Leber's Congenital Amaurosis Type 2 and in cancer immunotherapy trials for hematological malignancies using chimeric antigen receptor T cells. These results build on the recent licensure of the European gene therapy product Glybera for the treatment of lipoprotein lipase deficiency.