Gene therapy for Wiskott-Aldrich syndrome in a severely affected adult.

Until recently, hematopoietic stem cell transplantation was the only curative option for Wiskott-Aldrich syndrome (WAS). The first attempts at gene therapy for WAS using a ϒ-retroviral vector improved immunological parameters substantially but were complicated by acute leukemia as a result of insertional mutagenesis in a high proportion of patients. More recently, treatment of children with a state-of-the-art self-inactivating lentiviral vector (LV-w1.6 WASp) has resulted in significant clinical benefit without inducing selection of clones harboring integrations near oncogenes. Here, we describe a case of a presplenectomized 30-year-old patient with severe WAS manifesting as cutaneous vasculitis, inflammatory arthropathy, intermittent polyclonal lymphoproliferation, and significant chronic kidney disease and requiring long-term immunosuppressive treatment. Following reduced-intensity conditioning, there was rapid engraftment and expansion of a polyclonal pool of transgene-positive functional T cells and sustained gene marking in myeloid and B-cell lineages up to 20 months of observation. The patient was able to discontinue immunosuppression and exogenous immunoglobulin support, with improvement in vasculitic disease and proinflammatory markers. Autologous gene therapy using a lentiviral vector is a viable strategy for adult WAS patients with severe chronic disease complications and for whom an allogeneic procedure could present an unacceptable risk. This trial was registered at www.clinicaltrials.gov as #NCT01347242.

Outcomes following gene therapy in patients with severe Wiskott-Aldrich syndrome.

IMPORTANCE: Wiskott-Aldrich syndrome is a rare primary immunodeficiency associated with severe microthrombocytopenia. Partially HLA antigen-matched allogeneic hematopoietic stem cell (HSC) transplantation is often curative but is associated with significant comorbidity. OBJECTIVE: To assess the outcomes and safety of autologous HSC gene therapy in Wiskott-Aldrich syndrome. DESIGN, SETTING, AND PARTICIPANTS: Gene-corrected autologous HSCs were infused in 7 consecutive patients with severe Wiskott-Aldrich syndrome lacking HLA antigen-matched related or unrelated HSC donors (age range, 0.8-15.5 years; mean, 7 years) following myeloablative conditioning. Patients were enrolled in France and England and treated between December 2010 and January 2014. Follow-up of patients in this intermediate analysis ranged from 9 to 42 months. INTERVENTION: A single infusion of gene-modified CD34+ cells with an advanced lentiviral vector. MAIN OUTCOMES AND MEASURES: Primary outcomes were improvement at 24 months in eczema, frequency and severity of infections, bleeding tendency, and autoimmunity and reduction in disease-related days of hospitalization. Secondary outcomes were improvement in immunological and hematological characteristics and evidence of safety through vector integration analysis. RESULTS: Six of the 7 patients were alive at the time of last follow-up (mean and median follow-up, 28 months and 27 months, respectively) and showed sustained clinical benefit. One patient died 7 months after treatment of preexisting drug-resistant herpes virus infection. Eczema and susceptibility to infections resolved in all 6 patients. Autoimmunity improved in 5 of 5 patients. No severe bleeding episodes were recorded after treatment, and at last follow-up, all 6 surviving patients were free of blood product support and thrombopoietic agonists. Hospitalization days were reduced from a median of 25 days during the 2 years before treatment to a median of 0 days during the 2 years after treatment. All 6 surviving patients exhibited high-level, stable engraftment of functionally corrected lymphoid cells. The degree of myeloid cell engraftment and of platelet reconstitution correlated with the dose of gene-corrected cells administered. No evidence of vector-related toxicity was observed clinically or by molecular analysis. CONCLUSIONS AND RELEVANCE: This study demonstrated the feasibility of the use of gene therapy in patients with Wiskott-Aldrich syndrome. Controlled trials with larger numbers of patients are necessary to assess long-term outcomes and safety.

Generation and Clinical Application of Gene-Modified Autologous Epidermal Sheets in Netherton Syndrome: Lessons Learned from a Phase 1 Trial.

Netherton syndrome (NS) is a rare autosomal recessive skin disorder caused by mutations in SPINK5. It is a debilitating condition with notable mortality in the early years of life. There is no curative treatment. We undertook a nonrandomized, open-label, feasibility, and safety study using autologous keratinocytes transduced with a lentiviral vector encoding SPINK5 under the control of the human involucrin promoter. Six NS subjects were recruited, and gene-modified epithelial sheets were successfully generated in three of five subjects. The sheets exhibited expression of correctly sized lympho-epithelial Kazal-type-related inhibitor (LEKTI) protein after modification. One subject was grafted with a 20 cm2 gene-modified graft on the left anterior thigh without any adverse complications and was monitored by serial sampling for 12 months. Recovery within the graft area was compared against an area outside by morphology, proviral copy number and expression of the SPINK5 encoded protein, LEKTI, and its downstream target kallikrein 5, which exhibited transient functional correction. The study confirmed the feasibility of generating lentiviral gene-modified epidermal sheets for inherited skin diseases such as NS, but sustained LEKTI expression is likely to require the identification, targeting, and engraftment of long-lived keratinocyte stem cell populations for durable therapeutic effects. Important learning points for the application of gene-modified epidermal sheets are discussed.

Phase I study protocol for ex-vivo lentiviral gene therapy for the inherited skin disease, Netherton Syndrome.

Netherton syndrome (NS) is a serious inherited skin disorder caused by mutations in the gene SPINK5 (serine protease inhibitor Kazal type 5) which encodes for a serine protease inhibitor LEKTI (lymphoepithelial Kazal type-related inhibitor). Patients with NS have defective keratinization, hair shaft defects, recurrent infections, atopy and a predisposition to skin malignancies. Historically, one in ten infants has died before their first birthday. Currently there are no proven treatments to cure this condition. A SIN-lentiviral vector encoding the codon optimized SPINK5 gene under the control of a 572bp element derived from the human involucrin promoter (INVO) can confer compartment specific LEKTI expression in NS keratinocytes with restoration of normal skin architecture. Here we detail a study protocol for a phase I trial for feasibility and safety evaluations of autologous epidermal sheets generated from ex-vivo gene corrected keratinocyte stem cells, which will be grafted onto patients with mutation proven NS.

Phase I study protocol for ex vivo lentiviral gene therapy for the inherited skin disease, Netherton syndrome.

Netherton syndrome (NS) is a serious inherited skin disorder caused by mutations in the serine protease inhibitor Kazal type 5 gene (SPINK5), which encodes for a serine protease inhibitor lymphoepithelial Kazal type-related inhibitor (LEKTI). Patients with NS have defective keratinization, hair shaft defects, recurrent infections, atopy, and a predisposition to skin malignancies. Historically, 1 in 10 infants has died before their first birthday. Currently, there are no proven treatments to cure this condition. A SIN-lentiviral vector encoding the codon-optimized SPINK5 gene under the control of a 572 bp element derived from the human involucrin promoter can confer compartment-specific LEKTI expression in NS keratinocytes with restoration of normal skin architecture. Here we detail a study protocol for a phase I trial for feasibility and safety evaluations of autologous epidermal sheets generated from ex vivo gene-corrected keratinocyte stem cells, which will be grafted onto patients with mutation-proven NS.