Pre-clinical workup of lentiviral mediated stem cell gene therapy for mucopolysaccharidosis type IIIA

Abstracts / Molecular Genetics and Metabolism 114 (2015) S11–S130

(GFP) or SGSH and were able to achieve high levels of gene expression without adverse toxicity. A transduction efficiency of 70% or more was consistently achievable. The colony forming units (CFU) assay demonstrated no lineage skewing or toxicity of our SGSH lentiviral vector in human HSCs. Furthermore, we were able to achieve a 9 fold increase in SGSH enzyme activity in transduced human HSCs at a vector copy number of 0.73 ± 0.1. We have demonstrated low transformation frequency with our SGSH vector using the in vitro immortalisation assay, comparable to other lentiviral vectors currently in the clinic. In addition, incidence of splice-truncated vector is negligible in LV-CD11b-coSGSH allowing maximal titres of clinical grade GMP to be produced. Once safety and efficacy experiments with GMP grade LV-CD11b-coSGSH are complete we aim to commence a phase I/II clinical trial in MPS IIIA patients during 2016.

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doi:10.1016/j.ymgme.2014.12.076

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and a pharmaceutical researcher. Initially the goal was to create a virtual company that would then be able to apply for STTR and SBIR grants to work on treatments for MPS types C and D. In the space of 2 years we have built up collaborations with leading academics and industry and submitted multiple grant proposals. We were able to secure our first STTR recently and this sets the stage for our growth. All of our resources are spent on supporting research and development with minimal overhead as we leverage collaborative researchers and tools to ensure we reach our goal. We will describe our strategy and propose that alongside forming foundations, a patient driven company may be a useful vehicle to push for more translational research in a rare disease. We would encourage other parents and researchers to start a small company and learn from this experience. Due to the limited pool of funding for this disorder, enhanced collaboration between foundations, academics and companies facilitated by small companies like PN may prevent unnecessary redundancies and broaden the impact of the ongoing research efforts. Ultimately our goal is to deliver a treatment to the patient. We will summarize the current state of research for Sanfilippo syndrome and describe the path we have taken and the pros and cons of forming a company along with some recommendations. As we are just beginning PN we see our own collaboration as an experiment that if successful could be a useful model for other rare diseases.

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doi:10.1016/j.ymgme.2014.12.077

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doi:10.1016/j.ymgme.2014.12.075

74 Pre-clinical workup of lentiviral mediated stem cell gene therapy for mucopolysaccharidosis type IIIA

Deborah Elsteina, Neal Weinrebb, Nadia Belmatougc, Ida Schwartzd, Patrick Deegane, Dylan Supinaf, Lydie Renaultg, Ozlem Goker-Alpanh, a Gaucher Clinic, Shaare Zedek Medical Center, Hebrew UniversityHadassah Medical School, Jerusalem, Israel, bUniversity Research Foundation for Lysosomal Diseases, Coral Springs, FL, USA, cReferral Center for Lysosomal Diseases, Hôpitaux Universitaires Paris Nord Val de Seine, Clichy, France, dHospital de Clínicas de Porto Alegre, Porto Alegre, Brazil, eLysosomal Disorders Unit, Addenbrooke's Hospital, Cambridge, UK, fShire, Wayne, PA, USA, gShire, Zug, Switzerland, hLysosomal Disorders Unit & Center for Clinical Trials, O&O Alpan, LLC., Fairfax, VA, USA

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Stuart M. Ellisona, Ana Sergijenkoa, Alex Langford-Smitha, Kia LangfordSmitha, Fiona Wilkinsona, Rob Wynnb, Brian Biggera, aUniversity of Manchester, Manchester, UK, bManchester Children's Hospital, Manchester, UK

76 The need for disease-specific patient-reported outcome measures for lysosomal disorders

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Mucopolysaccharidosis IIIA (MPS IIIA) is a devastating neurodegenerative, lysosomal disease caused by mutations in the Nsulphoglucosamine sulphohydrolase (SGSH) gene. SGSH deficiency leads to an accumulation of highly sulphated heparan sulphate (HS) in the lysosomes of patients, resulting in cellular and organ dysfunction, most notably the brain. There are currently no treatments available for this disease. Enzyme replacement therapy is a potential therapeutic strategy, but is ineffective since enzyme cannot pass the blood brain barrier. Haematopoietic stem cell transplantation (HSCT) can circumvent this problem via monocyte trafficking and brain engraftment. Indeed, HSCT has been shown to be highly effective at correcting the brain in the similar HS disease MPS I, however this is not the case for MPS IIIA due to insufficient enzyme production. To overcome this issue we developed a stem cell gene therapy approach to boost SGSH enzyme levels. Our strategy was to design a lentiviral gene therapy vector overexpressing codon optimised SGSH specifically in bone marrow monocytes using a myeloid specific promoter (from the CD11b gene) to drive transgene expression (LV-CD11b-coSGSH). Using this approach we were able to correct MPS IIIA mice. Lentiviral HSCT corrected lysosomal compartment size, normalised GAG storage and neuroinflammation, significantly improved survival and increased SGSH enzyme activity to 472% of normal in bone marrow and 11% of normal in brain, correcting the MPS IIIA behavioural phenotype. Following successful proof-of-concept in the murine model, we are now preparing the therapy for a phase I/II clinical trial and performing the necessary pre-clinical workup experiments to prove safety and efficacy of the treatment in human bone marrow. We have successfully optimised transduction of human CD34+ HSCs with CD11b lentiviral vector encoding either green fluorescent protein

A patient-reported outcome (PRO) measure is “any report of the status of a patient's health condition that comes directly from the patient, without interpretation of the patient's response by a clinician or anyone else”1. Because many PROs are responsive to modest treatment effects, and statistical significance can be attained with relatively small sample sizes, they have utility in rare diseases. Generic PRO and health-related quality of life (HRQL) measures have been introduced as endpoints in clinical trials and surveillance registries in many lysosomal disorders (LSD). This is justified because patients can and should evaluate and report changes in their condition and overall quality of life. Equally, they should evaluate the degree to which their expectations of efficacy have been met when they have been compliant with a therapeutic intervention. While useful for some purposes, generic PRO cannot be expected to capture the full diseaserelated patient experience. They may miss disease-specific aspects, given the tremendous phenotypic heterogeneity and the intra-disease phenotypic variability of most LSD. Another factor limiting the utility of generic measures is the variable effectiveness of treatments, e.g., enzyme replacement therapy or pharmacological chaperone efficacy in Gaucher versus Fabry disease. Finally, for LSD with more than one treatment modality, the class effects of interventions are integral to HRQL assessment. For example, the side effects may offer limited use of oral substrate reduction therapies in patients with type 1 Gaucher disease, however, similar side effects may be tolerated in another