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Evaluating the impact of systemic AAV9.cIDUA administration on brain pathology in MPS I dogs
S20
Abstracts / Molecular Genetics and Metabolism 114 (2015) S11–S130
support the long-term benefits of ERT with agalsidase alfa for Fabry disease in slowing the progression of renal impairment and cardiomyopathy. Treatment also appeared to delay onset of morbidity and mortality. Further clinical evaluation will be required to confirm these results. References: 1. Kampmann et al. Int J Cardiol 2008;130:367–73 2. Schiffmann et al. Nephrol Dial Transplant 2009; 24:2102–11 3. Banikazemi et al. Ann Intern Med 2007;146:77–86 This study was funded by Shire.
25 Evaluating the impact of systemic AAV9.cIDUA administration on brain pathology in MPS I dogs Peter Bella, Brittney L. Gurdaa, Yanqing Zhua, Tracey Sikorab, Therese Ruaneb, Patricia O'Donnellb, Mark E. Haskinsb, James M. Wilsona, a University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA, bUniversity of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
doi:10.1016/j.ymgme.2014.12.025
UN
CO
RR
EC
TE
DP
Nonsense suppression therapy is a therapeutic approach that utilizes compounds with the ability to suppress translation termination at premature termination codons to restore partial levels of full-length protein. By restoring partial protein levels, nonsense suppression therapy may be used to alleviate a variety of genetic diseases in patients that carry a nonsense mutation. PTC124® (ataluren, trade name Translarna™) is a nonsense suppression drug that was discovered by PTC Therapeutics, Inc. PTC124 has an excellent safety profile and is currently being evaluated in clinical trials for the ability to alleviate cystic fibrosis and Duchenne muscular dystrophy in patients that carry a nonsense mutation. Furthermore, conditional marketing authorization by the European Medicines Agency (EMA) for the treatment of nonsense mutation Duchenne muscular dystrophy was recently granted. Mucopolysaccharidosis I (Hurler syndrome, MPS IH) represents a viable disease target for nonsense suppression therapy because: 1) nonsense mutations are prevalent (60–80%) in most MPS IH patient populations; 2) very small amounts of α-l-iduronidase activity (b 1% of normal) can greatly attenuate the MPS IH phenotype; and 3) nonsense suppression drugs such as PTC124 are small molecules that may penetrate tissues that are refractory to current MPS IH treatments (e.g., CNS, bone, and cornea). In the current study, we examined the ability of PTC124 to moderate the MPS IH phenotype using a knock-in Idua-W402X mouse model that carries a mutation corresponding to the IDUA-W402X nonsense mutation commonly found in MPS IH patients. Homozygous Idua-W402X mice recapitulate many of the biochemical, morphological, and functional defects found in MPS IH patients. We first utilized a NanoLuc nonsense suppression reporter system to determine the optimal concentration range of PTC124 in vitro. From these in vitro studies, we found that PTC124 has a bell-shaped dose response, consistent with historical data. We then used the optimal concentration range to treat mouse embryonic fibroblasts (MEFs) derived from IduaW402X mice. We found that PTC124 restored enough α-l-iduronidase activity in the MEFs to significantly reduce GAG accumulation. PTC124 again demonstrated a bell-shaped dose response in MEFs. Finally, PTC124 was administered orally to Idua-W402X mice for 2 weeks. We found that PTC124 significantly reduced GAG storage in the brain, heart, liver, lungs, and spleen, but not in the kidney. We also observed a bellshaped dose response for PTC124 in vivo. The observed bell-shaped dose response for PTC124 in vivo suggests that optimized administration conditions may make PTC124 a viable new nonsense suppression drug to treat the underlying cause of disease in MPS IH patients who carry a nonsense mutation.
OF
David M. Bedwella, Dan Wangb, Ellen M. Welchc, Kim M. Keelinga, aUAB, Birmingham, AL, United States, bUniversity of Massachusetts Medical School, Worcester, MA, USA, cPTC Therapeutic, Inc., South Plainfield, NJ, USA
RO
24 The nonsense suppression drug PTC124 restored alpha-l-iduronidase activity and reduces glycosaminoglycan accumulation in MPS IH mice carrying the Idua-W402X mutation
Gene therapy based on AAV vectors emerged as a promising platform for the correction of genetic diseases affecting both CNS and peripheral organs. We explored the potential of intravenous (IV) administration of AAV9 expressing alpha-l-iduronidase (IDUA) to correct CNS pathology in mucopolysaccharidosis type I (MPS I) mice and dogs. In initial studies, MPS I-KO mice received a high dose (5e13 GC/kg) of AAV9 expressing canine IDUA and stable expression levels were achieved as well as complete correction of storage lesions both in CNS and systemically. Based on these results we tested AAV9 IV administration in a large animal model for MPS I. Dogs affected with MPS I were injected with comparable doses (4e13 GC/kg) of AAV9.CMV.cIDUA at an age of about three months and evaluated until they were about seven months old. However, the studies in dogs did not recapitulate the findings in mice. Serum enzyme levels reached normal levels over the first two-weeks of study but then declined to lower levels although still above the level of untreated controls. Most non-CNS tissues analyzed had lower than normal IDUA activity levels with the exception of the heart with average levels about 40-fold over normal. Enzyme levels in the cerebral cortex, hippocampus, and cerebellum of treated dogs were barely detectable. The low IDUA serum levels however were still able to reduce glycosaminoglycan (GAG) tissue storage with values ranging from 50 to 97% of affected controls. Brain GAG was surprisingly reduced by ~ 30% compared to affected control animals. Despite this reduction in GAG levels, secondary storage material, including GM3 and cholesterol, were not impacted. In summary, this study demonstrates the difficulty in correcting MPS brain pathology by IV administration alone of the vector.
doi:10.1016/j.ymgme.2014.12.026
doi:10.1016/j.ymgme.2014.12.027
26 Skeletal involvement in Gaucher disease at MRI: What long-term evolution can we expect under enzyme replacement therapy Nadia Belmatouga, Benjamin Fedidab, Sebastien Touraineb, Jerôme Stirnemannc, Jean-Denis Laredob, David Petroverb, aUniversity Hospital, Paris Nord Val de Seine, Assistance Public-Hôpitaux de Paris Beaujon, Clichy, France, bUniversity Hospital Lariboisière AP-HP, Paris, France, cUniversity Paris Diderot, Bichat Hospital, AP-HP, Geneva, Switzerland The semiquantitative magnetic resonance imaging (MRI) bone marrow burden (BMB) score with inclusion of both axial and peripheral bone marrow is reproducible and easy to use in Gaucher disease (GD). Purpose: to study the long-term evolution of the bone marrow burden (BMB) score at MRI in patients with Gaucher disease (GD) under enzyme replacement therapy (ERT). Material and methods: forty patients (22 females, 18 males, sex ratio of female to male patients, 1.22:1) treated for type 1 GD in 38/40 (95%) and type III GD in 2/40 (5%), aged 46.1 ± 14 (range, 26–87), were retrospectively studied in a single institution (Gaucher disease referral center). Skeletal involvement was assessed using the BMB scores of the spine and femur. MRI examinations were performed between January 2003 and June 2014. The long-term evolution of
Abstracts / Molecular Genetics and Metabolism 114 (2015) S11–S130
support the long-term benefits of ERT with agalsidase alfa for Fabry disease in slowing the progression of renal impairment and cardiomyopathy. Treatment also appeared to delay onset of morbidity and mortality. Further clinical evaluation will be required to confirm these results. References: 1. Kampmann et al. Int J Cardiol 2008;130:367–73 2. Schiffmann et al. Nephrol Dial Transplant 2009; 24:2102–11 3. Banikazemi et al. Ann Intern Med 2007;146:77–86 This study was funded by Shire.
25 Evaluating the impact of systemic AAV9.cIDUA administration on brain pathology in MPS I dogs Peter Bella, Brittney L. Gurdaa, Yanqing Zhua, Tracey Sikorab, Therese Ruaneb, Patricia O'Donnellb, Mark E. Haskinsb, James M. Wilsona, a University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA, bUniversity of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
doi:10.1016/j.ymgme.2014.12.025
UN
CO
RR
EC
TE
DP
Nonsense suppression therapy is a therapeutic approach that utilizes compounds with the ability to suppress translation termination at premature termination codons to restore partial levels of full-length protein. By restoring partial protein levels, nonsense suppression therapy may be used to alleviate a variety of genetic diseases in patients that carry a nonsense mutation. PTC124® (ataluren, trade name Translarna™) is a nonsense suppression drug that was discovered by PTC Therapeutics, Inc. PTC124 has an excellent safety profile and is currently being evaluated in clinical trials for the ability to alleviate cystic fibrosis and Duchenne muscular dystrophy in patients that carry a nonsense mutation. Furthermore, conditional marketing authorization by the European Medicines Agency (EMA) for the treatment of nonsense mutation Duchenne muscular dystrophy was recently granted. Mucopolysaccharidosis I (Hurler syndrome, MPS IH) represents a viable disease target for nonsense suppression therapy because: 1) nonsense mutations are prevalent (60–80%) in most MPS IH patient populations; 2) very small amounts of α-l-iduronidase activity (b 1% of normal) can greatly attenuate the MPS IH phenotype; and 3) nonsense suppression drugs such as PTC124 are small molecules that may penetrate tissues that are refractory to current MPS IH treatments (e.g., CNS, bone, and cornea). In the current study, we examined the ability of PTC124 to moderate the MPS IH phenotype using a knock-in Idua-W402X mouse model that carries a mutation corresponding to the IDUA-W402X nonsense mutation commonly found in MPS IH patients. Homozygous Idua-W402X mice recapitulate many of the biochemical, morphological, and functional defects found in MPS IH patients. We first utilized a NanoLuc nonsense suppression reporter system to determine the optimal concentration range of PTC124 in vitro. From these in vitro studies, we found that PTC124 has a bell-shaped dose response, consistent with historical data. We then used the optimal concentration range to treat mouse embryonic fibroblasts (MEFs) derived from IduaW402X mice. We found that PTC124 restored enough α-l-iduronidase activity in the MEFs to significantly reduce GAG accumulation. PTC124 again demonstrated a bell-shaped dose response in MEFs. Finally, PTC124 was administered orally to Idua-W402X mice for 2 weeks. We found that PTC124 significantly reduced GAG storage in the brain, heart, liver, lungs, and spleen, but not in the kidney. We also observed a bellshaped dose response for PTC124 in vivo. The observed bell-shaped dose response for PTC124 in vivo suggests that optimized administration conditions may make PTC124 a viable new nonsense suppression drug to treat the underlying cause of disease in MPS IH patients who carry a nonsense mutation.
OF
David M. Bedwella, Dan Wangb, Ellen M. Welchc, Kim M. Keelinga, aUAB, Birmingham, AL, United States, bUniversity of Massachusetts Medical School, Worcester, MA, USA, cPTC Therapeutic, Inc., South Plainfield, NJ, USA
RO
24 The nonsense suppression drug PTC124 restored alpha-l-iduronidase activity and reduces glycosaminoglycan accumulation in MPS IH mice carrying the Idua-W402X mutation
Gene therapy based on AAV vectors emerged as a promising platform for the correction of genetic diseases affecting both CNS and peripheral organs. We explored the potential of intravenous (IV) administration of AAV9 expressing alpha-l-iduronidase (IDUA) to correct CNS pathology in mucopolysaccharidosis type I (MPS I) mice and dogs. In initial studies, MPS I-KO mice received a high dose (5e13 GC/kg) of AAV9 expressing canine IDUA and stable expression levels were achieved as well as complete correction of storage lesions both in CNS and systemically. Based on these results we tested AAV9 IV administration in a large animal model for MPS I. Dogs affected with MPS I were injected with comparable doses (4e13 GC/kg) of AAV9.CMV.cIDUA at an age of about three months and evaluated until they were about seven months old. However, the studies in dogs did not recapitulate the findings in mice. Serum enzyme levels reached normal levels over the first two-weeks of study but then declined to lower levels although still above the level of untreated controls. Most non-CNS tissues analyzed had lower than normal IDUA activity levels with the exception of the heart with average levels about 40-fold over normal. Enzyme levels in the cerebral cortex, hippocampus, and cerebellum of treated dogs were barely detectable. The low IDUA serum levels however were still able to reduce glycosaminoglycan (GAG) tissue storage with values ranging from 50 to 97% of affected controls. Brain GAG was surprisingly reduced by ~ 30% compared to affected control animals. Despite this reduction in GAG levels, secondary storage material, including GM3 and cholesterol, were not impacted. In summary, this study demonstrates the difficulty in correcting MPS brain pathology by IV administration alone of the vector.
doi:10.1016/j.ymgme.2014.12.026
doi:10.1016/j.ymgme.2014.12.027
26 Skeletal involvement in Gaucher disease at MRI: What long-term evolution can we expect under enzyme replacement therapy Nadia Belmatouga, Benjamin Fedidab, Sebastien Touraineb, Jerôme Stirnemannc, Jean-Denis Laredob, David Petroverb, aUniversity Hospital, Paris Nord Val de Seine, Assistance Public-Hôpitaux de Paris Beaujon, Clichy, France, bUniversity Hospital Lariboisière AP-HP, Paris, France, cUniversity Paris Diderot, Bichat Hospital, AP-HP, Geneva, Switzerland The semiquantitative magnetic resonance imaging (MRI) bone marrow burden (BMB) score with inclusion of both axial and peripheral bone marrow is reproducible and easy to use in Gaucher disease (GD). Purpose: to study the long-term evolution of the bone marrow burden (BMB) score at MRI in patients with Gaucher disease (GD) under enzyme replacement therapy (ERT). Material and methods: forty patients (22 females, 18 males, sex ratio of female to male patients, 1.22:1) treated for type 1 GD in 38/40 (95%) and type III GD in 2/40 (5%), aged 46.1 ± 14 (range, 26–87), were retrospectively studied in a single institution (Gaucher disease referral center). Skeletal involvement was assessed using the BMB scores of the spine and femur. MRI examinations were performed between January 2003 and June 2014. The long-term evolution of