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Gene Editing and Targeted Integration Using Zinc Finger Nucleases for Subjects with Mucopolysaccharidosis I (MPS I) NIH Recombinant DNA Advisory Committee December 4, 2015 Chester Whitley, PhD, MD, University of Minnesota Thomas Wechsler,

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Gene Editing and Targeted Integration Using Zinc Finger Nucleases for Subjects with Mucopolysaccharidosis I (MPS I)

NIH Recombinant DNA Advisory Committee December 4, 2015 Chester Whitley, PhD, MD, University of Minnesota Thomas Wechsler, PhD, Sangamo BioSciences, Inc. Scott McIvor, PhD, University of Minnesota

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Agenda

  • MPS I Clinical Background
  • Preclinical Overview

– ZFN technology and the albumin “safe harbor” locus approach – SB-318 IND-enabling nonclinical safety evaluation program – In vitro Evaluation of SB-318 in HepG2 cells

  • Clinical Protocol

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Agenda

  • MPS I Clinical Background
  • Preclinical Overview

– ZFN technology and the albumin “safe harbor” locus approach – SB-318 IND-enabling nonclinical safety evaluation program – In vitro Evaluation of SB-318 in HepG2 cells

  • Clinical Protocol

3

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Mucopolysaccharidosis Type I: Clinical Background

  • Lysosomal a-L-iduronidase enzyme metabolic defect
  • Nosology

Hurler syndrome Attenuated MPS I

Scheie syndrome Hurler-Scheie syndrome ‘Treated’ Hurler syndrome

  • Outcome of current treatments

Enzyme replacement therapy (ERT) Hematopoietic stem cell transplantation (HCST) Bone marrow transplantation (BMT) Umbilical cord transplantation (UCT)

  • Response of combined therapies

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Mucopolysaccharidosis Type I

  • Lysosomal a-L-iduronidase enzyme metabolic defect
  • Nosology

Hurler syndrome Attenuated MPS I

Scheie syndrome Hurler-Scheie syndrome ‘Treated’ Hurler syndrome

  • Outcome of current treatments

Enzyme replacement therapy (ERT) Hematopoietic stem cell transplantation (HCST) Bone marrow transplantation (BMT) Umbilical cord transplantation (UCT)

  • Response of combined therapies

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Lysosomal Storage Diseases – MPS I and MPS II

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Accumulation of GAGs like Dermatan and Heparan Sulfates in the lysosome of all tissues leads to dysfunction in several tissues in MPS I patients

Modified after Neufeld and Muenzer 2001

Glycoaminoglycans (GAGs)

a-L-Iduronidase (IDUA) in MPS I Iduronate 2-Sulfatase (IDS) in MPS II

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Mucopolysaccharidosis: Lysosomal inclusions

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Normal MPS I

Liver pathology in mucopolysaccharidosis (MPS) Disease

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Mucopolysaccharidosis Type I

  • Lysosomal a-L-iduronidase enzyme metabolic defect
  • Nosology

Hurler syndrome Attenuated MPS I

Scheie syndrome Hurler-Scheie syndrome ‘Treated’ Hurler syndrome

  • Outcome of current treatments

Enzyme replacement therapy (ERT) Hematopoietic stem cell transplantation (HCST) Bone marrow transplantation (BMT) Umbilical cord transplantation (UCT)

  • Response of combined therapies

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Mucopolysaccharidosis Type I

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Hurler-Scheie syndrome (MPS IHS) Scheie syndrome (MPS IS) Hurler syndrome (MPS IH) Hurler syndrome (MPS IH)

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Mucopolysaccharidosis Type I

  • Lysosomal a-L-iduronidase enzyme metabolic defect
  • Nosology

Hurler syndrome Attenuated MPS I

Scheie syndrome Hurler-Scheie syndrome ‘Treated’ Hurler syndrome

  • Outcome of current treatments

Enzyme replacement therapy (ERT) Hematopoietic stem cell transplantation (HCST) Bone marrow transplantation (BMT) Umbilical cord transplantation (UCT)

  • Response of combined therapies

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Orthopaedic Problems in MPS

  • Spine

– Kypophosis, scoliosis – Cervical cored compression

  • Upper extremity

– Carpal tunnel syndrome – Trigger digits

  • Lower extremity

– Hip dubluxations – Genu varum – Digital deformities

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Cervical Spinal Compression in a Patient with MPS

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Carpal Tunnel Syndrome

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  • Carpal Tunnel is a Fixed Size
  • Deposits of GAGs in

tendons/tissue around tendons

  • Enlarged carpal bones
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Median Nerve Compression

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Results in

  • Joint Stiffness
  • Loss of PIP flexion
  • Loss of DIP extension

Trigger Digits

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Hip Subluxation

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  • If untreated, will lead to
  • steoarthritis (OA) at

early age

  • OA in this age patient is

difficult to treat

  • X-ray of 18 yr old pt
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Genu Valgus Deformities

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  • “Knock-knees”
  • Previously: Proximal

Tibial stapling procedures

  • Staples: High

Complication Rate

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Mucopolysaccharidosis Type I: Outcome of Treatment

  • Lysosomal a-L-iduronidase enzyme metabolic defect
  • Nosology

Hurler syndrome Attenuated MPS I

Scheie syndrome Hurler-Scheie syndrome ‘Treated’ Hurler syndrome

  • Outcome of current treatments

Enzyme replacement therapy (ERT) Hematopoietic stem cell transplantation (HCST) Bone marrow transplantation (BMT) Umbilical cord transplantation (UCT)

  • Response of combined therapies

18

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Mucopolysaccharidosis Type I

  • Lysosomal a-L-iduronidase enzyme metabolic defect
  • Nosology

Hurler syndrome Attenuated MPS I

Scheie syndrome Hurler-Scheie syndrome ‘Treated’ Hurler syndrome

  • Outcome of current treatments

Enzyme replacement therapy (ERT) Hematopoietic stem cell transplantation (HCST) Bone marrow transplantation (BMT) Umbilical cord transplantation (UCT)

  • Response of combined therapies

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  • Twenty-two year old male
  • Transplanted at 18 months old
  • Twenty years later:
  • Full donor engraftment

confirmed by molecular studies

  • Donor levels of enzyme in

peripheral leukocytes

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Mucopolysaccharidosis: Poor Growth After HSCT

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Glycosaminoglycan Before and After Bone Marrow Transplant

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Citation Case At Diagnosis Reference Range** Ratio Post-HSCT* Reference Range** S

No. GAG/creatini ne (mg/g) GAG/creatini ne (mg/g) % Upper Limit GAG/creatini ne (mg/g) GAG/creatini ne (mg/g) % Upper Limit

Herskhovitz et al, 2009 1 7.0 5.0 140% 2 8.0 5.0 160% 3 107 5.0 713% 22.0 15.0 147% 4 56 15.0 373% 15.0 15.0 100% Hite et al,1999 and current 176 10.7 1,645% 7.6 6.5 117% MEAN 911% 133%

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Mucopolysaccharidosis Type IH: Neurogeneration

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Neurologic Deterioration in Hurler Syndrome

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The rate of decline in Hurler syndrome without hematopoietic stem cell transplant is about 20 points per year, i.e., IQ drops 1.6 points per month “The earlier the transplant, the better the cognitive

  • utcome”
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Developmental Quotient (DQ) Declines in Children with Hurler Syndrome during the First Year after Hematopoietic Stem Cell Transplantation

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  • During the initial post-transplant year, children with Hurler syndrome continue to

decline at the same rate as before.

  • After 1 year of donor engraftment, IQ remains stable.
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Neurologic Deterioration in Hurler Syndrome

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The rate of decline in Hurler syndrome without hematopoietic stem cell transplant is about 20 points per year, i.e., IQ drops 1.6 points per month “The earlier the transplant, the better the cognitive

  • utcome”

Would combining intravenous enzyme replacement therapy (ERT) with hematopoietic stem cell transplant (HCT) improve the cognitive outcome?

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Would Combining Intravenous Enzyme Replacement Therapy (ERT) with Hematopoietic Stem Cell Transplant (HCT) Improve the Cognitive Outcome?

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40 50 60 70 80 90 100 110 120 130

Baseline 2y post Baseline 2y post

Standard Score (100 ± 15)

Visual Reception

Transplant + ERT Transplant Alone Visual Problem Solving is better in the combined therapy (HCT + ERT) group compared to the HCT-alone group

Significantly different slopes 9.83 (5.57, 14.10) <0.001

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Mucopolysaccharidosis Type I

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Hurler-Scheie syndrome (MPS IHS) Scheie syndrome (MPS IS) Hurler syndrome (MPS IH) Hurler syndrome (MPS IH)

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Hurler-Scheie syndrome ERT Scheie syndrome ERT Hurler syndrome BMT Hurler syndrome ERT

Attenuated Mucopolysaccharidosis Type I

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Agenda

  • MPS I Clinical Background
  • Preclinical Overview

– ZFN technology and the albumin “safe harbor” locus approach – SB-318 IND-enabling nonclinical safety evaluation program – In vitro Evaluation of SB-318 in primary and transformed Hepatocytes

  • Clinical Protocol

45

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Technology Overview Engineered ZFN technology

3’ 5’ C C A A C G C G A A T T A T G G C G G C G T G C G C T T A A C G C A T G G G T G G T T G C G C T T A A T A C C G C C G C A C G C G A A T T G C G T A C C C A T A C A T G 3’ 5’

Nuclease

Heterodimeric FokI Nuclease Genomic DNA Sequence specific designed Zinc Finger Protein (ZFP1) ZFN = Designer restriction enzyme Sequence specific designed Zinc Finger Protein (ZFP2)

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ZFN mediated DNA double-strand break leads to targeted gene correction

Targeted Gene Addition / Gene Correction

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ZFN Technology and the Albumin “Safe Harbor” Locus Approach ZFN-Mediated Gene Therapy

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3’ 5’ C C A A C G C G A A T T A T G G C G G C G T G C G C T T A A C G C A T G G G T G G T T G C G C T T A A T A C C G C C G C A C G C G A A T T G C G T A C C C A T A C A T G 3’ 5’

Nuclease ZFN1 ZFN2

Genomic DNA

3’ 5’ C C A A C G C G A A T T A T G G G T T G C G C T T A A T A C C G C T A C A T G G C G T G C G C T T A A C G C A T G G G T A C G C G A A T T G C G T A C C C A 3’ 5’

Therapeutic Gene of Choice

3’ 5’ C C A A C G C G A A T T A T G G G T T G C G C T T A A T A C T A C A T G T G C G C T T A A C G C A T G G G T A C G C G A A T T G C G T A C C C A 3’ 5’

Albumin “safe harbor” locus

MPS I Gaucher / Fabry MPS II

  • Hemoph. B

SB-FIX SB-318

  • Therapeutic Gene of Choice

Therapeutic Gene of Choice

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Systemic Delivery of ZFP Therapeutics via AAV Allows in vivo Gene Correction of Monogenic Diseases

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Human albumin ZFN pair and therapeutic gene Packaged into AAV2/6 vectors for delivery into liver One-time intravenous (IV) administration

AAV Vectors

ZFN ZFN

Homology Therapeutic Gene Homology

Liver cells secrete therapeutic protein into bloodstream Cross correction of secondary tissues like spleen, heart lung and kidney

ZFN1 ZFN2

hIDUA

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Targeted Integration at the Albumin Locus Leads to High Transgene Expression

Albumin (the most abundant blood plasma protein) has all properties of an ideal In vivo Protein Replacement Platform gene:  Tissue specific and only produced in the liver  Safe to co-opt a small percentage of albumin  Very highly expressed relative to protein replacement therapies > Normal albumin levels in blood: 40-50 mg/mL ; Synthesis rate from liver: ~105 g/week

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A very small fraction of natural albumin synthesis is needed to drive therapeutic levels of the new protein

Disease: MPS I Gaucher Fabry ERT Dose: 43.5 50 37.5 (mg/week – 75kg patient) ERT Half life: 90-216 3.6-10.4 119±49 (minutes) % of Albumin production rate: 0.054% 0.063% 0.047%

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Targeted Integration at the Albumin Locus Leads to High Transgene Expression

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Albumin (the most abundant blood plasma protein) has all properties of an ideal In vivo Protein Replacement Platform gene:  Tissue specific and only produced in the liver  Safe to co-opt a small percentage of albumin  Very highly expressed relative to protein replacement therapies > Normal albumin levels in blood: 40-50 mg/ml ; Synthesis rate from liver: ~105 g /week

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Expression of hIDUA Protein from the Albumin Locus

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SB-318 IND-Enabling Nonclinical Safety Evaluation Program

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  • In Vitro Pharmacology Studies

– Proof-of-concept in mouse and human hepatocytes

  • In Vitro Safety Studies

– GLP soft agar transformation assay with SB-318 in human fibroblast cell line

 No in vitro transformation potential evident

– Off-target analysis: SELEX-guided assessment (mouse and human genomes) – Off-target analysis (unbiased): Oligo integration assay

  • In Vivo Pharmacology, Biodistribution and Toxicology Studies

– Wild-type C57BL/6 mice – Prevention and treatment models in MPS I mice – Cynomolgus monkeys

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In vivo Pharmacology/Toxicology Studies

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  • Surrogate ZFNs and hIDUA donor components required due to species-specific

differences in DNA sequences at the albumin intron 1 target locus

– Mouse – Cynomolgus monkey

  • Study design

– Single-Dose IV administration – 1:1:8 ratio for ZFN1:ZFN2:hIDUA donor – Co-administration of three AAV vectors on Day 1

  • Pharmacology/Toxicology studies

– Completed Studies

 Proof-of-concept studies in wildtype and MPS I mice (prevention model)

– In-Progress Studies

 4-month hybrid pharmacology and toxicology study in MPS I mice  GLP 6-month PD, BD and toxicity study of AAV2/6 vectors in C57BL/6 mice  A 90-day pilot study to evaluate pharmacology, biodistribution and potential toxicity of AAV2/6 vectors in cynomolgus monkeys

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Evaluation of SB-318 Specificity

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  • ZFN candidate specificity was evaluated by monitoring off-target modification at

sites identified through

– SELEX-guided bioinformatics analysis No off-target modification observed at the Top 80 predicted off-target sites in human transformed and primary hepatocytes – Unbiased genome-wide off-target assessment via oligo integration analysis Only one off-target site (SMCHD1) among all candidate sites with more than 5 integration events has been confirmed in human transformed and primary hepatocytes

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Oligo Capture Analysis Overview

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Off-Target Site Identified Smchd1

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  • Off-target site in human SMCHD1

gene was tested by dose titration experiment in human hepatocytes

  • There is a clear dose relationship

between albumin on-target and SMCHD1 off-target activity

  • Off-target activity is about 2 logs

lower than on-target activity

  • There is no detectable off-target

activity below 10-20% on-target activity

  • Levels of on-target modification in the

clinical setting are predicted to be <10% at albumin

3e3 1e4 3e4 1e5 3e5 1e6 1e4 1e5 mock 0.0

Gene modification at hALB locus

40% 30% 20% 10% Expected clinical range

SB-FIX ZFNs (SBS47171, SBS47898) GFP MOI AAV2/6

50%

% indels

3e3 1e4 3e4 1e5 3e5 1e6 1e4 1e5 mock 0.0

Gene modification at hSMCHD1 locus

2.0% 1.5% 1.0% 0.5%

SB-FIX ZFNs (SBS47171, SBS47898) GFP MOI AAV2/6

% indels

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SMCHD1 is a Weak Off-Target Site in Non-Human Primate Cells in vitro and in vivo

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A) SMCHD1 off-target site is completely conserved between human and NHP B) In vitro NHP surrogate reagents can cut SMCHD1 in a dose-dependent manner, similar to human SB-318 reagents. Dose titration experiments in rhesus monkey hepatocytes show that only at on-target activity of >10% very low levels of SMCHD1 (<0.02%) modification are detectable C) In vivo day 90 samples from an NHP study using SB-318 surrogate reagents show no detectable off-target activity at SMCHD1 at on-target activities of up to 2.1%. In other studies there was no detectable off-target activity at Smchd1 despite

  • n-target activities of up to 7.4% or 8.7%
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SMCHD1 Gene Function

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  • Structural maintenance of chromosomes flexible hinge domain containing 1 (SMCHD1)
  • Mouse model demonstrated that SMCHD1 is necessary for embryonic development in
  • females. Homozygous male k.o. are initially normal, about half die early (unknown),

the other half has normal lifespan/health > No phenotypes associated with liver were reported; > ZFN expression is restricted to liver through use of a hepatocyte-specific promoter; > Little to no off-target activity seen at on-target levels that model therapeutic setting; > Low levels of SMCHD1 modification should not affect liver cells given they are polyploidy

  • SMCHD1 has role in DNA damage signalling

> We have not observed any increase in DNA Damage Response markers in vitro

  • Germline SMCHD1 mutations are associated with Facioscapulohumeral muscular

dystrophy type 2 (FSHD2) > This disease is caused by muscle cell-specific misregulation of DUX4 transcript; > ZFN expression is restricted to liver through use of a hepatocyte-specific promoter; > No ZFN activity has been observed in tissues other than the liver

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In vitro Evaluation of SB-318 in HepG2 cells

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In vitro Evaluation of SB-318 in HepG2 cells hIDUA protein level and Enzymatic Activity

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HepG2 cells clone 21 clone 25 clone 30

50 100 150 200 250 300

SB-318 hALB ZFNs + hIDUA donor

SB-318 treated HepG2 pools

hIDUA (ng/mL) HepG2 cells clone 21 clone 25 clone 30

50 100 150 200 250 300 350 400 450 500 550 600

SB-318 hALB ZFNs + hIDUA donor

SB-318 treated HepG2 pools

IDUA (nmol/hr/mL)

hIDUA ELISA IDUA Enzymatic Activity

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In vitro Evaluation of SB-318 in HepG2 cells hIDUA protein level and Enzymatic Activity

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HepG2 cells clone 21 clone 25 clone 30

50 100 150 200 250 300

SB-318 hALB ZFNs + hIDUA donor

SB-318 treated HepG2 pools

hIDUA (ng/mL) HepG2 cells clone 21 clone 25 clone 30

50 100 150 200 250 300 350 400 450 500 550 600

SB-318 hALB ZFNs + hIDUA donor

SB-318 treated HepG2 pools

IDUA (nmol/hr/mL)

hIDUA ELISA IDUA Enzymatic Activity

Donor integration in allele 1: Genotyping at allele 2:

HDR NHEJ HDR 3bp 56bp 10bp

  • Del. Ins. Del.
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In vitro Evaluation of SB-318 in HepG2 cells mRNA Analysis at Albumin Locus of HepG2 Subclones

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Donor integration in allele 1: Genotyping at allele 2:

HDR NHEJ HDR 3bp 56bp 10bp

  • Del. Ins. Del.
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In vitro Evaluation of SB-318 in HepG2 cells mRNA Analysis at Albumin Locus of HepG2 Subclones

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Summary of Preclinical Studies

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  • SB-318 ZFNs are highly sequence-specific chimeric nucleases
  • Off-target activity was assessed by unbiased and biased genome-wide assays
  • SMCHD1 was the only off-target locus detected by unbiased oligo capture

assay

  • Off-target activity at the SMCHD1 locus is dose dependent and ~2 logs lower

than on-target activity in vitro and in vivo (NHP).

  • No anchorage-independent cell growth observed after SB-318 treatment in

GLP soft agar transformation assay

  • Studies in clonal HepG2 cell lines with integrated hIDUA donor showed robust

transgene expression independent of integration mechanism

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AAV Mediated Delivery of ZFNs and hIDUA cDNA in Wildtype and MPS I mice

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Study analysis a) Genotyping at albumin locus (not shown) b) Enzymatic activity of hIDUA protein in liver, plasma and secondary tissues c) Urinary and tissue GAG analysis

  • 4-week Proof of concept study in wildtype mice
  • 60-day therapeutic MPS I model study in 4-5 month
  • ld MPS I mice
  • 120-day preventative MPS I model study in 1-2 month
  • ld MPS I mice
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AAV Mediated Delivery of ZFNs and hIDUA cDNA results in Supraphysiological Levels of hIDUA activity in Wildtype mice

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Supraphysiological levels of hIDUA activity detected in liver (primary tissue), plasma and secondary tissues like spleen IDUA activity

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Supraphysiological levels of hIDUA activity detected in liver (primary tissue), plasma and secondary tissues (spleen, kidney and lung) of MPS I mice IDUA activity

AAV Mediated Delivery of ZFNs and hIDUA cDNA Results in Correction of hIDUA Activity in 4-5 month old MPS I Mice

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Significant reduction of urinary and tissue GAG levels in MPS I mice after day 21/60

AAV Mediated Delivery of ZFNs and hIDUA cDNA Corrects GAG Accumulation in 1-2 month old MPS I Mice

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  • SB-318 ZFNs are highly sequence-specific chimeric nucleases
  • Off-target activity was assessed by unbiased and biased genome-wide assays
  • SMCHD1 was the only off-target locus detected by unbiased oligo capture

assay

  • Off-target activity at the SMCHD1 locus is dose dependent and ~2 logs lower

than on-target activity in vitro and in vivo

  • No anchorage-independent cell growth observed after SB-318 treatment in

GLP soft agar transformation assay

  • Studies in clonal HepG2 cell lines with integrated hIDUA donor showed robust

transgene expression independent of integration mechanism

  • Proof-of-Concept demonstrated in wild-type and MPS I mice

Summary of Preclinical Studies

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Agenda

  • MPS I Clinical Background
  • Preclinical Overview

– ZFN technology and the albumin “safe harbor” locus approach – SB-318 IND-enabling nonclinical safety evaluation program – In vitro Evaluation of SB-318 in HepG2 cells

  • Clinical Protocol

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Phase 1 SB-318 MPS I Study - Overview

  • A Phase I, Multicenter, Open-label, Single-dose, Dose Ranging

Study to Assess the Safety and Tolerability of SB-318, a rAAV2/6- based Gene Therapy in Subjects with Mucopolysaccharidosis I (MPS I)

  • Multicenter, open-label, single dose, dose ranging study
  • Investigational Agent – SB-318 is a combination of three AAV2/6

vectors encoding

  • SB-47171: Left side-zinc finger nuclease vector (ZFN1)
  • SB-47898: Right-side zinc finger nuclease vector (ZFN2)
  • SB-IDUA: huIDUA donor vector
  • Number of subjects: 9 subjects; 2 subjects/cohort with expansion to

5 at the third cohort

  • Study Duration: Three years
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Phase 1 SB-318 MPS I Study - Overview

  • Objectives
  • Primary: Safety and tolerability of SB-318
  • Secondary: Assess Immune response to AAV2/6
  • Exploratory

– Change from baseline in the following assessments

  • 1. Liver biopsy for measurement of IDUA activity and GAGs at baseline, 6

months and one year

  • 2. Leukocyte IDUA activity
  • 3. Urine GAG/creatinine ratio (µg/mg)
  • 4. Forced vital capacity (percent of predicted normal)
  • 5. Six-Minute Walk Test (6MWT)
  • 6. Joint ROM
  • 7. Liver and spleen volume
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Phase 1 SB-318 MPS I Study - Overview

  • Inclusion Criteria

1. Written informed consent 2. Male or female >18 yrs of age 3. Clinical diagnosis of attenuated MPS I deficiency (Hurler-Scheie, Scheie, or Hurlers s/p BMT) confirmed by

a) IDUA gene sequencing, or b) receiving treatment with laronidase, , or c) a history

  • f an elevated urinary GAG/crt ratio, or d) documentation of tissue, or e) plasma IDUA

< 10% of the normal range.

4. Forced vital capacity (FVC) of <80% of predicted 5. No history of infusion reactions or anaphylaxis to laronidase 6. Negative pregnancy test (female of childbearing potential) 7. Sexually mature subjects must agree to use barrier contraceptive as follows: females for three months; males, until at least 3 consecutive semen samples after SB-318 administration are negative for AAV 2/6 8. No contraindication to the use of corticosteroids for immunosuppression

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Phase 1 SB-318 MPS I Study - Overview

  • Exclusion Criteria
  • 1. Neutralizing antibodies to AAV 2/6 at titers >1:4
  • 2. Clinically significant organic disease (unless secondary to MPS I) such as cardiovascular,

hepatic, pulmonary, neurologic, or renal disease

  • 3. Serious intercurrent illness
  • 4. Active hepatitis B (Hepatitis B DNA, or HBsAg positive) or hepatitis C (HCV RNA viral load).

To be considered negative, a history of sustained virologic response (viral assays in two sample collected at least six months apart must be negative)

  • 5. Abnormal baseline liver function tests (ALT or AST >2x upper limit of normal (ULN), albumin

<3.5 g/dL, total bilirubin > 2x ULN,

  • 6. History of liver disease such as hepatitis, steatosis, cholangitis, cirrhosis, biliary disease, etc.

(Gilbert’s syndrome is excluded)

  • 7. Current treatment with systemic (iv or oral) immunomodulatory agent or steroid use

(topical treatment is allowed, e.g., asthma or eczema)

  • 8. Participation in prior investigational drug or medical device study within the previous 6

months

  • 9. Prior treatment with a gene therapy product
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Phase 1 SB-318 MPS I Study - Overview

  • Dose of Study Drugs
  • Dose Escalation

1. Dose escalation cannot occur until at least 4 weeks after the last subject in the preceding cohort has been dosed, and safety data from the prior cohort has been reviewed by the Safety Monitoring Committee 2. Three additional subjects will be enrolled and treated in a cohort if one subject within a cohort develops a dose limiting toxicity (DLT) defined as a two Grade 2 AE in the same

  • rgan system that dose not resolve in 14 days of treatment, and any grade 3,or 4

ZFN 1 (vg/kg) ZFN 2 (vg/kg) cDNA Donor (vg/kg) Total rAAV Dose (vg/kg) 5.00E+11 5.00E+11 4.00E+12 5.00E+12 1.00E+12 1.00E+12 8.00E+12 1.00E+13 5.00E+12 5.00E+12 4.00E+13 5.00E+13

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Phase 1 SB-318 MPS I Study Schema

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Screen Infusion and Safety Evaluations - 12 months

BL Day 0 -1 1 2 3 4 5 6 7 8 9 10 11 12 16 20 24 28 32 36 40 44 48 52 Week

Hospitalization for SB-318 Infusion Follow Up 36 months Study Period ~ 15 months

M18, 24, 36, 48

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Phase 1 SB-318 MPS I Study - Overview

  • Safety Monitoring and Mitigation Plan

– Liver function (AST, ALT, bilirubin, alkaline phosphatase, albumin and PT) will be monitored three times weekly during the first 12 weeks after SB-318 infusion and then monthly thereafter

  • Key Potential Anticipated Risks

– Transaminitis due to cell-mediated immunity to capsid and/or AAV gene product. Steroids (oral or intravenous) may be administered per PI – Reduction in albumin synthesis. The fraction given of transduced cells with albumin locus disruption (<1%), and has not been

  • bserved in preclinical rodent and NHP animal studies