SB-525, A NOVEL GENE THERAPY FOR TREATMENT OF HEMOPHILIA A Kathleen - - PowerPoint PPT Presentation

SB-525, A NOVEL GENE THERAPY FOR TREATMENT OF HEMOPHILIA A

Kathleen Meyer MPH, PhD, DABT Sangamo Therapeutics NorCal SOT Meeting October 24, 2019

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We are committed to translating ground-breaking science into genomic medicines that transform patients’ lives

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Our capabilities allow us to design therapeutic approaches targeting the underlying genetic causes of disease

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Gene Therapy

Gene therapy provides tractable, valuable near-term

• pportunities

Our capabilities allow us to design therapeutic approaches targeting the underlying genetic causes of disease

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Gene Therapy Gene-Edited Cell Therapy

Gene therapy provides tractable, valuable near-term

• pportunities

Continue to advance ex vivo editing to create cell therapies

Ex Vivo

Our capabilities allow us to design therapeutic approaches targeting the underlying genetic causes of disease

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Genome Editing Gene Regulation Gene Therapy Gene-Edited Cell Therapy In Vivo

Gene therapy provides tractable, valuable near-term

• pportunities

Continue to advance ex vivo editing to create cell therapies Sustain momentum toward the long-term goal with in vivo gene editing and gene regulation

Ex Vivo

Sangamo’s genomic medicines encompass a breadth of technical approaches and diverse pipeline assets

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SB-525: Hemophilia A ST-920: Fabry disease Undisclosed targets ST-400: Beta thalassemia BIVV003: Sickle cell disease TX200: Solid organ transplant KITE-037: Allo-CD19 CAR-T Undisclosed targets SB-913: MPS II SB-318: MPS I SB-FIX: Hemophilia B Undisclosed targets

Genome Editing Gene Regulation

Tauopathies C9ORF72-linked ALS/FTLD Huntington’s disease Undisclosed targets

Gene Therapy Gene-Edited Cell Therapy In Vivo Ex Vivo

Therapeutic Area Research Preclinical Phase I/II Phase III Collaborator Gene Therapy

Hemophilia A (SB-525) Fabry disease (ST-920)

Ex Vivo Gene-Edited Cell Therapy

Hemoglobinopathies (ST-400, BIVV003) Solid organ transplant CAR-Treg (TX200) Allogeneic anti-CD19 CAR-T (KITE-037)

In Vivo Genome Editing

MPS II (SB-913) MPS I (SB-318) Hemophilia B (SB-FIX)

In Vivo Gene Regulation

Tauopathies ALS/FTLD - C9ORF72 Huntington’s Disease

Robust pipeline of genomic medicines in clinical and preclinical stages of development

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• Deficiency in FVIII clotting factor
• Bleeding disorder occurring most often inside joints and

muscles

• 70% of patients inherit Hemophilia A and 30%

develop spontaneous genetic mutation

• Approximate incidence (CDC) 1 in 5,000 male births
• 16,000 patients in US
• 108,000 patients identified globally (WFH)
• Average annual Hemophilia A treatment cost in

developed work $150 – 300K Hemophilia A: chronic, disabling, painful and destructive disease

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.

FVIII and the coagulation cascade

Therapeutic Value Evolution of Products

Evolution of hemophilia treatment

Recombinant Era

Improved Safety

► Eliminated potential for transmission of blood borne pathogens Recombinant Clotting Factors FVIII, FIX, FVIIa (1990s) Plasma-Derived Clotting Factors (1969) ► Widespread viral contamination ► Biosimilars ► Humanized ► Prolonged half-life (FVIII/FIX)

EHL clotting factors (2014 - )

► Gene therapy ► Novel agents

Investigational therapies (2015 – )

• Single gene disorder

– Clear cause and effect relationship

• Replacement administration is

demanding

– Must be given 3x weekly iv

• Wide therapeutic window

– Low levels will improve outcome – High levels welcome (up to a point)

• Efficacy easy to assess

– Clinical – Laboratory

Why gene therapy for hemophilia?

SB-525

• Recombinant adeno-associated virus (AAV) has been used

extensively for nearly 20 years as a gene therapy vector in preclinical and clinical studies

• Efficient transduction and long term, stable transgene expression in

non-dividing cells such as liver, neurons and muscle

• Non-pathogenic, replication-deficient
• High degree of stability which allows for rigorous methods of

vector purification

• AAV vectors carrying capacity is small (~4.7 kb of DNA)
• Composed of inverted terminal repeats (ITRs) flanking transgene

construct

• SB-525 utilizes AAV2 ITRs and AAV6 capsid proteins

SB-525 for the treatment of adults with hemophilia A

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AAV2/6

• hF8 is not an ideal gene for AAV

– Constrained by hF8 gene size

• Optimal AAV transgene size is ~4.7 kg; full length hF8 is ~7kb
• AAV dose required to achieve therapeutic hFVIII levels
• Shorter coding sequence for hF8
• Optimized B-domain deleted sequence (BDD)
• Optimized liver-specific promoter modules to drive hF8 expression
• Improved virus yields

What is optimal for rAAV human F8 cDNA?

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Optimization of AAV hF8 cDNA required multi-factorial modifications

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PolyA hF8 B-domain deleted (BDD) ITR ITR

Liver-specific promoter

Promoter module modifications

• Assembled different permutations of liver-

specific promoter elements

• A systematic mutational design approach

was used to improve regions of the promoter module

Transgene modifications

• Optimized the F8 cassette

Other modifications

• Identified minimal synthetic polyA
• Removed unnecessary nucleic acids to

reduce size

• Optimized sequences outside transgene

hFVIII protein has the same amino acid sequence as biologics currently in clinic

SB-525 liver directed AAV6 hF8 cDNA gene therapy for hemophilia A

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P liver- specific promoter TG therapeutic gene (F8)

Transgene packaged into AAV vectors Therapeutic delivered by a single infusion

Liver produces and secretes therapeutic hFVIII protein

 

AAV vectors Liver Cell DNA Promoter Therapeutic Gene (hF8) Nucleus Liver Cell Transgene is expressed from the liver, but remains separate from the cell’s DNA

P TG

transgene Transgene packaged into AAV vectors AAV is delivered by a single infusion AAV traffics to liver to deliver transgene into nucleus of liver cells

• Establishment of biological plausibility
• Identification of biologically active dose levels
• Selection of potential starting dose level, dose-escalation schedule and dosing

regimen for clinical studies

• Establishment of feasibility and reasonable safety of product’s proposed

clinical route of administration

• Support of patient eligibility criteria
• Identification of physiological parameters that can guide clinical monitoring
• Identification of potential public health risks

Objective of the nonclinical program

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• In vitro studies in primary human hepatocytes showing hFVIII production
• 3-month pharmacology study in hemophilia A mice
• 2-month pharmacology and toxicity study with highly related variant of

SB-525

• 3-month GLP pharmacology, biodistribution and toxicity study in mice
• 2-month pharmacology, biodistribution and toxicity study in cynomolgus

monkeys Nonclinical studies supporting First-in-Human study

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Gene therapy FDA and EMA guidance documents

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• Hemophilia A mouse model to demonstrate SB-525

pharmacodynamic activity

• SB-525 IV dose of 7.2E+12 vg/kg
• Hemophilia A R593C mice are tolerized to hFVIII as they

contain a hF8-R593C transgene under control of a mouse albumin promoter

• Human FVIII-R593C mutation is frequently found in Hemophilia

A patients; in mice produces no detectable hFVIII protein

• Thought to be rapidly degraded in mice, with peptide fragments

presented to the immune system

• Mice also contain a knockout of the mouse F8 gene and are

deficient for endogenous mouse FVIII protein

SB-525 pharmacodynamic activity in hemophilia A mice

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7 Test article injection 14 21 28 days 3 months Plasma collection schedule

Endpoint

• Chromogenic assay for

hFVIII activity

• Tail vein transection

(TVT) for hemostasis

Hemophilia A mouse model shows SB-525 functional impact

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TVT method based on Johansen et al., Haemophilia, 1-7, 2016

F o rm u la tio n S B -5 2 5 1 0 2 0 3 0 4 0 5 0

p < 0 .0 0 0 1 T o ta l B le e d in g T im e (m in )

n o r m a l b le e d in g tim e

Bleed Time Tail Vein Transection (TVT)

F o rm u la tio n S B -5 2 5 2 0 0 4 0 0 6 0 0

h F V III (P e rc e n t N o rm a l) 458.1

hFVIII Activity

Activity determined by Chromogenic Activity Assay

• 2-month study in cynomolgus monkeys
• SB-525 IV doses 2E+11 vg/kg to 6E+12

vg/kg

• Pharmacodynamic endpoints
• Biodistribution endpoints
• Safety endpoints

SB-525 pharmacology and toxicology NHP study design

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7 Test article injection 14 21 28 days 56 days Plasma collection schedule

Endpoints

• ELISA for hFVIII levels
• qRT-PCR for hF8 mRNA
• Biodistribution
• Safety assessment

Immunosuppression (IS) regiment of rituximab and steroids; early and late IS regiment

SB-525 NHP data – h8 mRNA expression restricted to liver

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hF8 mRNA (qRT-PCR)

L iv e r H e a rt K id n e y B ra in (F C ) B ra in (C e r) S p le e n T e s te s L u n g 5 1 0 1 5 2 0 2 5

R e la tiv e N o rm a liz e d E x p re s s io n

• Restricted hF8 mRNA liver expression;

identical results observed in mice

6 E + 1 1 9 E + 1 1 2 E + 1 2 6 E + 1 2 0 .1 1 1 0 1 0 0

D o s e (v g /k g ) R e la tiv e N o rm a liz e d E x p re s s io n L e ft L a te ra l L iv e r L o b e

6 E + 1 1 9 E + 1 1 2 E + 1 2 6 E + 1 2 0 .1 1 1 0 1 0 0

D o s e (v g /k g ) R e la tiv e N o rm a liz e d E x p re s s io n R ig h t L a te ra l L iv e r L o b e

6 E + 1 1 9 E + 1 1 2 E + 1 2 6 E + 1 2 0 .1 1 1 0 1 0 0

D o s e (v g /k g ) R e la tiv e N o rm a liz e d E x p re s s io n L e ft M e d ia l L iv e r L o b e

6 E + 1 1 9 E + 1 1 2 E + 1 2 6 E + 1 2 0 .1 1 1 0 1 0 0

D o s e (v g /k g ) R e la tiv e N o rm a liz e d E x p re s s io n R ig h t M e d ia l L iv e r L o b e

6 E + 1 1 9 E + 1 1 2 E + 1 2 6 E + 1 2 0 .1 1 1 0 1 0 0

D o s e (v g /k g ) R e la tiv e N o rm a liz e d E x p re s s io n C a u d a te L iv e r L o b e

• Uniform hF8 mRNA distribution across liver

lobes

SB-525 dose response supports clinical dose selection

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2 E + 1 1 6 E + 1 1 9 E + 1 1 2 E + 1 2 6 E + 1 2 1 1 0 1 0 0 1 0 0 0

T o ta l D o s e (v g /k g ) h F V III (P e rc e n t N o rm a l)

56.4 227.9 6.4 11.7 3.9

Therapeutic levels of hFVIII (> 5% of normal) support starting clinical doses in the E11 vg/kg range

NHP Data – kinetics of hFVIII expression, peak levels Day 7-14

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Plasma hFVIII Levels

G ro u p 5 6 E + 1 2 v g /k g

• 2 0

2 0 4 0 6 0

5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0

D a y s P o s t D o s in g h F V III (P erce n t N o rm al)

A n im a l 2 2 h F V III A n im a l 2 4 h F V III A n im a l 2 6 h F V III

G ro u p 4 2 E + 1 2 v g /k g

• 2 0

2 0 4 0 6 0

2 0 4 0 6 0 8 0

D a y s P o s t D o s in g h F V III (P erce n t N o rm al)

A n im a l 1 8 h F V III A n im a l 2 0 h F V III A n im a l 4 2 h F V III

SB-525 safety - summary of liver biodistribution and histopathology

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Strain/ Species Highest AAV Dose (vg/kg) Duration (months) Immuno- suppression ALT/AST Levels Biodistribution/ Shedding End of Study Liver Histopathology End of Study

C57BL/6 / Mouse GLP Study 2E+13 1, 2, 3 No Normal

• VGs highly liver-trophic, none detected in

brain/testes

• No VGs detected in urine, saliva, feces,

semen No signs of hepatocellular hyperplasia, tumors or toxicity Hemophilia A (hFVIII-R593C) / Mouse 2E+13 2 No Not Done

• Not Done

No signs of hepatocellular hyperplasia, tumors or toxicity Cynomolgus Monkey (highly related variant) 6E+12 8-9 Yes Normal

• VGs highly liver-trophic, none detected in

brain/testes No signs of hepatocellular hyperplasia, tumors or toxicity Cynomolgus Monkey 6E+12 3 Yes Normal

• VGs highly liver-trophic, none detected in

brain/testes

• No VGs detected in urine, saliva, feces in

high dose group after 4 days No signs of hepatocellular hyperplasia, tumors or toxicity

SB-525, gene therapy for hemophilia A

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Goals

• Orphan Drug
• Fast Track
• RMAT

IND open

• Orphan Medicinal Product

Patient safety FVIII activity Reduction of bleeding events Reduction of factor replacement use Phase I/II Open Label Study (ALTA)

Dose Escalation Complete Cohort 3 Cohort 1 Cohort 2 Cohort 4

• Enrollment complete
• Updated results presented at ISTH

Next steps Ongoing Phase I/II Study

9e11 vg/kg 2e12 vg/kg 1e13 vg/kg 3e13 vg/kg

(Patients did not receive prophylactic steroids)

• Present follow-up patient data in 4Q 2019
• Complete transfer of manufacturing to Pfizer
• Regulatory discussions underway for Phase III

Factor VIII activity: chromogenic assay

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Konkle BA et al. ISTH 2019 Melbourne, AU, 6 July 2019

Study Week

10 20 30 40 50 60 10 20 30 40 50 60

Study Week

250 200 150 100 50 100 10 1

Logarithmic Linear

Subject 4 (2e12 vg/kg) Subject 5 (1e13 vg/kg) Subject 6 (1e13 vg/kg) Subject 7 (3e13 vg/kg) Subject 8 (3e13 vg/kg) Subject 9 (3e13 vg/kg) Subject 10 (3e13 vg/kg)

Moderate (1-5%) Normal (50-170%) Mild (6-49%)

Factor VIII Activity (IU/dL)

* Subsequent to the data cut used for the ISTH presentation, Subject 9 attained normal levels at week 7

* *

Factor VIII activity: chromogenic, Cohort 4 (3e13 vg/kg)

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Factor VIII Activity (IU/dL)

100 10 Konkle BA et al. ISTH 2019 Melbourne, AU, 6 July 2019

Logarithmic

5 10 15 20 25

Study Week

Subject 7 (week 24) Subject 8 (week 19) Subject 9 (week 6) Subject 10 (week 4)

Normal (50-170%) Mild (6-49%)

*

* Subsequent to the data cut used for the ISTH presentation, Subject 9 attained normal levels at week 7

Spontaneous bleeding episodes

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Dose Cohort (dose vg/kg)

1 (9e11) 1 93 7 1 (9e11) 2 83 5 2 (2e12) 3 73 8 2 (2e12) 4 66 5 3 (1e13) 5 50 5 3 (1e13) 6 41 4 (3e13) 7 24 4 (3e13) 8 18 4 (3e13) 9 5 4 (3e13) 10 2 n/a*

Subject Follow-Up (weeks) Bleeding Episodes ≥3 weeks Post Treatment

Konkle BA et al. ISTH 2019 Melbourne, AU, 6 July 2019 Data cut-off date: 30 MAY 2019 *n/a: < 3 weeks of follow-up at time of data cut

Factor VIII replacement usage

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Dose Cohort (dose vg/kg)

1 (9e11) 1 93 2/Week 115 1 (9e11) 2 83 2/Week 26 2 (2e12) 3 73 2/Week 13 2 (2e12) 4 66 3/Week 9 3 (1e13) 5 50 Every Other Day 11 3 (1e13) 6 41 Every Other Day 4 (3e13) 7 24 Every 4 Days 4 (3e13) 8 18 Every Other Day 1* 4 (3e13) 9 5 Every 3 Days 4 (3e13) 10 2 Every 3 Days n/a§

Subject Follow-Up (weeks) Factor VIII Prophylactic Regimen Prior to Dosing Factor VIII Infusions ≥ 3 weeks Following SB-525 Treatment

*Prophylactic coverage stopped 3 weeks and 2 days after SB-525 administration, §n/a: < 3 weeks of follow-up at time of data cut Konkle BA et al. ISTH 2019 Melbourne, AU, 6 July 2019 Data cut-off date: 30 MAY 2019

Treatment-related adverse event (TRAE) summary

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N= Total number of subjects in each treatment group, n= number of subjects in each system organ class (SOC), [T]= total number of treatment-related adverse events. *All 3 events were reported as Grade 2 ** Grade 3 event reported.

MedDRA Preferred Term

Any treatment-related event 2 (100) [4] 3 (75) [8] 5 (50) [12] Alanine aminotransferase increased 2 (100) [3] 1 (25) [1] 3 (30) [4] Pyrexia 3 (75) [3]* 3 (30) [3] Aspartate aminotransferase increased 1 (50) [1] 1 (10) [1] Fatigue 1 (25) [1] 1 (10) [1] Hypotension 1 (25) [1]** 1 (10) [1] Myalgia 1 (25) [1] 1 (10) [1] Tachycardia 1 (25) [1] 1 (10) [1]

Cohort 1

9e11 vg/kg (N=2) n(%)[T]

Cohort 2

2e12 vg/kg (N=2) n(%)[T]

Cohort 3

1e13 vg/kg (N=2) n(%)[T]

Cohort 4

3e13 vg/kg (N=4) n(%)[T]

Overall

(N=10) n(%)[T]

Konkle BA et al. ISTH 2019 Melbourne, AU, 6 July 2019 Data cut-off date: 30 MAY 2019

• Treatment-related SAEs of hypotension (grade 3) and fever (grade 2) in one Cohort 4

subject occurred 6 hrs following SB-525 infusion. Fully resolved with treatment within 24 hrs

• Based on the temporal association, assessed as related to study treatment
• No similar hypotension observed in subsequent 3 subjects dosed
• In the 3e13 vg/kg cohort two subjects experienced a transient grade 1 alanine

aminotransferase elevation (>1.5 x baseline) managed with a tapering course of oral

• steroids. Neither resulted in a loss of FVIII activity levels

Safety summary

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Konkle BA et al. ISTH 2019 Melbourne, AU, 6 July 2019 Data cut-off date: 30 MAY 2019

Acknowledgements

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• Liching Cao
• Mubarack Muthalif
• Judy Greengard
• Annemarie Ledeboer
• Lisa King
• Stephen Ballaron
• Daniel Richards
• Melanie Butler
• Carolyn Gasper
• Kathy Meyer
• Dale Ando
• Didier Rouy
• Nathalie Dubois-Stringfellow
• Our clinical trial subjects,

families and physicians

• Brigit Riley
• Mike Holmes
• Jeff Boonsripisal
• Derek Liu
• Rainier Amora
• Lei Zhang
• Jianbin Wang
• Susan Abrahamson
• Richard Surosky
• Alicia Goodwin
• Andrea Kang
• Tim Gabriele
• Hung Tran
• Jennifer Huang
• David Lillicrap
• Christine Hough
• Dominique Cartier
• Kate Nesbitt
• Courtney Dwyer
• Kassandra Herbert