Immune Tolerance Induction in Enzyme

Replacement Therapy for Lysosomal

Storage Diseases: Optimizing Therapeutic

Outcome with Preventive Strategies

Amy S. Rosenberg, M.D.

Director, Division of Therapeutic Proteins,

CDER, FDA

1

Risk of Immune Response Across the Spectrum of Lysosomal

Storage Diseases: What do we Know about the Consequences?

No basis for

probabilities

Knowledge

about likelihoods

Strong basis

for

probabilities

Knowledge about Consequences

Consequences

well-defined

Consequences

poorly-defined

Risk (I)Ambiguity

(III)

Ignorance

(IV)

Uncertainty

(II)

Incertitude

(modified from Stirling and Ghee 2002)2

Pompe Disease Fabry Disease, MPS1

Acting on Immunogenicity Risk Assessment

• Severity of consequences of the immune response to therapeutic

proteins determines course of action:

– when consequences are life threatening, tolerance induction is indicated

– when life threatening immune responses can be predicted based on

genetic mutation or CRIM status, prophylactic tolerance protocols are

indicated: incur less risk than either poorly treated lysosomal storage

disease or more prolonged therapeutic immune suppressive tolerance

induction regimens

– tolerance induction should be strongly considered when a

preponderance of evidence indicates that the immune response is

diminishing the efficacy of effective (but not necessarily life saving)

therapeutics

– risks associated with tolerance regimens and impact of tolerance

regimen on underlying disease should be considered

3

Consequences of the Immune Response to Protein Therapeutics for

which Immune Tolerance Induction is Indicated

• Abrogation of the efficacy of life saving therapeutics by neutralizing antibodies or sustained high titer antibodies

– Coagulation and Enzyme Replacement Therapies in CRIM negative patients

• Anaphylaxis to life saving therapeutic proteins

– Highly efficacious proteins of non-human origin

– ERT, Factor IX in hemophilia B

• Neutralization of endogenous factor with unique function resulting in cellular or critical factor deficiency syndrome

– Thrombopoietin: thrombocytopenia

– Erythropoietin: pure red cell aplasia

– GM-CSF: acquired pulmonary alveolar proteinosis4

Antibody May Block ERT Target Cell Entry and Catalytic Activity

or Facilitate Enzyme Uptake in Nontarget Cells

EE

UD

Lysosome

Processedenzyme

CCV

Endosome

E UD

5

E

IC degraded?

Fuse with MHC

class II pathway

E

E

E UDProcessed

enzyme

E

Pompe Disease

• Infantile Pompe disease (IPD) – Lysosomal Storage Disease (LSD) resulting from a deficiency of lysosomal acid alpha glucosidase (GAA).

• Can be a rapidly fatal disease primarily affecting cardiac and skeletal muscle: death within the first 2 years of life from cardiac and respiratory failure.

• Because of rapid progression, efficacy of Enzyme Replacement Therapy (ERT) and effects of immune responses to ERT are clear (heart failure, weakness, requirement for invasive ventilation), as compared to slowly progressive LSDs with more distant endpoints

• Recombinant human GAA (rhGAA, Myozyme and Lumizyme®) is currently the only available therapeutic. No bypass or salvage therapies 6

CRIM Negative and A Subset of CRIM Positive Patients Mount

High Titer/Sustained Antibody Responses to ERT(Kishnani PS et al 2011)

High Titer Antibody Response, not CRIM Status Per Se, Confers Negative

Clinical Outcome in ERT-Treated Patients with Pompe Disease

(Kishnani PS et al 2011)8

High Titer CRIM+

Low Titer CRIM+

CRIM–

Clinical Scenario 1: Treatment Naïve Patient(P. Kishnani ITN, May 2007)

• Birth weight 7lb8oz, cleft lip and

palate.

• At age 5 weeks:respiratory

symptoms, cardiomegaly,

hypertrophic cardiomyopathy

166g/m2, SVT.

• Diagnosis of Pompe made

based on absent GAA,

homozygous for R854stop,

CRIM negative on skin western

• Need for immediate treatment

due to cardiac and respiratory

failure

Potential Approaches to Immune Tolerance Induction

• Ideal: Approaches that are highly antigen specific with consequent preservation of global immunity

– Protein therapeutics: linked tolerance via known tolerogens, e.g., Fc moieties; tolerance (e.g., Factor VIII) protocols based on dose escalation and frequency

– Cellular therapy: induction/administration of antigen specific regulatory T cells (Tregs); mesenchymal stem cells;

– Gene therapy: some success in patients with hemophilia B; successful in mouse models of Pompe Disease-liver targeting essential

– Oral tolerance

• Antigen specific approaches may be problematic for clinical settings requiring immediate treatment or in clinical settings in which significant end organ damage may occur during a prolonged course of tolerance induction

– Antigen specific approaches may take weeks-months for induction of durableimmune tolerance

– End organ damage may potentially progress/become irreversible during prolonged tolerance induction protocols

– In situations in which clinical treatment and thus, tolerance induction must begin urgently because of deteriorating clinical status, therapeutic options are more limited

10

Tolerance Induction Strategies: Targeting Components of the

Adaptive Immune Response

CD20

BCR

Methotrexate

Short lived

Plasma cell

Targeted therapeutic

protein: tolerogenic DCs

DC

Peptide

Cytokines

MHCII TCR

CD20

Memory B cell

AntibodiesHelper T cell

B cellCD20?

Antibodies

Long lived

Plasma cell

Rituximab

Bortezomib

Non-depleting

CD4mAb

11

Rituximab IV (375 mg/m2; if BSA<0.5 m2, 12.5 mg/kg)

Methotrexate SC (0.4 mg/kg)

IVIG (400-500 mg/kg)

Alglucosidase alfa (20 mg/kg every other week)

Wk0 Wk1 Wk2 Wk3 Wk4 Wk5 Wk6

Prophylactic ITI Protocol

Banugaria S et al PlosOne 2013

100

An

ti-r

hG

AA

Ig

G a

ntib

od

y t

ite

r)

0

Weeks on ERT

10 20

10000000

1000000

100000

10000

1000

30 40 50 60 70 80 90 100

CN ERT + ITI* (7)

CN ERT Monotherapy (8)

Efficacy of Prophylactic ITI + ERT

Banugaria SG et al PlosOne 2013

Ventila

tor

Fre

e S

urv

ival

0.00

0

Months

5

1.00

0.75

0.50

0.25

10 15 20 25 30

CN ERT + ITI*

CN ERT Monotherapy

*

Improved Ventilator Free Survival with ITI + ERT

3 on ventilator became ventilator free

Banugaria SG et al PlosOne 2013

Prophylactic Approach to Tolerance Induction

• Limited experience, but excellent safety profile: one case of

infection (bronchitis) which cleared rapidly

• Two patients with titers > 1:6400 required a second course:

decreased titer in one; stable titer in second.

• One patient died of progressive Pompe Disease not related to

tolerance induction

• Recommended protocol for CRIM negative Pompe

Disease at onset of enzyme replacement therapy

• Given the safety profile, should this protocol be recommended for

CRIM positive patients until we can predict those who will mount

high titer?

15

Clinical Scenario 2: High Sustained Antibody Titers(P. Kishnani ITN, May 2007)

• At age 5 weeks:respiratory symptoms, cardiomegaly, hypertrophic cardiomyopathy 166g/m2, SVT.

• Diagnosis of Pompe made based on absent GAA: Homozygous for R854stop; CRIM negative

• First Myozyme (rhGAA) infusion at age 6 weeks. Dosed at 20mg/kg every 2 weeks

• Patient develops high sustained antibody titers and clinically deteriorates: titer >1:25,000 despite treatment with immune suppressive agents

Information received from Children’s Hospitals and Clinics of Minnesota

Requirement for Intensive and Prolonged Immune Suppression to Eliminate

Antibody Response in Patients with High Sustained Antibody Titers(Kishnani PS et al 2012)

900000

1/A

nti-r

hG

AA

Ig

GA

ntib

od

y T

ite

r

Weeks on ERT

800000

700000

600000

500000

400000

300000

200000

100000

00 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230

190

170

150

130

110

90

70

50

210

1:819,200

200.9

95

1:409,600 1:409,600

139

158

105

77.882.5

1:6,4001:12,800

1:51,200

1:102,400

1:204,8001:204,800

60.3

1:102,400

1:204,800

Le

ft V

en

tric

ula

r M

ass In

de

x (

g/m

2)

Rituximab (375 mg/m2IV)

Methotrexate (15 mg/m2SC)

Bortezomib (1.3 mg/m2IV)

IVIG (400-500 mg/kg IV monthly)

Antibodies LVMI

Confirmed CRIM negative

ITI + ERT

Monitor anti-rhGAA IgG antibodies, CD19% and clinical progress

No or low antibodies

(<6,400) and CD19%

recovery at ≥ 5 months

Increasing antibodies

(≥6,400) at two or more time points and

CD19% recovery at ≥ 5 months

Monitor antibodies

and clinical outcome

parameters

Repeat ITI and monitor

antibodies, CD19% and

clinical progress

Increasing Antibodies

(≥6,400) at two or more time

points and CD19% recovery at ≥ 5

months after last ITI

No or low antibodies

(<6,400) and CD19%

recovery at ≥ 5 months

of last ITI

ITI with plasma cell

targeting agent

Diagnosis of Pompe Disease: CRIM negative status determination

††

Kishnani PS et al

PLoS One 2013

Tolerance Induction Indicated when the Consequence of the

Immune Response to Protein Therapeutics is Fatality/Severe

Morbidity

• Neutralizing antibodies or high titer antibodies that neutralize efficacy of life saving therapeutics

– Enzyme and coagulation factor replacement therapies in protein knock out (CRIM negative) phenotype

• Anaphylaxis to life saving therapeutic proteins

– Highly efficacious proteins of non-human origin

– Human proteins in CRIM negative patients: e.g., ERT (rare), Factor IX in hemophilia B

• Neutralization of endogenous factor with unique function resulting in cellular or critical factor deficiency syndrome

– Thrombopoietin: thrombocytopenia

– Erythropoietin: pure red cell aplasia

– GM-CSF: acquired pulmonary alveolar proteinosis 19

Management of Anaphylaxis to Factor IX:

Lessons for IPD

• Avoidance:

– Factor IX bypass therapy; no bypass therapy for Pompe Disease

• Desensitization: not an appropriate strategy for Pompe Disease in absence of bypass therapy

• Tolerance Induction

– New approaches to Tolerance Induction

• Anti-CD20 mAb

• Anti-IgE mAb should be considered for IgE positive patients with anaphylaxis

• Gene therapy

20

Anti-IgE for Treatment of IgE Mediated Anaphylaxis

to a Therapeutic Enzyme(Rohrbach et al J. Inherit Metab Dis 2010)

• Patient with IPD on ERT experienced persistent life-threatening anaphylaxis episodes that were not controlled with corticosteroids, antihistamines, or decreased infusion rate.

– A scratch skin test for Myozyme tested positive

– IgE positive for ERT

• Treatment regimen was optimized by adding omalizumab, a recombinant monoclonal antibody against IgE.

– Patient continued to receive ERT

– Treatment for anaphylaxis weaned with the exception of omalizumab.

– rhGAA specific IgG antibody titers were measured routinely every 4–5 months and were always <1:800 (low).

• Continuation of omalizumab necessary? Did anti-IgEtreatment preclude generation of high titer IgG response?21

What is the Evidence that the Immune Response to ERT

for other Lysosomal Storage Diseases Affects

Safety and Efficacy?

• Clinical manifestations, effect of ERT and effect of immune response

to ERT are very clear in Pompe Disease with loss of motor

milestones and cardiac failure;

• The effects of ERT on clinical manifestations and effect of immune

response to ERT in more slowly progressive LSDs are not clear in

many cases. Clinical endpoints for some are only reached after

many years of disease: e.g., MPS1

• Validated biomarkers that predict clinical efficacy of ERT and reveal

impact of immune response to ERT are lacking for most LSDs

22

Ambiguity (modified from Stirling and Ghee 2002)

No basis for

probabilities

Knowledge

about likelihoods

Some basis

for

probabilities

Knowledge about Consequences

Consequences

well-defined

Consequences

poorly-defined

Risk (I)Ambiguity

(III)

Ignorance

(IV)

Uncertainty

(II)

Incertitude

23

MPS 1

• Deficiency of a-L-iduronidase leading to accumulation of heparan

sulfate and dermatan sulfate glycosaminoglycans in lysosomes

• Spectrum ranging in severity from Hurler’s (severe) to Scheie

(attenuated) with Hurler-Scheie intermediate in spectrum

• Hurler’s presents early (birth-2 years) and rapidly progresses:

mental retardation, dwarfism, coarse facies, dysostosis multiplex

and hepatosplenomegaly; death within a decade if untreated

• Scheie: onset delayed; little or no neuronal involvement

• Treatment

– ERT: a-L-iduronidase (Laronidase)

– Allogeneic BMT

24

CRIM Negative MPS I Patients do not Tolerize

Over Time

• Under 5 Study in Hurler (CRIM negative) patients

– Stronger immune responses

– Some decrease in urinary GAG reduction

– Decline in titers but not tolerant

25

Most CRIM Negative Patients with MPS 1 do not Tolerize Over Time(Genzyme, unpublished)

IgG response to laronidase

1

10

100

1000

10000

100000

1000000

baseline week 4 week 8 week 12 week 16 week 20 week 24 week30 week 34 week 37 week 39 week 51

laronidase treatment in weeks

An

tib

od

y t

itle

s (

log

sc

ale

)

26

Evidence that Antibody Response Affects

Optimal Activity of ERT in MPS I

• Correlation of disease biomarkers with antibody

response in MPS I patients

• Immune tolerance to ERT improves tissue

penetration of enzyme, substrate reduction, and

improved histopathology (with higher treatment

dose) in CRIM negative MPS I dogs

27

Antibodies to Laronidase Associated with Increased Substrate Levels(Wraith JE et al 2007)

1

10

100

1000

10000

100000

1000000

0 10 20 30 40 50 60 70 80 90 100

% Reduction in Urinary GAG

An

tib

od

y T

ite

r (l

og

sc

ale

)

Hig

he

r le

ve

l: >

16

00

Lo

we

r le

ve

l: <

16

00

below median < 63.3 % above median > 63.3 %

200 U/kg, MPS I H100 U/kg, MPS I H28

MPS 1 Dogs Have Robust Antibody Response to a-L-

Iduronidase but can be Tolerized(Kakkis E et al 2004)

30

550

Weeks of rhIDU

An

tib

od

y tite

r

JA

JO

ME

MA

MO

PA

BI

BC

BO

RU

UM

RH

RI

RO

PE

SA

NI

TA

VK

20

500

450

400

350

300

250

200

150

100

50

0

4 6 8 10 12 14 16 18 20 22 24 26 28

CsA+Aza End

29

Improved Target Tissue Penetration, Substrate Reduction and Histopathology in Tolerant MPS I Dogs: Relevance to Human

MPS1?(Dickson P et al 2008)

Liver

Spleen

Lymph node

Renal cortex

Renal medulla

Lung

Heart valve

Myocardium

Synovium

Cartilage (rib)

40020035302520151050

Nontol

0.58 mg/kg

Iduronidase level (U/mg protein)

A B

Liver

Spleen

Lymph node

Renal cortex

Renal medulla

Lung

Heart valve

Myocardium

Synovium

Cartilage (rib)

2000–200

Tol

0.58 mg/kg

% Change vs. Nontol 0.58 mg/kg

6004002000

30

Fabry Disease

• X-linked LSD: deficiency of a-galactosidase

• Glycosphingolipids (globotriaosylceramide-Gb3) accumulate and

alter the morphology and function of many cell types, including

vascular endothelium, visceral parenchyma, and some central and

peripheral neurons.

• Highly heterogeneous disease course with clinical manifestations

varying widely in onset and severity among patients. Initial

symptoms include acroparesthesia, anhidrosis, and angiokeratoma

but renal insufficiency, cardiac involvement, and cerebrovascular

complications commonly arise in mid-adulthood, reducing life

expectancy

• rh-a galactosidase received accelerated approved in 2003 based on

a surrogate endpoint: clearance of Gb3 from renal vascular

endothelium31

Males

(N=571)

Most Male Patients with Fabry Disease Fail to Tolerize to rh-agalactosidase with Continued Treatment

(Wilcox WR et al 2012)

Females

(N=251)

Seroconverted, not tolerized (n=13) 5%

Seroconverted, then tolerized (n=47) Seroconverted, then tolerized (n=18)

Seronegative (n=220)

Seronegative

(n=155)

Seroconverted, not

tolerized (n=369)

32

65%

Evidence that Antibody Response Affects

Optimal Activity of ERT in Fabry Disease

• Correlation of disease biomarkers with antibody

response in patients with Fabry Disease.

• Immune tolerance to ERT improves tissue

penetration and substrate reduction in patients and

animal models

33

Correlation of Antibody Titer with Substrate Accumulation in

Dermal Capillary Endothelium:

Reflects Accumulation in Critical Target Endothelia?(Benichou et al 2009)

34

Dosage Level of ERT Reveals Strong Effect of Antibodies on Substrate Excretion

0

Me

an u

rine G

b-3

(ug/m

g c

reatinin

e)

*

Seronegative

(n=3)

100

400

500

200

300

*

Lowest

titers (n=6)

Intermediate

titers (n=5)

Highest

titers (n=7)

Baseline

1.0 mg/kg period (weeks 0-24)

0.3 mg/kg period (weeks 25-96)

*p < 0.05, different from baseline

* *

*

Lubanda JC et al 2009 1:6400-256001:100-800 <1:3200 35

0

Urinary

Gb3 n

mol/24 h

our

0

years

8

Neutralizing Antibody Positivity Correlates with

Higher Substrate Excretion Levels in Patients with Fabry

2 4 6

1000

3000

4000

Upper limit controls

2000

AB+ AB–

Rombach et al 2012 36

0

lysoG

b3 n

mol/L

0

years

2 4 6

50

100

150

AB+

AB–

Upper limit controls

Antibodies to a-Galactosidase Diminish Enzyme

Penetration of Target Tissues in KO Mice(Ohashi et al 2008)

A-G

al A

enzym

e a

ctivity

(nm

ol/h/m

g)

40

30

20

10

0

Injection mixture

*

Kidney

A-G

al A

enzym

e a

ctivity

(nm

ol/h/m

g)

15

10

5

0

Injection mixture

*

Lung

37

• Preponderance of evidence indicates that moderate

to high titer antibody response to ERT diminishes

tissue penetration, reduces clearance of substrate,

and thus, diminishes efficacy of ERT.

• Given the safety of prophylactic tolerance induction

regimens, strong consideration should be given to

prophylactic tolerance induction in patients with

LSDs at high risk of mounting such responses to

ERT.

38

NORD-FDA Workshop on Immune Responses to

Enzyme Replacement Therapies:

Role of Immune Tolerance Induction

June 9, 2014

39

• Develop disease-specific biomarkers and endpoints

to assess the effect of anti-drug antibodies and

immune tolerance induction on efficacy

• Prophylactic immune tolerance induction should be

strongly considered in patients who are at risk of

developing immune responses to ERT

Conclusions and Questions

• A preponderance of evidence indicates that persistent, moderate to high

titer or neutralizing antibody responses interfere with ERT uptake and/or

activity in critical target tissues and thus very likely diminish efficacy.

• Prophylactic immune tolerance induction allows for unimpeded ERT activity,

diminishing tissue damage, and reducing the intensity and duration of

immune suppression associated with therapeutic tolerance induction

protocols

• Given the very favorable safety experience with the prophylactic tolerance

induction protocol in Pompe (worst case scenario), should tolerance

induction be considered in all CRIM negative and high risk CRIM positive

patients with LSDs?

• Immune tolerance to ERT has additional potential benefits:

– Reducing or eliminating immune response to potentially more highly efficacious

therapies: biobetter ERT, gene therapy and exon skipping approaches to therapy

– Establish tolerance to enzyme to diminish immunogenicity and enhance

engraftment in the setting of transplant 40

Acknowledgements

• FDA

– Daniela Verthelyi, Susan Kirshner, Emanuela Lacana, OBP

– Jessica Lee, Laurie Muldowney, Andrew Mulberg, Lynne Yao,

OND

– Anne Pariser, OTS

• Academia

– Priya Kishnani, Nancy Mendelsohn, Yoav Messinger

– Jeffrey Bluestone, Lawrence Turka, ITN

• Industry

– Susan Richards

41

42

Risk of Developing Additional White Matter Lesions Correlates with Substrate LysoGb3 Level

0

Hazard

ratio

0

LysoGb3 (nmol/L)

8020 40 60

2

5

6

3

4

1

Rombach et al 201243