Unlocking the potential of gene silencing for everyone · SLN360, Silencing LP(a) to treat CVD • Lipoprotein (a) (“LP(a)”) is a significant risk factor for premature coronary

January 2019

Corporate Presentation

Non-Confidential Presentation

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© Silence Therapeutics 2019 2

Silence Therapeutics’ Summary

© Silence Therapeutics 2019

Notes: 1 MDS = Myelodysplastic syndrome2 As of 30 June 2018and £=$1.3

3

HQ in London

R&D in Berlin

Approx. 50 employees across both sites

• $44m of cash2 extends runway to key clinical milestones. Strong Financial Position

• Reproducible, proprietary gene silencing (RNAi) therapeutics platform, rapidly generating internal pipeline and diversifying out-licensing options

Valuable Platform

• SLN124 (beta-thalassemia & MDS1) planning to enter the clinic in H2 2019 after promising efficacy signals in animal modelsHaematology

• Focused on targeting indications in rare diseases & large population targets, including new medicine for cardiovascular disease (SLN360)

Target Selection

• Over 15 years of tenured oligonucleotide R&D expertise; growing clinical team, and experienced biopharma management team

Strong Experienced

Team

Silence: Operational Highlights

• New leadership in place with the recruitment of Dr David Horn Solomon as Chief Executive Officer, an experienced public company biotech CEO, board member and biotech investor.

• The field is advancing: Gene-silencing as a therapeutic modality was granted its first drug approval by the U.S. Food and Drug Administration (FDA) on August 10 2018 for Onpattro™, validating RNAi as a class of drugs that now have a clear path to market.

• Positive regulatory feedback and promising data in clinically relevant animal disease models representative of iron overload disorders, increases confidence in Silence’s lead candidate SLN124, with initiation of Phase 1b study anticipated in H2 2019.

• New RNAi medicine advanced – SLN360 for the treatment of LP(a) associated cardiovascular disease. Positive preclinical data generated in NHP. CTA/IND planned for H2 2020.

• Out-licenced technology, QPI-1002 for potential prevention of acute kidney injury progressed to Phase 3 dosing by Quark Pharmaceuticals, Inc.


Experienced Leadership Team


Richard Jenkins VP Clinical Development

David Horn SolomonCEO & President CEO

Rob Quinn, Interim CFO

Laura Roca-Alonso, Ph.D. VP Corporate Development

Linnea Elrington,VP Human Resources

Since 2018 Since 2017

Marie Wikstrom LindholmVP Technology Innovation

Deep Background in Discovery & Development of RNA Therapies With Strong Biopharma Experience

5



Michael Mulqueen, VP BD & Licensing

Since 2017

Our Pipeline



Out-Licensed Technology to Quark Pharmaceuticals

Iron Overload Disorders:SLN124 for β-Thalassemia and Myelodysplastic Syndrome

• SLN124 is an GalNAc-siRNA targeting TMPRSS6 in hepatocytes. Inhibition of TMPRSS6 induces Hepcidin expression, thereby reducing circulating iron levels

• Initially targeting β-Thal and MDS. Expansion opportunities include Hereditary Hemochromatosis


Overview Value and Drivers Current Status and Next Steps

• Peak US/EU sales of $1.4bn (MDS) and $300m (β-Thal) – at 20% market share

• CTA planned in Q2 2019, with first patient dosed in Phase 1b study in Q3 2019

• First interim results expected in mid 2020

• Phase 1b planned to run over 2019-2021 (c. $20m)

• Planning to progress straight into pivotal trials in 2022 (c. $50m) with launch expected in 2026

SLN360, Silencing LP(a) to treat CVD

• Lipoprotein (a) (“LP(a)”) is a significant risk factor for premature coronary heart disease & unstable angina and is associated with increased risk of myocardial infarction (MI).

• SLN360 demonstrates strong LP(a) reduction in serum and is now ready to enter IND-enabling studies.

• Phase 1 studies to commence in 2020.

Opportunity

• Entry Indication: people with familial LP(a) elevation at high risk of cardiovascular disease (CVD) {~600,000 in US and Europe}

• Expansion Potential: subjects treated with statins (+/- anti-PCSK9) who are still at risk of CV events associated with elevated LP(a) {>20M in US and Europe}


GalNAc-siRNA Platform Technology


Modifying Molecular Design to Enhance Performance


siRNA modification pattern

GalNAc compositionEnd stabilization

Linker composition

• Modification pattern: reduced number of non-natural modifications• End stabilization: increased circulation half-life, activity and duration of action• Linker: simplified synthesis, increased activity • GalNAc: lower dosing via optimization of number & placement of monomers

Evolving a better molecule: Increasing activity & duration, lowering COGS and dosing

• Gen 1 Gen 2 Gen 3 Gen 4

Evolution of Our GalNAc-siRNA Platform


2016 2017 2018

GEN2

GEN1 GEN3

GEN4

• Patents filed• Entered pipeline in Q2 2018• Advantages: Improved safety profile and

COGS, and FTO further strengthened

• Served to transition to conjugate technology, establishing baseline performance. No FTO

• Patents filed• Clinical stage in 2019 (SLN124) and used in

late pre-clinical stage programmes (SLN226, CVD)

• Robust performance, competitive to peers

• Patents filed• Further optimisation ongoing• Plans to enter the pipeline in early 2019• Advantages: improved potency, COG and

safety

Different GalNAc unit numbers and positioning

Reduced non-naturalmodifications

Reproducibly silencing disease-associated genes using our proprietary platform technology


Platform technology with freedom to operate: GalNAc-siRNA, able to mediate highly specific gene silencing in hepatocytes (liver) – “Specificity upon specificity”

Patient friendly: Subcutaneous delivery and infrequent dosing (monthly or longer). Well tolerated.

~7,000 genes operate in the liver. Silence can target any of them by adapting the siRNA sequence, using the same technology.

Target 1 Target 2

P B S s iR N A 20 .0

0 .5

1 .0

No

rmal

ised

tar

get

mR

NA

C T R L s iR N A 10 .0

0 .5

1 .0

No

rmal

ised

tar

get

mR

NA

SLN124 for the treatment of

Iron Overload Disorders


Treatment of Iron Overload Disorders (IOD)

14

GOAL• Provide an effective and safe novel treatment option for

patients with iron overload conditions with infrequent s.c. dosing

RATIONALE• Target a key modulator in iron regulation with a GalNAc-

siRNA molecule providing a highly specific, effective & safe option through inhibition of a disease relevant target gene (TMPRSS6) expressed in hepatocytes

CURRENT STAGE• Preclinical development with plans to enter clinical

development in H2 2019 after Q2 2019 CTA filing

Affected organs

Iron overload disorders:• Myelodysplastic Syndrome

(MDS)• β-Thalassemia• Hereditary

Haemochromatosis• HSC transplant• Aplastic Anaemia• Sideroblastic AnaemiaIf untreated, iron accumulation in organs leads to severe organ damage,


Market Opportunity of SLN124


~40,000 TDT1

~20,000 NTDT2

US and EU patients

>100,000

β-Thalassemia

MDS3

SLN124 aims to:1. Reduce organ iron levels &2. Enhance erythropoiesis

Reduced transfusion frequency & Secondary iron overload burden

Standard of Care

Benefits of SLN124 Advantages v CompetitionSoC:

Transfusions + Chelators

Luspatercept

Gene therapy

Hepcidin mimetics

Antisense RNA

Quality of Life

Safety

Compliance

Organ iron levels

Less frequent dosing

Advantages Competition

Notes: 1 TDT = Transfusion Dependent Thalassemia 2 NTDT = Non Transfusion Dependent Thalassemia 3 MDS = Myelodysplastic Syndrome

SLN124 Mechanism of Action: Increasing Hepcidin by Silencing its Repressor TMPRSS6


• TMPRSS6 (Transmembrane Protease, Serine 6) is a negative regulator of the BMP/SMAD signaling pathway

• Inhibition of TMPRSS6 in hepatocytes induces Hepcidin expression

• Hepcidin reduces absorption of dietary iron and the release of iron from cellular storage, thereby reducing circulatory iron levels

• The liver is the predominant source of Hepcidin

TMPRSS6

BMPRHJV

SMADP

Hepcidin induction

BMP

P

Enterocytes

Ferroportin

Iron recycling

Hepatocytes

Fe

Iron absorption

Macrophages

Fe

HAMPDNA

Hepcidin

Ferroportin

Reduces iron levels

Improves erythropoiesis

1 Increases Hepcidin levels

Reduces anemia & iron overload

2 43Silencing TMPRSS6

1P B S

1 3T M P R S S 6 s iR N A

60

1 0

2 0

3 0

4 0

Ser

um

iro

n [

µmo

l/L]

w e e k s1P B S

1 3T M P R S S 6 s iR N A

60 .0

0 .5

1 .0

No

rmal

ised

TM

PR

SS

6 m

RN

A

w e e k s

SLN124 Lowers Iron Levels for at Least 6 Weeks after Single Administration in Mice


TMPRSS6 mRNA (liver) Iron (serum)

Study design

• Long-lasting functional mRNA KD in liver • Reduction of serum iron levels for at least 6 weeks• Well tolerated with long duration of action in mice

wk 6d1 wk 1 wk 3

SC, n=4 mice, 3 mg/kg

P B S3

C T R L1

T M P R S S 6 3

0 .0

0 .5

1 .0

1 .5

2 .0

No

rma

lis

ed

TM

PR

SS

6 m

RN

A

m g /k gs iR N A

P B S3

C T R L1

T M P R S S 6 3

0

1 0 0

1 8 0

2 0 0

2 2 0

2 4 0

[µg

Iro

n/g

dry

tis

su

e]

m g /k gs iR N A

P B S3

C T R L1

T M P R S S 6 3

0

1 0 0

2 0 0

3 0 0

Se

rum

Iro

n [

µg

/dL

]

m g /k gs iR N AP B S

3C T R L

1 T M P R S S 6

30

2 0 0

4 0 0

6 0 0

8 0 0

Se

rum

He

pc

idin

[n

g/m

L]

m g /k gs iR N A

Therapeutic Activity of SLN124 in a Disease Model of Hereditary Haemochromatosis (HFE-/- mice)


• Dose-dependent and robust silencing of TMPRSS6 mRNA in the liver

• Increase in serum hepcidin levels• Reduction of serum and kidney iron levels to

physiological values

TMPRSS6 mRNA (liver) Hepcidin (serum) Iron (serum)

Iron (kidney)

Study designd1 wk 3

SC, n=6-7 HFE-/- mice

Collaboration withProf. Dr. Martina MuckenthalerHeidelberg University, Germany

Kruskal-Wallis test with uncorrected Dunn‘s test against non-targeting control CTRL

p=0.0007

p<0.0001

p=0.0042

p<0.0001

p=0.0263

p=0.0325

Collaboration withProf. J. Vadolas & Dr. Grigoriadis Monash Medical Centre/Melbourne, Australia

SLN124 Reduces ROS and Improves RBC Parameters in a β-Thalassemia Disease Model


• Reduction of ROS to levels in healthy mice• Normalisation of reticulocyte proportion and improvement of haematocrit• SLN124 significantly improves erythropoiesis in animal model for

β-Thalassemia intermedia

Study designd1 wk 5

SC, n=6-8 Hbbth3/+ mice

wk 2

ROS = reactive oxygen species; RBC = red blood cells

Reactive oxygen species (ROS) Reticulocyte proportion Haematocrit

-W T m ic e

P B S C T R LT h 3 /+ m ic e

T M P R S S 60

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

8 0 0

Med

ian

FI

s iR N A

p = 0 .0 0 6 9

-W T m ic e


T M P R S S 60

5

1 0

1 5

2 0

2 5

Ret

icu

locy

tes

[%]

s iR N A

p = 0 .0 0 4 2

-W T m ic e


T M P R S S 60

3 0

4 0

5 0

6 0

Hae

mat

ocr

it [

%]

s iR N A

p = 0 .0 0 7 6

We are Planning to Initiate a Multicentre, Randomised, Placebo Controlled Phase 1b in 2019

This is a 2 part first-in-human, multicenter, randomized placebo controlled single ascending and multiple dose study to assess the preliminary safety, tolerability, PK and efficacy of SLN124 administered subcutaneously for the treatment of non-transfusion dependent thalassemia and low risk myelodysplastic syndrome.

Study design

> Part A:

• Single dose escalation study to evaluate the dose response to SLN124 with a view to identify the most appropriate dose to bring forward into the multiple dose portion of the study

• Primary aim to determine the safety and tolerability of SLN124 for the treatment of non-transfusion dependent β-thalassemia

> Part B:

• Bring forward the most efficacious and best tolerated dose to evaluate multiple administrations of SLN124 on hematinic parameters in patients with β-thalassemia and MDS

• Primary aim to determine the safety and tolerability of multiple doses of SLN124 for the treatment of non-transfusion dependent β-thalassemia and low risk myelodysplastic syndrome

20© Silence Therapeutics 2019

2019 2020 2021 2022Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2

The Phase 1b will Include β-Thalassemia and MDS Patients with Interim Results Expected in 2020

21

14w 4w Cohort 1, SD, P=2 A=6, 0.3 mg/kg

Interim analysis, potential DP

Interim analysis and preliminary analysis on multiple dose

Part A analysis and final decision on multiple dose

Cohort 5, MD, P=5 A=10, x mg/kg20w 12w

Cohort 6, MD, P=5 A=10, x mg/kg

5w

Part B flash results

β-Thalassemia

MDS

Cohort 3, SD, P=2 A=6, 3 mg/kg10w 4w

Cohort 2, SD, P=2 A=6, 1 mg/kg

Cohort 4, SD, P=2 A=6, 10 mg/kg10w 4w

Optional cohort 4a, SD, P=2 A=6, x mg/kg10w 4w

5w


10w 4w


LEGEND

xw Cohort rec = x weeks

yw Follow up = y weeks

SD = Single dose

MD = Multiple dose

P = Number of subjects receiving placeboA = Number of subjects receiving active agent

xw LPLV to DBL = y weeks

20w 12w


SLN124 Summary

• Preclinical package: Robust data generated in several disease models.

• Status: Non-clinical development work ongoing, with CTA filing expected in Q2 2019. Orphan Designation granted for β−Thalassaemia and application planned for MDS.

• Clinical plans: Phase 1b planned in patients (β−Thalassaemia and MDS). Network of KOL’s established.

• Dosing regimen: Patient-friendly, with monthly or less frequent dosing expected and subcutaneous administration route.

• Regulatory: Positive feedback received at Scientific Advice meetings with both the UK (MHRA) and German (BfArM) national regulators.

• SLN124 is commercially viable compared to gene therapy, which has a heavy burden on patients versus a monthly SubQ.


SLN360 for the treatment of

LP(a)


LP(a) is an Independent Risk Factor for CVD


> LP(a) is a validated target in humans. LP(a) excess isdetected in patients with premature CVD:

> LP(a) is only minimally confounded by typical riskfactors such as smoking, blood pressure or diabetes.

> High unmet need - Apheresis is the only approachthat can reduce LP(a) levels by a large amount,however is invasive and burdensome: procedurelasts 70min-2h, can be performed up to every week

Peak aortic Jet velocity (m/s)

Patients with lowLp(a) levels

Patients with highLp(a) levels


Up to 2-fold higher

hemodynamic progression rate

on echo and need for AVR


Tsimikas 2017

Adjustment for additional risk factors does not produce dramatic changes

• High LP(a) associates with CHD, unstable angina,myocardial infarction (MI) and progression of aortic valvecalcification and coronary artery vasopasm (CAVS)

• High LP(a) levels have been shown to predict a 2-4 foldincrease in risk of MI and CVD

• Adding LP(a) levels ≥80th percentile to conventional riskfactors improves MI and CHD risk prediction

LP(a) has Prothrombotic, Proinflammatory and Proatherogenic Properties


Proinflammatory

ProthromboticProatherogenic

Macrophage IL-8 expression

Monocyte cytokine releaseMonocyte cytokine release

Monocyte chemotaxis/transmigration

Carries MCP-1

EC binding

Upregulation of adhesion molecules

SMC proliferation

Proteoglycan matrix binding

Foam cell formation

Necrotic core formation

Lesion calcification

Plasminogen activation

Fibrin degradation

EC PAI-1 expression

TFPI activity

Platelet responsiveness

LP(a

) act

iviti

es

Adapted from Tsimikas et al 2017

> The LP(a) complex is composed of two different proteins encoded by the LPA and the APOB genes and a lipid particle, both expressed in hepatocytes

Our approach to reducing LP(a) levels


Proof of mechanism achieved> Highly competitive dataset generated in non-human primates

> Over 85% KD at NADIR for single 3mg/kg injection with 50% KD still observed 2 months post-treatment

> Multiple dosing at a 3mg/kg dose level resulted in sustained reduction of Lp(a) serum levels (>90%) for at least over two months after first dose (max ~>95% KD). Similar outcome after single subcutaneous 9mg/kg injection

26

SLN360 summary


Rationale> LP(a) is a low-density lipoprotein produced predominantly by the liver and composed of

Apo(a) and Apo B, both hepatocyte expressed genes.

> Genetically defined high LP(a) serum levels are unaffected by diet and exercise and arean independent risk factor for CVD. There is no specific LP(a) targeting therapy availableat the moment.

> An LPA silencing siRNA would provide a specific, safe and durable approach forreducing LP(a) levels in high risk patients.

Our Programme> A potent lead sequence has been selected and tested in vivo in non-human primates

(NHP).

> Proof of mechanism has been achieved in NHP: dose dependent reduction in both LPA(liver mRNA) and LP(a) (serum protein) observed, with max 95% KD observed aftermultiple dosing.

> Our drug compares positively against published data by competitors, suggesting asuperior performance.

>IND/CTA is planned for H2 2020

Expected Newsflow & Company Milestones


H1 2019 H2 2019

SLN124

File CTA X

First In Human Dosing X

SLN360

Lead candidate nomination X

2018 New Targets

pPOC in mice X

Final candidate nomination X

Platform Strengthening

Gen4 toolbox validation and in use X

Quark Out-License in QPI-1002

First interpretative results for DGF Phase 3 study expected X

Thank you

Documents

Unlocking the potential of gene silencing for everyone · SLN360, Silencing LP(a) to treat CVD • Lipoprotein (a) (“LP(a)”) is a significant risk factor for premature coronary