The Immuno-Oncology CompanyBATTLING CANCER WITH BISPECIFIC ANTIBODIES

NON-CONFIDENTIAL

20 May 2015

20 May 2015

COMPANY SNAPSHOT

Blue-chip Investors

Raised $ 60 M in VC funding

Lead therapeutic: start of clinical trials in Feb 2015.

Bispecific antibody-based, technology platform – partnership with ONO pharmaceutical

Pipeline: 5 Immuno-Oncology therapeutics in clinical trials by Q2/18

HQ Utrecht, The Netherlands - 38 employees

NON-CONFIDENTIAL

Adapted from Bispecifics Antibody Therapeutics Market (2014 Roots Analysis)

Bispecific Antibody Leader

20 May 2015 NON-CONFIDENTIAL

CURRENT PIPELINE – Q2 2015

Drug Targets disease Discovery IND enabling Phase I/II

MCLA-128

HER2 x HER3Solid

tumors

MCLA-117

CD3 x CLEC12A

AML

MCLA-122

EGFR x HER3Solid

tumors

MCLA-134

PD1 x TIM-3Solid

tumors

MCLA-xxx

iMOD x iMOD.

Solidtumors

MCLA-yyy

Cancer stem cell targets

Solid tumors

for outlicensing

Not disclosed AID Partnered ONO PHARMACEUTICAL

AID = autoimmune disease

20 May 2015 NON-CONFIDENTIAL

PIPELINE Q1 2015 → Q2 2018

Drug Targets disease 2015 2016 2017 2018

MCLA-128 HER2 x HER3Solid

tumors

MCLA-117 CD3 x CLEC12A AML

MCLA-122 EGFR x HER3Solid

tumors

MCLA-134 PD1/PD-L1 x YYYSolid

tumors

MCLA-xxx iMOD x iMODSolid

tumors

MCLA-yyycancer stem cell

target combinationsSolid

tumors

for outlicensing

Single agent

Combination

Single agent

Combination

Phase I/II

Clinical batch Mfg & non clinical safety studiesDiscovery

Tox batch Mfg

optional

mezz proceeds IPO proceeds

20 May 2015 NON-CONFIDENTIAL

STRATEGY – WHY BISPECIFIC ANTIBODIES

Large target combination

space

Improved specificity/targeting

Novel mode of action

Attractive pharmaco-economics

Functional screening

Developability

20 May 2015

MISSION & OVERALL STRATEGY

Develop differentiating therapeutics to cure cancer patients

Bispecific antibodies (Biclonics®) that kill tumor cells and recruit the immune system for prolonged survival

NON-CONFIDENTIAL

revive T cells to kill

T cell

CTLA-4

PD-1

TIM-3

LAG-3

BTLA

VISTA

CD28

OX40

GITR

CD137

CD27

HVEM

? ?

T cell Tumor cell

activate/recruite T cells to kill

Fc-silenced

kill the tumor (stem) cell

Tumor cell

ADCC-enhanced

20 May 2015 NON-CONFIDENTIAL

DISCOVERY AND DEVELOPMENT OF BICLONICS®

phage displayMeMo® transgenic mouseCommon light chain (cLC)

Human antibodies

stability: > 60 passagesyield: > 1 g/Lscalability: 2000 Lformulation: standard

ManufacturabilityStability like IgG

normal pK in mice/cynobehaviour like IgG in antibody stress tests

Biclonics®: full length IgG human bispecific

antibodies

CHO

CH3: > 99% pure Biclonics®

Fc region engineering ®

Dependable IgG format with true platform

characteristics

CH2: Fc-silencing

Fc-silencing

ADCC-enhanced

Low fucosylation: enhanced ADCC

cLC cLC

20 May 2015 NON-CONFIDENTIAL

PRODUCT STRATEGY - ONCOLOGY

Cancer stem cells

Kill the cells that cause relapse and

are resistent to most therapies

Target combinations of

growth factor receptors for

ADCC-enhanced tumor cell killing

Receptor tyrosine kinases

Activate T cells irrespecive of specificity to

selectively kill tumor cells

T cellretargeting

Modulate immune checkpoint

molecules to unleash tumor-specific T cells

Immune-modulation

Steps in Biclonics® discovery:• generation of high quality panels of common light chain human monoclonal antibodies

• functional screening of > 1000 Biclonics® for lead panel identification

• final lead selection after multiple in vitro assays and in vivo animal models

CONFIDENTIAL

BICLONICS® DISCOVERY PROCESS - OVERVIEW

6/1/2015 9

Target pair for immunization and phage selections

Functional screening in cell-based assays

Production of ~1000 different Biclonics®

Lead Biclonics®

selection

Generation of large panels of human antibodies

9-12 months

for functional screens

1.

2.

3.

1 June 2015 9

Functional screening of thousands of different Biclonics® supports the identification of differentiating therapeutics

20 May 2015 NON-CONFIDENTIAL

DISCOVERY STRATEGY – FUNCTIONAL SCREENING

-60

-40

-20

0

20

BxPC3 ligand independent assay

BxPC3 EGF + HRG dependent assay

% n

orm

alized

cell g

row

th

Cell growth

stimulation

inhibition

Biclonics® with superior inhibition of cell growth

Functional screen of 750 Biclonics® for inhibition/ stimulation of cancer cell growth (EGFR x HER3)

Best in class anti-cancer drug

without heregulin

heregulin

MCLA-128 (HER2 x HER3)KEY PRECLINICAL DATA

20 May 2015

NON-CONFIDENTIAL

20 May 2015 NON-CONFIDENTIAL

MCLA-128 FOR TARGETED THERAPY IN SOLID TUMORS

MCLA-128: HER2 x HER3 Biclonics® for HER2+ solid tumors

First-in-Human Study:

first patient dosed on February 03, 2015

High unmet medical need designed to overcome inherent and acquired resistance to HER2-targeted therapies

Attractive clinical development phase I/II design is focused on biomarker defined patient populations and yields early safety and efficacy data

Unique mode of action dual action: blocks HER2/HER3-driven growth and escape; enhanced ADCC for immune effector cell engagement

Tumor cell

NK cell

In contrast to trastuzumab + pertuzumab and HER3 monoclonal antibodies, MCLA-128 completely inhibits heregulin-driven cancer cell growth.

20 May 2015 NON-CONFIDENTIAL

MCLA-128: UNIQUE MODE OF ACTION

% heregulin -driven growth

0

1

2

3

4

Erk1

/2

Akt

se

r47

3

Akt

th

r30

8

Fold

ch

ange

in p

ho

sph

ory

lati

on

SKBR-3 cell line stimulated with heregulin

heregulinT + PMCLA-128

N87 HER2-amplified cell line stimulated with heregulin

LJM 716

MM 121

AMG-888

In contrast to trastuzumab + pertuzumab, MCLA-128 inhibits the growth of cell lines resistant to HER-2 targeted therapies • JIMT-1 is an aggressive breast cancer line resistant to lapatinib, trastuzumab +

pertuzumab and T-DM1).

20 May 2015

MCLA-128: UNIQUE MODE OF ACTION

0 20 40 600

50

100

Days

Percen

t su

rviv

al

NON-CONFIDENTIAL

MCLA-128: > 80% reduction in tumor size

mice dosed 4qw @ 2.5 mg/kg

0 20 40 60

100

1000

Vehicle

MCLA-128

Trastuzumab

+ Pertuzumab

Days

Tu

mo

r v

olu

me (

mm

3)

MCLA-128: > 50% survival after 60 days

vehicle

MCLA-128

T + P

vehicle

MCLA-128

T + P

MCLA-117 (CD3 x CLEC12A)KEY FACTS – DATA - DIFFERENTIATION

20 May 2015

NON-CONFIDENTIAL

Tumor (stem) cell

CD3

20 May 2015

BICLONIC® ENGAGERS FOR IMMUNOTHERAPY

MCLA-117: CD3 x CLEC12A Biclonics® for AML

High unmet medical need little change in standard treatment in 40 years; no cure available; increasing patient population

Rapid iv administration and IgG-like dosing schedules; attractive clinical development

superior to antibody fragments; eligible for Orphan Drug Designation ( EU/US); high chance of break-through designation (FDA);

Unique mode of action retargeting T cells via novel AML target with restricted tissue expression; kills tumor (stem) cells

NON-CONFIDENTIAL

T cell AML blastFirst-in-Human Study:

Q1, 2016

a myeloid differentiation antigen only expressed on certain blood cells

present on 95% of newly diagnosed and relapsed AML

selective expression on AML tumor stem cells

• not present on normal hematopoetic stem cells

• not present on red blood cell and platelet precursor cells

20 May 2015

CLEC12A – RESTRICTED TISSUE EXPRESSION

NON-CONFIDENTIAL

100

75

50

25

0AML BM Normal BM

% C

LEC

12

AC

D3

4+C

D3

8-

cells

%

rBM

CLEC12A expression on AML stem cells

20 May 2015

MCLA-117 EFFICIENTLY MEDIATES AML TUMOR CELL KILLING

Recruits and activates T cells to lyse CLEC12A -expressing autologous AML tumor cells.

MCLA-117 induces antigen-specific T cell activation and proliferation

NON-CONFIDENTIAL

CFSE

Ctrl IgG

CD3 IgG

TT x CD3

Ctrl Biclonics®

MCLA-117

Biclonics®

Total T cells CD8 T cellsCD4 T cells

Ctrl IgG

CD3 IgG

CD3xTTctrl Biclonics®

MCLA-117Biclonics®

Total T cells CD4 T cells CD8 T cells

CSFE

cou

nts

T cell AML blast

Specific and efficient lysis of a patient’s AML tumor cells by low numbers of T cells present in primary samples

T cell population expands as a result of MCLA-117

20 May 2015

MCLA-117 EFFICACY IN PRIMARY AML MATERIALS (I)

NON-CONFIDENTIAL

CLEC12A

Isotype

CLEC12A expression on AML blasts

CD3

CD

34

CD3

CD

34

Day 0

Day 10ctrl Biclonics®

Day 10 MCLA-117

93%

5%

81%

16%

1%

96%

T cell expansion

Tumor cell killing

Biclonics® for immunomodulationUNCOVERING THE RIGHT TARGET COMBINATIONS FOR DIFFERENTIATING THERAPEUTICS

20 May 2015

NON-CONFIDENTIAL

Breakthrough of the Year

2013

Time

Ove

rall

surv

ival

control

Immunotherapy combinations

standard of care

immunotherapy

Improving survival of cancer patients

‘Lifting the curve’

What target combination will trump?

• increase frequency and/or duration of responses in patients

• manageable toxicity (autoimmunity)

Merus - three different approaches based on Biclonics®:

• block two checkpoint inhibitory pathways

• block a checkpoint inhibitory pathway and provide a costimulatory signal

• target an overexpressed signalling receptor & an immunomodulatory pathway

20 May 2015 NON-CONFIDENTIAL

BICLONICS® IN CANCER IMMUNOTHERAPY

T cell

PD-1

TIM-3

CTLA-4

LAG-3

BTLA

VISTA

OX40

CD28

GITR

CD137

CD27

HVEM

? ?agonistic blocking

PD-1 x TIM-3

PD-1 x OX-40

dual targeting of 2 antigens on the same cell leads to improved target selectivity over normal tissues

• that express only one target or express low levels of targets (same cell)

• over-expression of a tumor target may direct bispecific to the tumor environment

20 May 2015 NON-CONFIDENTIAL

BISPECIFIC - MONOVALENCY

combination A B

tumor + +

normal + -

Tumor cell

Normal cell

overexpression A B

tumor +++ +

normal + +

Normal cell

Tumor cell

targeting A B

tumor +++ +

normal + +

T cellTumor

cell

favorable toxicity profile compared to a combination of antibodies ??

20 May 2015

A UNIQUE MODULAR DISCOVERY STRATEGY

PD-1 centric

NON-CONFIDENTIAL

BBB

TIM-3 AAA

CCC

iMOD targets

ZZ

EGFR ZZ

ZZ

RTK targets

PD-L1 centric

Antibody panels are combined in the Biclonics® format for functional screening

• antibody panels for 6 IMOD targets generated and 4 more planned for 2015

• screen in functional assays for differentiating activities of Biclonics ongoing with current focus on PD-1 and PD-L1 centric approaches (one arm = PD-1 or PD-L1)

Reporter cell line

Exhausted T cells

(HIV, Miha)

TILS

Lead

Functional screens

Unique technology suite

• human bispecific antibodies based on the proven IgG format

• high throughput functional screening for the identification of bispecific antibodies with unique functional properties

• manufactured using industry standard processes

• predictable in vivo behavior associated with IgG format

20 May 2015 NON-CONFIDENTIAL

HIGHLIGHTS

T cell AML blast

Tumor cell

A pipeline of differentiating therapeutics in oncology

• modes of action that can not be achieved with conventional therapeutic antibodies

• recruitment of the immune system for unprecedented tumorcell killing

An extremely attractive investment opportunity

Thank you for your attentionTON LOGTENBERG

CEO

20 May 2015

NON-CONFIDENTIAL