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N o v e m b e r 2 0 1 9

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DISCLAIMER

Matters discussed in this presentation may constitute forward-looking statements. The forward-looking statements contained in thispresentation reflect our views as of the date of this presentation about future events and are subject to risks, uncertainties, assumptions, andchanges in circumstances that may cause our actual results, performance, or achievements to differ significantly from those expressed orimplied in any forward-looking statement. Although we believe that the expectations reflected in the forward-looking statements arereasonable, we cannot guarantee future events, results, performance, or achievements. Some of the key factors that could cause actualresults to differ from our expectations include our plans to develop and potentially commercialize our product candidates; our planned clinicaltrials and preclinical studies for our product candidates; the timing of and our ability to obtain and maintain regulatory approvals for ourproduct candidates; the extent of clinical trials potentially required for our product candidates; the clinical utility and market acceptance of ourproduct candidates; our commercialization, marketing and manufacturing capabilities and strategy; our intellectual property position; and ourability to identify and in-license additional product candidates. For further information regarding these risks, uncertainties and other factorsthat could cause our actual results to differ from our expectations, you should read our Annual Report on Form 20-F for the year endedDecember 31, 2018, as filed with the Securities and Exchange Commission on March 5, 2019 and our other filings we make with theSecurities and Exchange Commission from time to time. We expressly disclaim any obligation to update or revise the information herein,including the forward-looking statements, except as required by law. Please also note that this presentation does not constitute an offer to sellor a solicitation of an offer to buy any securities.

This presentation concerns products that are under clinical investigation and which have not yet been approved for marketing by the U.S.Food and Drug Administration. It is currently limited by federal law to investigational use, and no representation is made as to its safety oreffectiveness for the purposes for which it is being investigated. The trademarks included herein are the property of the owners thereof andare used for reference purposes only. Such use should not be construed as an endorsement of such products.

This presentation also contains estimates and other statistical data made by independent parties and by us relating to market size and growthand other data about our industry. This data involves a number of assumptions and limitations, and you are cautioned not to give undueweight to such estimates. In addition, projections, assumptions and estimates of our future performance and the future performance of themarkets in which we operate are necessarily subject to a high degree of uncertainty and risk.

33

Our Focus: Women (15-49)

Uterine Fibroids

Endometriosis

Preterm Labor

A WOMEN’S HEALTH

INVESTMENT OPPORTUNITY

Two compounds in three indications aimed at large markets with enormous unmet need ‒ Uterine Fibroids: Linzagolix Phase 3

‒ Endometriosis: Linzagolix Phase 3

‒ Preterm Labor: OBE022 Phase 2

Multiple value creating opportunities inQ4 2019/2020‒ Linzagolix Ph3 PRIMROSE 2 Fibroid readout

‒ OBE022 PROLONG PTL Ph2a interim update

‒ Linzagolix Ph3 PRIMROSE 1 Fibroid readout

‒ Target NDA/MAA for Linzagolix (fibroids)

Worldwide rights with broad IPestate

4

FOCUSED ON UNMET NEEDS IN

WOMEN’S REPRODUCTIVE HEALTH

LINZAGOLIX OBE022

Potential to delay preterm birth to improve

newborn health and reduce medical costs

Potential to optimize estrogen reduction

without use of synthetic hormones

5

SEASONED LEADERSHIP TEAM

Ernest Loumaye

MD, PhD, OB/GYN

CEO and Co-founder

Beth Garner

MD, MPH

Chief Medical Officer

Tim

Adams

Chief Financial Officer

Jean-Pierre

Gotteland, PhD

Chief Scientific Officer

Wim Souverijns, PhD

Chief Commercial

Officer

6

MULTIPLE LATE-STAGE PROGRAMS TO DRIVE VALUE

* Primary and secondary endpoints met

PHASE 1 PHASE 2 PHASE 3 MARKET SIZE NEXT MILESTONES

LINZAGOLIX(OBE2109)

Oral GnRH

receptor antagonist

4M diagnosed and

treated in U.S.

24W Primary endpoint data Q4 2019

24W Primary endpoint data Q2 2020

NDA /MAA Q4:2020/Q1:2021

2.5M diagnosed and

treated in U.S.

Maybe another 2.5M

undiagnosed

Initiated Ph3 Q2 2019

Positive results 2018/19

OBE022

Oral PGF2α

receptor antagonist

500,000 annual cases

in each of U.S and

Europe

Interim update in 60 patients Q4 2019

Pre-clinical/Phase 1 complete

NOLASIBAN

Oral oxytocinreceptor antagonist

Evaluating potential

re-positioning

Positive IMPLANT 2 Ph3 Results

IMPLANT 4 Ph3 missed primary

endpoint

Uterine Fibroids – Ph3 PRIMROSE 1 U.S.

Preterm Labor – Ph2a PROLONG

IVF – Ph3 IMPLANT 2/4 EU

Uterine Fibroids – Ph3 PRIMROSE 2 EU & U.S.

Endometriosis – Ph3 EDELWEISS 2 U.S.

Endometriosis – Ph3 EDELWEISS 3 EU & U.S.

Endometriosis – Ph2b EDELWEISS

Preterm Labor – Ph1

*

77

NOLASIBAN CURRENT STATUS

Clinical development program targeted at improving pregnancy and live birth rates in infertile women undergoing embryo transfer (ET) following IVF

First European Phase 3 trial (IMPLANT 2) showed 11% absolute increase in ongoing pregnancy (p=0.034) and live birth rates (p=0.025) in Day 5 fresh ET

Confirmatory Phase 3 IMPLANT 4 trial did not meet the primary endpoint of improved 10-week ongoing pregnancy (p=0.745)

Current clinical development program discontinued, IMPLANT 4 safety follow-up to be completed

Potential repositioning of nolasiban to be assessed

IVF= in vitro fertilization

Linzagolix (OBE2109)

O P T I M I Z I N G A P P R O A C H F O R

R E D U C I N G E S T R O G E N TO T R E AT

U T E R I N E F I B R O I D S A N D

E N D O M E T R I O S I S

9

FOCUSED ON UNMET NEEDS IN

WOMEN’S REPRODUCTIVE HEALTH

LINZAGOLIX

Potential to optimize estrogen reduction

without use of synthetic hormones

10

LINZAGOLIX: REDUCING

ESTROGEN TO TREAT

UTERINE F IBROIDS &

ENDOMETRIOSIS

Validated MoA

Oral GnRH receptor antagonist

More than 2,100 women treated through clinical trials

Once a day dosing

No interaction with food or other drugs

GnRH antagonist have an immediate onset of action, preventing gonadotrophin release through receptor blockade, leading to rapid suppression of LH and estradiol

Competitively prevent endogenous GnRH from binding and activating its pituitary receptor

Induce neither downregulation nor desensitization of the receptors

GnRH antagonist (blocker)

GnRH

antagonist

Ovary

GnRHHypothalamus

Anterior pituitary gland

FSH, LH

Uterus

Estradiol

11

0

20

40

60

80

100

120

25mg 50mg 75mg 100mg 200mg

(whiskers represent

10% / 90% percentile)

OUR AIM – A SIMPLE,

CONVENIENT, EFFECTIVE

AND SAFE LONG -TERM

TREATMENT

* Add Back Therapy (ABT) ActivellaTM

Endometriosis PatientsWeek 24 Modeled E2 Data

Linzagolix Daily Dose (mg) for 24 Weeks

Linzagolix 75mg

Linzagolix 200mg + estradiol +

norethindrone acetate*

E2

concentration

(pg/ml)

Preferred first

line optionIf needed, higher

dose option with

ABT available

(whiskers represent 10% / 90% percentile)

Target Range

Linzagolix provides a consistent dose-dependent reduction in E2 levels

12ABT OR NO ABT? THAT IS THE QUESTION.

ANSWER FROM PHYSICIANS A

RESOUNDING “NO” !

Gynecologist survey in U.S. shows high preference of no ABT as first-line therapy

Preferred dosing is to start low and go higher as needed

Trend toward patients preferring avoidance of hormone therapy vs. endogenous estrogen management

ABT comes with HRT black box warning*

* Activella U.S. FDA Label: cardiovascular disorders, breast cancer, endometrial cancer, and probable dementia

1

2

3

4

Quintiles IMS Survey (2017)

30 U.S. Gynecologists

PRODUCT 1:

High dose of oral GnRH antagonist with mandatory add-back (as the only option)

High dose of oral GnRH antagonist with mandatory add-back OR low dose of oral GnRH

antagonist without add-back

PRODUCT 2:

preferred

Product 1

preferred

Product 2

Reasons:• No time to try different

dosages in severe patients• Convenient option

Reasons:• More flexibility with

add-back therapy

93%

2 out of 30 respondents 28 out of 30 respondents

7%

13

UTERINE F IBROIDS: A LARGE

MARKET WITH UNMET NEED

Total U.S. costs estimated at up to

from direct costs, lost

workdays and complications

$34B /yr

35millionwomen in the U.S. suffer from fibroids

70%+of women have fibroids by age 50

Qualityof LifePremenopausal women may experience heavy menstrual bleeding, anemia, bloating, infertility, pain and swelling

600,000Hysterectomies are performed annually in the U.S.

300,000Are because of uterine fibroids

4millionwomen in the U.S. are treated annually for fibroids

13

14

UTERINE F IBROIDS: A LARGE MARKET WITH UNMET NEED

Current Treatment Options are Limited

Oral Contraceptives and NSAIDs

LUPRON® Injections-GnRH agonist

Surgical Interventions

OC’s often ineffective to

reduce bleeding

OC contraindications

NSAID side effects

Initial symptom flares

Full E2 suppression: ABT*

mandatory >6 months

Only approved for short-term use

Hysterectomies are common

and end fertility

High rate of recurrence after

conservative surgery

* Add Back Therapy (ABT)

15

ENDOMETRIOSIS: AN

EMOTIONALLY AND PHYSICALLY

PAINFUL CONDITION

Total U.S. costs estimated at up to

$22B /yr

2.5millionwomen in the U.S. are treated annually for endometriosis

Qualityof LifePremenopausal women may experience pelvic pain, pain during intercourse and defecation, infertility and emotional distress

10%Endometriosis affects up to

in the general population

50% in the infertile population

60% in patients with chronic pelvic pain

176millionwomen worldwide suffer from endometriosis

60%of women will feel symptoms by age 16

15

16

ENDOMETRIOSIS: A LARGE MARKET WITH UNMET NEED

Incomplete pain response as

disease progresses

OC contraindications

NSAID side effects

Not ideal for younger, chronic

population

Full E2 suppression: ABT*

mandatory >6 months

Initial symptom flares

Hysterectomies are common

and end fertility

High rate of reconcurrence after

conservative surgery

Current Treatment Options are Limited

Oral Contraceptives and NSAIDs/Opioids

LUPRON® Injections-GnRH agonist

Surgical Interventions

* Add Back Therapy (ABT)

17

(whiskers represent

10% / 90% percentile)

BENEFITS OF GNRH RECEPTOR

ANTAGONISTS VS AGONISTS

Competitively preventing endogenous GnRH from binding and

activating its pituitary receptor

Contrasting with GnRH agonists, inducing neither

downregulation, nor desensitization of the receptors

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Allows for partial or full estrogen suppression

Rapid reversibility

Partial estrogen suppression does not require ABT

Immediate action: no initial flare & worsening of symptoms

Oral dosing enhances patient compliance

Consistent PK/PD allows for QD & no food effect

More suitable for chronic therapy

18

UTERINE F IBROIDS PH 2 DATA: L INZAGOLIX REDUCED

MENSTRUAL BLEEDING & UTERINE VOLUME (NO ADD BACK)

p < 0.01 *

Two sample t-test

(vs. Placebo)28.98

24.18

13.63

7.99

Placebo OBE2109

50mg

OBE2109

100mg

OBE2109

200mg

*

KLH1202 Trial: % of Days with Bleeding

During 12-week Treatment Period

KLH1202 Trial: Time to No Bleeding for

Uterine Fibroids Patients

KLH1202 Trial: Change in

Uterine Volume over Time

19PRIMROSE 1 & 2 : PHASE 3 CLINICAL TRIALS

FOR THE TREATMENT OF UTERINE F IBROIDS

PRIMROSE 1100% U.S. sites

PRIMROSE 270% Europe

30% U.S. sites

• IND granted in April 2017

• Aiming at supporting the registration of two regimens of administration

MAIN STUDY (N=500, 100/arm) FOLLOW UP

24 WEEKS

PRIMARY ENDPOINT:Responder-HMB Reduction

Q4:19/Q2:20

Placebo + placebo add-back

100mg + placebo add-back

100 mg + add-back

200 mg + placebo add-back

Placebo + placebo add-back

100mg + placebo add-back

100 mg + add-back

200 mg + placebo add-back

200 mg + add-back

200 mg + add-back

28 WEEKS24 WEEKS

SCREENING

SCREENING FOLLOW-UP100 mg + add-back

200 mg + add-back

100mg + placebo add-back

200mg + add-back

200 mg + add-back

FOLLOW-UP100 mg + add-back

200 mg + add-back

100mg + placebo add-back

200mg + add-back

200 mg + add-back

Placebo + placebo add-back

8-14 WEEKS

20

PHASE 2B EDELWEISS CLINICAL TRIAL:

ENDOMETRIOSIS PATIENTS

**BMD: Bone Mineral Density* Titration after 12 weeks based on E2 serum level at weeks 4 and 8

MAIN STUDY FOLLOW UP

Enrollment 328 patients, ~65/arm

50 sites in U.S. (n=177)

14 sites in EU (n= 151)

PRIMARY ENDPOINT: VRS PAIN SCORE RESPONDER RATE

JUNE 2018

SECONDARY ENDPOINT: BMD**

SEPTEMBER 2018

RESULTS:

1H 2019

8–14 WEEKS

LEAD-IN

50mg daily

100mg daily

200mg daily

75mg daily

75mg daily*

PLACEBO

12 WEEKS 12 WEEKS 24 WEEKS

50mg daily

200mg daily

75mg daily

*Titrated dose 50-100mg

100mg daily

OPTIONAL EXTENSION:

6M + 6M FOLLOW-UP

FOLLOW-UP

21

LINZAGOLIX PH2B ENDOMETRIOSIS:

KEY DOSES MET EFFICACY ENDPOINTS

75mg partial suppression dose nearly as effective as 200mg full suppression dose

Potential point of differentiation

Overall Pelvic Pain (%) Responder (0-3 VRS)

28,5

0

68,258,3

78,9 84,1

Week 12 Week 24

Plc 75mg 200mg

Dysmenorrhea (%)

Non-menstrual Pelvic Pain (%)

Responder (0-3 VRS)

Responder (0-3 VRS)

34,5

61,5

70,8

56,3

77,3

Week 12 Week 24

Plc 75mg 200mg

37,1

58,5

72,9

47,7

72,7

Week 12 Week 24

Plc 75mg 200mg

***

******

*

* p value <0.05 ** p value <0.01 *** p value <0.001 for linzagolix doses compared to placebo

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* p value <0.05 ** p value <0.01 *** p value <0.001 for linzagolix doses compared to placebo

LINZAGOLIX PH2B ENDOMETRIOSIS:

SECONDARY ENDPOINTS

-0,39

-0,59

-0,7-0,79

-1

Week 12 Week 24

Plc 75mg 200mg

4,3

36,3

27,1

80,975

Week 12 Week 24

Plc 75mg 200mg

-0,78

-1,87

-2,2

-1,7

-2,5

Week 12 Week 24

Plc 75mg 200mg

Dyspareunia Amenorrhea Dyschezia

Δ from Baseline (0-3 VRS) Proportion %Δ from Baseline (0-10 NRS)

*

***

***

***

23

PHASE 2B EDELWEISS CLINICAL TRIAL

75MG EFFECTIVE WITHOUT SIGNIF ICANTLY AFFECTING BMD

-4

-3

-2

-1

0

1

2

Lumbar Spine Total hip Femoral neck

200mg

100mg

75mg FD

50mg

Placebo

Mean % change in BMD from baseline to 24 weeks (12 weeks for placebo)

-2.2% cut-off requiring ABT *

* ABT: Add Back Therapy (estradiol + norethindrone acetate)

75mg 200mg

Error bars are 95% CIs

-1.6% lower bound Cl for

75mg

-3.6% lower bound Cl for

200mg

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LINZAGOLIX PHASE 3 ENDOMETRIOSIS TRIALS:

EDELWEISS 2 AND 3

MAIN STUDY FOLLOW UP

11±5 WEEKS6 MONTHS TREATMENT 6 MONTHS EXTENSION STUDY

6 MONTHS

CO-PRIMARY ENDPOINT:DYS/ NMPP RESPONDER ANALYSIS

LEAD-IN

INITIATED 1H:19

200mg daily + ABT

75mg daily

PLACEBO

75mg daily

200mg daily + ABT

75mg daily

200mg daily + ABT

FOLLOW-UP

25

LINZAGOLIX STRATEGY AND DIFFERENTIATION:

OBSEVA is the only company developing a SIMPLE & SAFE

non-ABT regimen for both indications

Optimal Administration

Second-line option: full suppression

First-line option: partial suppression

Once a day – no food interaction – no DDI

Both low dose and high dose

Preferred option – only one active drug

In development for both endometriosis and uterine fibroids

Second line – combination of 3 active drugs

In development for both endometriosis and uterine fibroids

1

2

3

OBE022

P O T E N T I A L TO D E L AY P R E T E R M B I RT H

TO I M P R O V E N E W B O R N H E A LT H A N D

R E D U C E M E D I C A L C O S T S

27

FOCUSED ON UNMET NEED IN

WOMEN’S REPRODUCTIVE HEALTH

OBE022

Potential to delay

preterm birth

28

PRETERM DELIVERY: LIFE ALTERING & COSTLY

Preterm labor is the

Tremendous avoidable medical & societal cost

1in10babies are born premature

premature deaths in 2015

28

of death of children under 5 years of age

LEADING CAUSE

more than 1million

Average cost for a preterm infant (U.S.)

$50K Average cost per survivor infant born 24-26 weeks

$195K

Babies surviving early birth face greater likelihood of lifelong disabilities

U.S. economic burden

$26B+ $16.9B+ U.S. Infant medical care costs

2929

PRETERM LABOR:

LACKING EFFECTIVE SOLUTIONS

Limited present therapeutic alternatives

Treatments have limited efficacy and restrictive safety risks

No approved drug therapy in U.S. – off-label use of nifedipine,

NSAIDs such as indomethacin

Ex-U.S., atosiban (Tractocile) approved as bolus + infusion up

to 48 hours

30

MODE OF ACTION OF PGF 2 RECEPTOR ANTAGONIST TO

CONTROL PRETERM LABOR

PGE2 PGF2

PGHS -1/2 = COX1/2

EP1

EP3

EP2

EP4FP

PGH2

contractrelaxcontract

Selectively

blocks the

PGF2

receptor

Has the potential to

treat preterm labor

with improved

safety over NSAIDs

OBE022

UTERUS:

Phospholipids

Arachidonic Acid

x

31

O B E 0 2 2 I N H I B I T S C O N T R A C T I O N S O F H U M A N U T E R I N E M U S C L E

A N D D E L AY S P R E T E R M L A B O R I N P R E C L I N I C A L M O D E L S

* p<0.05, ** p<0.01, *** p<0.001 vs DMSO vehicle control, # p<0.05, ## p<0.01, ### p<0.001 vs Atosiban 6nM

OBE022 inhibited oxytocin-induced contractions

of human uterine muscle tissue (n=6)

OBE022 delayed endotoxin (LPS)-induced

preterm delivery in mice

** p<0.01 vs vehicle, * p<0.05 vs combination

**

32

OBE022 NON-CLINICAL SAFETY DEMONSTRATED:N O A D V E R S E F E TA L S I D E E F F E C T S A S S E E N W I T H I N D O M E T H A C I N

No induction of vasoconstrictionof ductus arteriosus

No platelet

aggregation inhibition

No induction of vasoconstriction

of kidney vessels

Rat Fetus Newborn Rabbit

33

OBE022:

PROLONG PH2A STUDY

PART A Study design:Open-label, single arm

Atosiban + OBE022

Loading dose of 1,000mg followed by

500mg twice a day for 7 days

24-month Infant FU

Q1:18

Final Part A: Main analysis

Q4:18 Q4:20 / Q1:21

Endpoint:Positive PK/PD and safety

8 out of 9 patients completed 7 days of dosing

without delivery

Main Study completed

Dosing:7 days / 9 patients

Preliminary safety& PK analysis

34

PART A – OBE022 SAFE AND WELL TOLERATED

8 of 9 patients did not deliver within 7 days of treatment start

28 29 30 31 32 33 34 35 36 37 38 39 40

1

2

3

4

5

6

7

8

9

Patien

t #

WEEK:

Start of OBE022 treatment

43 days

81 days

58 days

39 days

44 days

18 days

51 days

51 days

1 day

Very preterm Moderate to late preterm Term

Days since start of OBE022 treatment

35

OBE022:

PROLONG PH2A STUDY

PART B

Study design:Double-blind, randomized Atosiban + OBE022

versus Atosiban + Placebo

24-month Infant FU

Q1:18

Final Part B: Main analysis

2H:20 2H:22

Endpoint:Complete 7 days of dosing without delivery

Main Study completion120 patients

Dosing: 7 days up to 60 patients

Followed thru delivery

Interim Update

60 patients

Interim Update

30 patients

IDMC Reviews

3636

Our Focus: Women (15-49)

Uterine Fibroids

Endometriosis

Preterm Labor

A WOMEN’S HEALTH

INVESTMENT OPPORTUNITY

Two compounds in three indications aimed at large markets with enormous unmet need ‒ Uterine Fibroids: Linzagolix Phase 3

‒ Endometriosis: Linzagolix Phase 3

‒ Preterm Labor: OBE022 Phase 2

Multiple value creating opportunities inQ4 2019/2020‒ Linzagolix Ph3 PRIMROSE 2 Fibroid readout

‒ OBE022 PROLONG PTL Ph2a interim update

‒ Linzagolix Ph3 PRIMROSE 1 Fibroid readout

‒ Target NDA/MAA for Linzagolix (fibroids)

Worldwide rights with broad IPestate

3737

FINANCIAL OUTLOOK

2019/2020 investment includes

FOUR ONGOING Phase 3 trials:

S E P T E M B E R 3 0 , 2 0 1 9 C AS H :

$91 million

E X P E C T E D C AS H R U N WAY:

Q1:21 with credit facility

PRIMROSE 1

PRIMROSE 2

EDELWEISS 2

EDELWEISS 3