Corporate Presentation (TSX: BLU)

Roberto BelliniPresident and Chief Executive OfficerTwitter: @rbellini

March 17, 2017

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Forward Looking StatementsCertain statements contained in this news release, other than statements of fact that are independentlyverifiable at the date hereof, may constitute “forward-looking statements” within the meaning of Canadiansecurities legislation and regulations. Such statements, based as they are on the current expectations ofmanagement, inherently involve numerous important risks, uncertainties and assumptions, known andunknown, many of which are beyond BELLUS Health Inc.'s control. Such risks factors include but are notlimited to: the ability to obtain financing, the impact of general economic conditions, general conditions in thepharmaceutical industry, changes in the regulatory environment in the jurisdictions in which BELLUS HealthInc. does business, stock market volatility, fluctuations in costs, changes to the competitive environment dueto consolidation, achievement of forecasted burn rate, potential payments/outcomes in relation to indemnityagreements and contingent value rights, achievement of forecasted pre-clinical and clinical trial milestonesand that actual results may vary once the final and quality-controlled verification of data and analyses hasbeen completed. In addition, the length of BELLUS Health Inc.’s drug candidates development process, theirmarket size and commercial value, as well as the sharing of proceeds between BELLUS Health Inc. and itspotential partners from potential future revenues, if any, are dependent upon a number of factors.Consequently, actual future results and events may differ materially from the anticipated results and eventsexpressed in the forward-looking statements. The Company believes that expectations represented byforward-looking statements are reasonable, yet there can be no assurance that such expectations will proveto be correct. The reader should not place undue reliance, if any, on any forward-looking statements includedin this news release. These forward-looking statements speak only as of the date made, and BELLUS HealthInc. is under no obligation and disavows any intention to update publicly or revise such statements as a resultof any new information, future event, circumstances or otherwise, unless required by applicable legislation orregulation. Please see BELLUS Health Inc.’s public filings with the Canadian securities regulatoryauthorities, including the Annual Information Form, for further risk factors that might affect BELLUSHealth Inc. and its business.

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INNOVATIVE DRUGSIDENTIFY. DEVELOP. TRANSACT.

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Team with strong track record of execution

Company Highlights

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• Core project targeting chronic cough, potential multi-billion dollar drug class

− BLU-5937: potential best-in-class drug for clinically validated P2X3 target

− First in class program acquired by Merck in 2016 for $US500M after Phase 2

− Clear and efficient development path for value creation

• Partner in three additional pre-Phase 2 programs

• Cash runway to end of 2018

Strong core project, balanced pipeline, multiple prospects

Pipeline Overview

PRECLINICAL PHASE 1 PHASE 2 PHASE 3

BLU-5937Chronic Cough Wholly-ownedWholly-owned

Partnered IP (Revenue Share)Partnered IP (Revenue Share)KIACTASarcoidosis

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Partnered IP (Revenue Share & Royalty)Partnered IP (Revenue Share & Royalty)

ALZ-801Alzheimer’s Disease

Partnered IP (Revenue Share & Royalty)Partnered IP (Revenue Share & Royalty)

AMO-01Fragile X Syndrome

BLU-5937: Investment Thesis

Low risk profile, best-in-class potential for large market with unmet need6

Merck acquired a P2X3 antagonist program in 2016 for US$500M based on positive Phase 2 data in chronic cough

Potential multi-billion dollar drug class in therapeutic indication lacking innovation

Orally bioavailable small molecule P2X3 antagonistHigh potency and P2X3 selectivityPotential for improved efficacy and safety profileClear, efficient development path to demonstrate superiority

Attractive financial termsLeverages core competencies: clinical, BD, financingExperienced, motivated team to drive project to success

Right-sized transaction for BELLUS

BLU-5937: potential to be best-in-class drug

addressing high unmet need

P2X3 receptor: validated target in

emerging drug class for chronic cough

Chronic Cough

Cough lasting > 8 weeks, associated with:

• Pulmonary diseases (asthma, COPD, lung cancer, IPF)

• Extra-pulmonary disorders (post-nasal drip, gastro-oesophageal reflux)

• Use of certain drugs (ACE inhibitors)

• No identifiable cause (unexplained chronic cough)

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ImplicationsCharacteristics

Time and resource intensive for healthcare system

• Responsible for 30M physician visits per year in U.S.

• 38% of pulmonologist outpatient practice

• Unexplained and refractory chronic cough require time and resource intensive differential diagnosis

Chronic cough affects ~10% of the adult population

Major Impact on Patients

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ExhaustionSleep deprivation Retching/vomiting

IncontinenceHeadache

Hoarse voiceChest painRib fracture

Embarrassment of coughing in publicInterference with

lifestyle, work & leisureDifficulty speakingSocial exclusion

DistressAnger

AnxietyDepression

Psychosocial complications

Social complications

Physical complications

Chronic cough has significant impact on patient quality of life8

Few Treatment Options

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Gabapentin/PregabalinOpioids

Centrally acting

Some efficacy demonstrated in small

studiesHigh incidence of adverse effects

Very limited efficacySome efficacy but cause sedation/confusion

Constipation and nausea

Potential for addiction

OTC Products

No novel approach approved to address chronic cough in 40 years9

Pathophysiology: Hypersensitivity of Cough Reflex

Coughing trigger (ex. asthma attack)

Cellular damage causes enhanced ATP release in

respiratory tract

ATP activates P2X3 receptors on airway sensory neurons

Airway hyper-excitability

Chronic Cough

Cell injury

Drug targeting P2X3 has strong rationale for reducing cough frequency 10

ATP andCytokines

Primary afferent(A or C-fiber)

ATP

ATP

Receptors

P2X3

P2X3-containingPrimary afferent

Modified from Purinergic Signaling (2012) 8 (Suppl 1)

P2X3 Family Involved in Taste Perception

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Taste stimuli

ATP release from taste buds

ATP activates P2X3 and P2X2 receptors on taste

sensory neurons

Taste perception

Drug with high selectivity for P2X3 could limit or eliminate taste alteration side effect without compromising effect on cough

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Kinnamon et al., 2013. A Taste for ATP: neurotransmission in taste buds. Frontiers in Cellular Neuroscience. Vol 7, Article 264 pp. 1-7.

mouse tongue

LegendP2X3

P2X2

P2X3 HighlySelective Antagonist

P2X3 & P2X2Double knockout

Taste loss

P2X3Single knockout

P2X2Single knockout

Mild taste alterationMild taste alteration

Expected mild/no taste alteration

P2X3 Antagonist

Knockout Mice

Drug Approach

P2X3 MildlySelective Antagonist

Significant taste alteration

Clinically Validated Molecular Target

Opportunity for highly selective P2X3 antagonist with better efficacy/safety profile to become class leader

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50 to 75%reduction in cough frequency

50 to 100%of patients experience taste disturbance

(likely due to low P2X3 selectivity)

Adbulqawi et al., 2016. P2X3 receptor antagonist (AF-219) in refractory chronic cough: a randomised, double-blind, placebo-controlled phase 2 study. Lancet. Vol 385, No 9974 pp. 1198-1205.Kitt et al., 2016. A Phase 2 Dose-Escalation Study with AF-219, a P2X3 Antagonist for the Treatment of Chronic Cough. American Thoracic Society 2016 International Conference - San Francisco.

Treating chronic cough with low selective P2X3 antagonist results in:

Meaningful Effect Problematic Side Effect

Strong drug candidate profile with potential to be best in P2X3 class

BLU-5937 Profile

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Kgscale CMC

Broad and comprehensive IP to

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HighPotency (low nM) and Selectivity for

P2X3

HighPotency (low nM) and Selectivity for

P2X3

Orally bioavailable

small molecule

Orally bioavailable

small molecule

Zerosafety findings of concern to-date

Preclinical Efficacy: Cough Response

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Treatments (control, BLU-5937) were administered orally (p.o.) two hours prior to tussive agent exposure: citric acid (0.1 M, aerosol) and histamine (0.6 mM, aerosol); n=6 animals (guinea pig) per group *p<0.05

Oral administration of BLU-5937 dose-dependently reduced the frequency of cough in a guinea pig model

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0

5

10

15

20

25

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Control 0.3 mg/kg p.o. 3 mg/kg p.o. 30 mg/kg p.o.

Total coughs (average)

Control BLU-5937

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10-40% patients with refractory / unexplained chronic cough

10-40% patients with refractory / unexplained chronic cough

10% of US adult population has chronic cough

10% of US adult population has chronic cough

Estimated addressable patients in major pharma markets:

6.3M

Large Addressable Market

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275M U.S. adults

27.5M U.S. chronic cough

patients

2.75M Unexplained/

refractory patients

Major pharma markets include the U.S., Europe top five countries and JapanSong et al., 2015. The global epidemiology of chronic cough in adults: a systematic review and meta‐analysis. Eur Respir J. Vol 55 pp. 1479‐1481Zanasi et al., 2014. Chronic and unexplained cough. (Published online) Vol 4, No 3 pp. 159‐164

Key Development Milestones

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Value creating milestones throughout development path

2017 2018 2019/2020

IND-enabling studies Phase I: assess dose and taste effect

Phase II: demonstrate antitussive effect

Complete IND preclinical study

package

Assess safety, tolerability, PK, effect on taste in healthy subjects

Single ascending dose and multiple ascending

dose studies

Assess safety, PK and antitussive effects in patients

suffering from chronic refractory cough

Dose response study with crossover design

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Partnered Programs

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Genetic disorder affecting ~180K in U.S.IP licensed in 2014 for low double-digit royalty/ single digit revenue shareRas-ERK inhibitor that reverses disease abnormalities in preclinical modelStart of Phase 2 expected in 2017

Principally respiratory disease affecting ~100K in U.S.IP licensed in 2009 with double digit revenue shareReduces key inflammatory markers mediated by serum amyloid AAuven to confirm plans to enter Phase 2/3 study in 2017

ALZ-801 for Alzheimer’s

disease (AD)(Alzheon Inc)

KIACTATM for Sarcoidosis

(AuvenTherapeutics)

AMO-01 for Fragile X Syndrome

(AMO Pharma)

IP licensed in 2013 for mid single-digit royalty/revenue shareInhibitor of amyloid aggregationPreparing for Phase 3 for AD patients homozygous for apolipoprotein E gene

Financial Highlights

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Stock Information (March 14, 2017)

Ticker TSX: BLUShares (basic) 66.9MShares (fully diluted) 71.7MDaily Volume ~150KMarket Capitalization ~$20M

Key Financials1

Cash $7.5MCash Runway Q4 2018

Fully Diluted Shareholder OwnershipBellini Family ~25%Power Corporation ~25%1as at December 31, 2016 and pro forma to upfront considerations of Thallion and NEOMED transactions

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Board of DirectorsDr. Francesco Bellini (Chair) Franklin Berger Charles Cavell

Hélène Fortin Pierre Larochelle Muriel Lortie

Joseph Rus Dr. Martin Tolar Roberto Bellini

ManagementRoberto Bellini, President and Chief Executive Officer

Dr. Denis Garceau, Senior Vice President, Drug DevelopmentFrançois Desjardins, Vice President, Finance

Tony Matzouranis, Vice President, Business Development

Governance and Shareholders

LAROSE FORTIN CA Inc.

Execution of BLU-5937 plan in chronic cough:

• IND-enabling studies

• Market assessment

• Present further animal data

Progress in other projects

• KIACTA Phase 2/3 in Sarcoidosis

• AMO-01 Phase 2 in Fragile X

• Alzheon financing

Milestones

Past ExecutionAttracted more than $100M to funding projects

Executed multiple global clinical studies including Phase 3

Completed multiple transactions (in-licensing, partnering, out-licensing)

Milestones (12 months)

Multiple upcoming milestones to drive value20