BELLUS Health : Presentation at Jefferies Global Healthcare Conference in London

Jefferies London Healthcare Conference

Corporate Presentation

NASDAQ/TSX - BLU

November 20, 2019

Forward Looking Statements

Certain statements contained in this presentation, other than statements of fact that are independently verifiable at the date hereof, may constitute "forward-looking statements" within the meaning of Canadian securities legislation and regulations and other applicable securities laws. Forward-looking statements are frequently, but not always, identified by words such as "expects," "anticipates," "believes," "intends," "estimates," "potential," "possible," "projects," "plans," and similar expressions. Such statements, based as they are on the current expectations of management, inherently involve numerous important risks, uncertainties and assumptions, known and unknown, many of which are beyond BELLUS Health's control. Risk factors that may affect BELLUS Health's future results include but are not limited to: the ability to obtain financing, the impact of general economic conditions, general conditions in the pharmaceutical industry, changes in the regulatory environment in the jurisdictions in which BELLUS Health does business, stock market volatility, heavy dependence on licensed intellectual property, fluctuations in costs, changes to the competitive environment due to consolidation, achievement of forecasted burn rate, potential payments/outcomes in relation to indemnity agreements and contingent value rights , achievement of forecasted pre-clinical and clinical trial milestones, reliance on third parties to conduct preclinical studies and clinical trials for BLU-5937 and that actual results may vary once the final and quality-controlled verification of data and analyses has been completed. In addition, the length of BELLUS Health's product candidates development process, their market size and commercial value, as well as the sharing of proceeds between BELLUS Health and its potential partners from potential future revenues, if any, are dependent upon a number of factors. Moreover, BELLUS Health's growth and future prospects are mainly dependent on the successful development, regulatory approval and commercialization of its product candidate BLU-5937. Consequently, actual future results and events may differ materially from the anticipated results and events expressed in the forward-looking statements. BELLUS Health believes that expectations represented by forward- looking statements are reasonable, yet there can be no assurance that such expectations will prove to be correct. The reader should not place undue reliance, if any, on any forward-looking statements included in this presentation. These forward-looking statements speak only as of the date made, and BELLUS Health is under no obligation and disavows any intention to update publicly or revise such statements as a result of any new information, future event, circumstances or otherwise, unless required by applicable legislation or regulation.

Please see BELLUS Health's public filings with the Canadian securities regulatory authorities, including the Annual Information Form, for further risk factors that might affect BELLUS Health and its business.

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Company Overview

BELLUS Overview

Lead Program: BLU-5937

Highly Selective P2X3 Antagonist for Chronic Cough:

• Large population with significant unmet need
• Indication of interest by big pharma (e.g. Merck and Bayer)
• Phase 1 suggests best-in-class potential
• Clinically validated target reduces clinical risk
• Phase 2 underway with data expected in mid 2020

Pipeline within a Molecule

2nd indication in chronic pruritus associated with atopic dermatitis with potential for broad applicability in hypersensitization disorders

Cash Runway Beyond Proof-of-Concept

~$100M (C$132M)1 cash position

Robust IP

Patent estate including composition of matter covering BLU-5937 and related compounds expiring in 2034

Experienced Team

Management with track record of execution

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1as of June 30, 2019 and proforma to September 5th, 2019 financing

Strong Leadership and Advisory Group

Management

Roberto Bellini

President & Chief Executive Officer

Dr. Catherine Bonuccelli

Chief Medical Officer

Dr. Denis Garceau

Senior Vice President, Drug Development

François Desjardins

Vice President, Finance

Tony Matzouranis

Vice President, Business Development

Board of Directors

Dr. Francesco Bellini	Roberto Bellini	Dr. Youssef Bennani
Chair
Franklin Berger	Dr. Clarissa Desjardins	Chau Q. Khuong
Pierre Larochelle	Joseph Rus
Clinical Advisory Board
Dr. Jacky Smith (Chair) , MB, ChB, FRCP, PhD	Dr. Lorcan McGarvey , MD, FRCP
University of Manchester		Queen's University of Belfast
Dr. Alan Goldsobel, MD		Dr. Alyn Morice , MD
UCSF; Stanford Medical School		Hull York Medical School
Dr. James Hull , BSc, MBBS, FRCP, PhD, FACSM	Dr. Mandel Sher , MD
Royal Brompton Hospital		University of South Florida

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BLU-5937: Pipeline Within a Molecule

PROGRAM		DEVELOPMENT			STATUS
Indication	Preclinical	Phase 1	Phase 2	Phase 3	Worldwide	Next Anticipated Milestone
Rights

BLU-5937

Refractory

Mid-2020: Topline data

Chronic Cough

Chronic Pruritus

Associated withQ2 2020: Phase 2 initiation

Atopic Dermatitis

• Clinical results demonstrate that BLU-5937, a highly selective P2X3 antagonist, is a differentiated product candidate that has little to no impact on taste perception
• Phase 2 clinical trial to assess the efficacy, safety and tolerability of BLU-5937 in refractory chronic cough patients is underway with results expected in mid-2020

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P2X3 and Chronic Cough

Problem: Refractory Chronic Cough

Cough lasting >8 weeks 0 therapies that are safe

• effective

"I see patients that have been coughing 2

months to 30 years. Within that group, there is a good portion where I am the 8th or 10th doctor."

• Chronic Cough KOL

Significant impact on

quality of life

2.6M

Patients in U.S. with longstanding refractory chronic cough

Multi $B

Market potential

Report 2018 Bluestar BioAdvisors (formerly known as Torreya Insights)

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P2X3 Receptor: A Key Target in Chronic Cough

• ATP gated ion channel in the peripheral sensory nervous system

• Key sensory receptor in transmitting upper airway irritation and triggering cough reflex

• Targeting P2X3 with an antagonist is a clinically validated approach to treating refractory chronic cough

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Proof-of-Mechanism Established by First-in-Class P2X3 Antagonist MK-7264

MK-7264

Effective in reducing cough but with Taste Side Effects

Mechanism:

P2X3 antagonist

Acquired in 2016 for $1.25B

($500M upfront) based on P2 data

and currently in two P3 trials

Cough	Taste
57%	81%
reduction in cough	of patients have
frequency from	taste alteration or
baseline	loss
37%

placebo adjusted reduction in cough frequency

Merck & Co., Inc. (2017). Merck Announces Presentation of Phase 2 Results for MK-7264, an Investigational, P2X3 Receptor Antagonist, Being Evaluated for the Treatment of Chronic	10
Cough. [Press Release]. Retrieved from http://www.mrknewsroom.com/news-release/research-and-development-news/merck-announces-presentation-phase-2-results-mk-7264-inve

Lack of P2X3 Selectivity Results in Taste Effect

P2X3 and P2X2/3: ATP-gated ion channels that transmit sensory signals

COUGH REFLEX:	TASTE:
P2X3 homotrimers have primary	P2X2/3 heterotrimers have
role in cough	major role in taste

OPPORTUNITY:

Highly selective P2X3 antagonist to reduce cough (P2X3 inhibition) and maintain taste (no P2X2/3 inhibition)

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Our Solution: BLU-5937

Our Solution: Highly Selective P2X3 Antagonist

BLU-5937 is a highly selective P2X3 antagonist with key characteristics to treat chronic cough

	BLU-5937
HIGHLY POTENT	HIGHLY SELECTIVE
P2X3 antagonist	P2X3 antagonist
Low nM IC50	~ 1500X selectivity vs P2X3

EQUIVALENT	LITTLE / NO
reduction in cough1	impact on taste2
1vs. MK-7264 in animal studies (see slide 17)	2Bellus Phase 1 data at estimated therapeutic doses of 50-100mg

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BLU-5937 Selectivity Resulted in Differentiated Taste Profile

		Incidence and Severity of Taste Effect AEs at Estimated
		Comparative Therapeutic Doses1
		BLU-5937(50-100 mg)	MK-72642 (50 mg)
		(n=24)	(n=63 )
TRIAL	NCT03638180	NCT02612610
DOSE(S)	50 and 100 mg single dose	50mg BID arm for 12 weeks
and 7 day BID cohorts
SUBJECTS	Healthy volunteers	Refractory chronic cough
TASTE ALTERATION	<5%	48%
PARTIAL TASTE LOSS	0%	24%
COMPLETE TASTE	0%	21%
LOSS
ALL TASTE	<5%	81%
ADVERSE EVENTS

At estimated therapeutic doses and based on clinical trial results to date:

BLU-5937 has significantly improved taste effect profile versus MK-7264

1No head to head clinical trials have been conducted; data derived from different clinical trials in different patient populations and with different dosing
regimes and protocols.	14
2Merck & Co Presentation of gefapixant Phase 2b data at American Thoracic Society 2017

Clinical Data Further Validates P2X3 Target

P2X3 is a clinically validated target, with multiple positive Phase 2 trials, with low and high selectivity P2X3 antagonists

Selective S-600918 Has Comparable Efficacy to Low	Inhibition of P2X3 Linked to Efficacy
Selectivity MK-7264	Inhibition of P2X2/3 Linked to Taste Effect With Low
			Selectivity MK-7264
MK-7264	S-600918
Phase 2b Trial	Phase 2a Trial
57%	53%
vs Baseline	vs Baseline
37%*	32%**
Placebo Adjusted	Placebo Adjusted
Merck & Co ATS Presentation, May 22	Research and Development at
2017; *p<0.01	Shionogi Presentation, March 14,
	2019; **p=0.055

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Market and Competitive Landscape

P2X3 Competitive Landscape1

Best in class selectivity for P2X3 supports potential favorable clinical and commercial profile

		1ST IN CLASS P2X3	2ND GENERATION P2X3	BEST IN CLASS
		ANTAGONIST	ANTAGONISTS	SELECTIVITY FOR P2X3
	Company
	Candidate	MK-7264	BAY '080 &	S-600918	BLU-5937
	BAY '607
	Dosing	15mg /	BID	50mg / 150mg /	50 / 100mg BID
	45mg BID	300mg QD
	P2X3 vs. P2X2/3	3-7x	17-126x2	~ 250x3	~ 1500x
	Selectivity
	Cough efficacy4	High	High	High	High
Taste side effect4	High	Moderate/Low	Moderate/None	Low/None
Developmental Phase	Phase 3	Phase 2	Phase 2	Phase 2
	1No head to head clinical trials have been conducted; data derived from different clinical trials in different patient populations and with different dosing regimes and protocols.
	2Bayer selectivity range of most characterized P2X3 antagonists described in Bayer US patent 10,183,937 (may not be BAY1817080/BAY1902607)
	3S-600918 Phase 2a Presentation, ERS, September 29, 2019					17
	4Effect on taste and anti tussive effect are company estimates based on animal data, clinical data, dose, human P2X3 potency and human P2X3 vs P2X2/3 selectivity

Chronic Cough Market

Potential multi-billion dollar refractory chronic cough market

Large Addressable Patient Population

Comparable Products

263M U.S. adults

Payer discussions and comparable product analysis support $300-$600 per month pricing

10% or 26.3M	2.6M Primary
chronic cough	addressable patients:
patients	treatment refractory
	>1 year

Report 2018 Bluestar BioAdvisors (formerly known as Torreya Insights)

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BLU-5937 Clinical Program

BLU-5937: Phase 1 Trial Design

Design: A randomized, double-blind,placebo-controlled, escalating single dose followed by escalating multiple dose Phase 1 trial conducted in 90 healthy adult subjects

Objective: To test the safety, tolerability, and pharmacokinetic profile of BLU-5937

Single Ascending Dose (SAD)

• N=60 healthy subjects
• 6 cohorts of 10 subjects (8 active; 2 placebo) administered single doses of 50mg to 1200mg
• Food effect tested at 200mg in one cohort

Multiple Ascending Dose (MAD)

• N=30 healthy subjects
• 3 cohorts of 10 subjects (8 active; 2 placebo) administered multiple doses of 100mg, 200mg, and 400mg BID for 7 days

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Phase 1 PK Profile and Dosing

	35000			Cmax
( ng/mL)	30000
25000
20000
15000
Cmax
10000
5000
	0
	0	200	400	600	800	1000	1200	1400

Dose (mg)

	300000			AUC
(ng*h/mL)	250000
200000
150000
100000
AUC
50000
	0
	0	200	400	600	800	1000	1200	1400

Dose (mg)

PK Profile:

• BLU-5937is rapidly absorbed (Tmax ~1h )
• Systemic exposure increases dose-proportionally
• Plasma half-life of 4-9 hours supports BID dosing
• No significant effect of food on PK
• No significant systemic accumulation over 7 days

Dosing:

• Projected therapeutic dose of 50-100mg BID
• Based on achieving targeted receptor inhibition & comparative drug blood levels at effective doses in preclinical and clinical studies of validated comparator

2

21 1

BLU-5937:Well-Tolerated in Phase 1

Incidence of Most Frequent Adverse Events (>5% Incidence) in All Cohorts (SAD + MAD)

AEs	Placebo	50mg	100mg	200mg	400mg	800mg	1200mg	Total BLU-5937
N (%)	(n=18)	(n=8)	(n=16)	(n=16)	(n=16)	(n=8)	(n=8)	(n=72)
Taste Alteration	0 (0%)	0 (0%)	1 (6%)	0 (0%)	6 (38%)	5 (63%)	2 (25%)	14	(19%)
Headache	1 (6%)	0 (0%)	2 (13%)	1 (6%)	1 (6%)	2 (25%)	2 (25%)	8 (11%)
Hypoaesthesia	0 (0%)	0 (0%)	0 (0%)	3 (19%)	2 (13%)	3 (38%)	0 (0%)	8 (11%)
Dizziness	0 (0%)	0 (0%)	0 (0%)	0 (0%)	2 (13%)	1 (13%)	1 (13%)	4	(6%)
Nausea	1 (6%)	0 (0%)	0 (0%)	1 (6%)	1 (6%)	2 (25%)	2 (25%)	6	(8%)
Dyspepsia	0 (0%)	0 (0%)	1 (6%)	0 (0%)	2 (13%)	1 (13%)	0 (0%)	4	(6%)

• No serious adverse event; >80% of AEs were mild; no significant effect on vital signs, ECG, laboratory
• Potential P2X3 class-related side effects include: taste effects, hypoaesthesia, nausea
• One subject had mild liver enzyme elevation (400mg BID) that normalized at follow up; not associated with increased bilirubin

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22

BLU-5937: Minimal Taste Effect at Therapeutic Doses

	Incidence of Taste AEs (All SAD and MAD Cohorts)
	50mg	100mg	200mg	400mg	800mg	1200 mg
	(n=8)	(n=16)	(n=16)	(n=16)	(n=8)	(n=8)	• One subject out of 24 (4%)
							reported taste alteration at
Taste	0 (0%)	1 (6%)	0 (0%)	6 (38%)	5 (63%)	2 (25%)	the anticipated therapeutic
Alteration	doses (50-100 mg)
Partial							• No taste loss or taste
0 (0%)	0 (0%)	0 (0%)	1 (6%)	1 (13%)	0 (0%)	alteration at 200 mg
Taste Loss
							• No complete taste loss at
Complete	0 (0%)	0 (0%)	0 (0%)	0 (0%)	0 (0%)	0 (0%)	any dose
Taste Loss

Minimal incidence of taste AEs at doses to be studied in Phase 2

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RELIEF Phase 2 Trial Design

Phase 2 recruiting with topline data expected in mid-2020

65 refractory chronic cough patients; at >1 year coughing

16 sites in UK and US

Primary endpoint:

Reduction in awake cough frequency using cough recorder

2 patient arms

4 dose levels with forced escalation at 4-day intervals (25/50/100/200mg twice daily)

Safety and tolerability assessment, including taste effect

Matching

Matching

Matching

Matching

♦

♦

♦

♦

♦

♦ Placebo

♦ Placebo

♦

Placebo

♦ Placebo ♦

Matching

Matching

Matching

Matching

♦

♦

♦

♦

♦

Placebo

♦

Placebo

♦

Placebo

♦

Placebo

♦

♦

Cough Recording

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BLU-5937: Beyond Chronic Cough

Potential for Broad Applicability and Building Pipeline in a Product

P2X3 sensitization contributes to irritation and pain

OTHER INDICATIONS LINKED TO P2X3 HYPERSENSITIZATION

• Bladder pain
• Bronchoconstriction
• Chronic pruritus
• Endometriosis pain

• Hypersensitive cough

• Hypertension
• IBS
• Migraine
• Neuropathic pain
• Sleep apnea

Active development at Bellus

Active development at Merck

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Chronic Pruritus Associated with Atopic Dermatitis

Mechanistic Similarities Between Cough and Itch

Animal POC - Atopic Dermatitis Mouse Model

		140
scratches		120
	100	*
spontaneous	(60 min.)	80
60		***
of		40
No.		20			***	***
		0
		Vehicle	BLU-5937	BLU-5937	BLU-5937	U50,488
		3gm/kg
			2mg/kg	10mg/kg	50mg/kg

Number of spontaneous scratches in 60 min of day 8 Calcipotriol (MC903) treated mice pre-injected with vehicle, 2, 10, or 50 mg/kg test BLU-5937, or 3 mg/kg U50,488. (n = 10 mice per group),*p < 0,05, ***p < 0.0001, one-way ANOVA. Data are represented as mean ± S.E.M. U50,488: kappa opioid

agonist

Poster presented at European Society for Dermatological Research on

September 21st, 2019

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AD Chronic Pruritus Market

Large Diagnosed Patient

Population in the US…

16.9M

3M

2.25M

…with 40-50% Patients

Having Residual Itch

Limitations of Current Therapies

Corticosteroids	Significant side effects
Antihistamines	Limited effect
Immuno-	Toxicity
suppressants
Dupixent	Cost & low
reimbursement rate

Report 2019 Bluestar BioAdvisors

Phase 2 proof of concept trial in ~100 mild/moderate atopic dermatitis

patients with moderate/severe chronic pruritus expected to start in Q2 2020

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IP and Corporate Summary

Robust Intellectual Property Portfolio

Composition of matter IP in place to 2034

• U.S. and international patent estate covering BLU-5937 and related compounds

• Composition of matter patent for BLU- 5937 and related imidazopyridines granted in the U.S., Europe, Japan and China

• Composition of matter patents for BLU- 5937 expire in 2034 (not including potential patent term extension)

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Stock and Financial Information

Capital Structure1

55.4M basic shares

59.8M fully diluted shares

1as of September 23rd, 2019

Cash Position

Cash position of $100M / C$132M1

1as of September 30, 2019

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Potential Catalysts

Key Anticipated Milestones Over Next 12 Months

Past Execution

• Animal POC in cough (June 2017)
• C$20M financing (December 2017)
• BLU-5937Phase 1 data with potential strong taste profile (November 2018)
• C$35M financing (December 2018)
• Phase 2 recruiting (July 2019)
• Animal POC in pruritus associated to atopic dermatitis (July 2019)
• $79M NASDAQ IPO (September 2019)

12 Months Milestones

BLU-5937 in chronic cough:

• Phase 1 abstracts at ATS (May 21) and ACC (June 8)
• KOL Event with Phase 2 Principal Investigator Dr. Jacky Smith (July 16th in New York City)
• Phase 2 first patient enrolled (July 2019)

• Phase 2 top-line data expected (mid 2020)

BLU-5937 in chronic pruritus associated with AD

• Animal POC poster presentation at European Society for Dermatological Research Conference (Sept 21)

• Phase 2 first patient enrolled (Q2 2020)

Competitor catalysts:

• Shionogi Phase 2 data
  • Bayer Phase 2 data
  • Merck MK-7264 pipeline: Phase 2 in endometriosis pain

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