Astria Therapeutics : Corporate Presentation

Astria Corporate Presentation

June 2024

1

Forward Looking Statements

This presentation contains forward-looking statements within the meaning of applicable securities laws and regulations including, but not limited to, statements regarding: our expectations regarding the potential significance of the initial results from the Phase 1b/2 ALPHA-STAR clinical trial of STAR-0215 and the timing and nature of additional results from the Phase 1b/2 ALPHA-STAR clinical trial of STAR-0215, and that favorable results from such trial will allow us to move directly into a Phase 3 trial of STAR-0215 as a potential treatment for hereditary angioedema (HAE); the expected timing of initiation and design of the planned Phase 3 trials of STAR-0215; the potential best-in-class profile of STAR-0215, the potential therapeutic benefits of STAR-0215 as a treatment for HAE, the potential market impact of STAR-0215 as a treatment for HAE, including its potential to be the market leader, and our vision and goals for the STAR-0215 program; the potential best-in-class profile of STAR-0310 and the potential therapeutic benefits and potential attributes of STAR-0310 as a treatment for atopic dermatitis (AD); expectations regarding the timing of regulatory filings for STAR-0310; expectations regarding the timing of initiation and planned design of clinical trials for STAR-0310 in AD; expectations regarding the timing and nature of anticipated data from planned trials of STAR-0310; our goals and vision for STAR-0310; the potential commercial opportunity for STAR-0310 in AD and the likelihood that it can effectively compete in AD, assuming it is approved; the plans to develop STAR-0310 for additional indications and the timing of clinical trials for such potential indications; the expected growth and evolution of the AD market and comparisons of the AD market to analog markets; anticipated cash runway; and our corporate strategy and vision, including the goal to meet the unmet needs of patients with rare and niche allergic and immunological diseases. The use of words such as, but not limited to, "anticipate," "believe," "continue," "could," "estimate," "expect," "goals," "intend," "may," "might," "plan," "potential," "predict," "project," "should," "target," "will," "would," or "vision," and similar words expressions are intended to identify forward-looking statements. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, they are based on Astria's current beliefs, expectations and assumptions regarding the future of its business, future plans and strategies, future financial performance, results of pre-clinical and clinical results of the Astria's product candidates and other future conditions. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including risks and uncertainties: changes in applicable laws or regulations; the possibility that we may be adversely affected by other economic, business, and/or competitive factors; risks inherent in pharmaceutical research and development, such as: adverse results in our drug discovery, preclinical and clinical development activities, the risk that the results of preclinical studies may not be replicated in clinical trials, that the preliminary or interim results from clinical trials may not be indicative of the final results, that the results of early stage clinical trials, such as the results from the STAR-0215 Phase 1a clinical trial, may not be replicated in later stage clinical trials, including the ALPHA-STAR trial, the risk that we may not be able to enroll sufficient patients in our clinical trials on a timely basis, and the risk that any of our clinical trials may not commence, continue or be completed on time, or at all; decisions made by, and feedback received from, the U.S. Food and Drug Administration and other regulatory authorities on our regulatory and clinical trial submissions and other feedback from potential clinical trial sites, including investigational review boards at such sites, and other review bodies with respect to STAR-0215,STAR-0310, and any other future development candidates; our ability to manufacture sufficient quantities of drug substance and drug product for STAR-0215,STAR-0310, and any other future product candidates on a cost-effective and timely basis, and to develop dosages and formulation for STAR-0215, STAR- 0310, and any other future product candidates that are patient-friendly and competitive; our ability to develop biomarker and other assays, along with the testing protocols therefore; our ability to obtain, maintain and enforce intellectual property rights for STAR-0215,STAR-0310 and any other future product candidates; our potential dependence on collaboration partners; competition with respect to STAR-0215,STAR-0310, or any of our other future product candidates; the risk that survey results, modeling data and market research may not be accurate predictors of the commercial landscape for HAE, the ability of STAR-0215 to compete in HAE and the anticipated position and attributes of STAR-0215 in HAE based on clinical data to date, its preclinical profile, pharmacokinetic modeling, market research and other data; risks that any of our clinical trials of STAR-0310 may not commence, continue or be completed on time, or at all; risks that results of preclinical studies of STAR-0310 will not be replicated in clinical trials; risks with respect to the ability of STAR-0310 to compete in AD and the anticipated position and attributes of STAR-0310 in AD based on its preclinical profile; our ability to manage our cash usage and the possibility of unexpected cash expenditures; our ability to obtain necessary financing to conduct our planned activities and to manage unplanned cash requirements; the risks and uncertainties related to our ability to recognize the benefits of any additional acquisitions, licenses or similar transactions; and general economic and market conditions; as well as the risks and uncertainties discussed in the "Risk Factors" section of our Annual Report on Form 10-K for the period ended December 31, 2023 and in other filings that we may make with the Securities and Exchange Commission.

New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and uncertainties. Astria may not actually achieve the forecasts or expectations disclosed in our forward-looking statements, and investors and potential investors should not place undue reliance on Astria's forward-looking statements. Neither Astria, nor its affiliates, advisors or representatives, undertake any obligation to publicly update or revise any forward-looking statement, whether as result of new information, future events or otherwise, except as required by law. These forward-looking statements should not be relied upon as representing Astria's views as of any date subsequent to the date hereof.

2

Investment Highlights

Astria (Nasdaq: ATXS) is developing first-choice therapeutics for patients with allergic and immunological diseases

Our lead program, STAR-0215, is a monoclonal antibody inhibitor of plasma kallikrein for the preventative treatment of Hereditary Angioedema (HAE)

• STAR-0215has shown proof of concept as a Q3M and Q6M treatment, with a 90-96% reduction in monthly attack rate when dosed once or twice over six months, and favorable safety and tolerability profile
• Additional Phase 1b/2 data anticipated in H2 2024, Phase 3 trial expected to initiate Q1 2025

Our second program, STAR-0310, is a potential best-in-classOX40 program for AD with the goal to expand into additional indications. Anticipate IND submission by YE 2024 and Phase 1a initiation Q1 2025

Cash and cash equivalents of $369.9 million as of March 31, 2024, expected cash runway into mid-2027 based on current operating plan1

1. Current operating plan includes the development of STAR-0215 and STAR-0310, including (i) for STAR-0215, support for all program activities up to the completion of a planned Q3M Phase 3 pivotal trial, and (ii)	3
for STAR-0310, the anticipated submission of an IND and the initiation and completion of the planned Phase 1a clinical trial of healthy subjects (and any related anticipated milestone payments).

Hereditary Angioedema (HAE): A Rare, Disfiguring,

and Potentially Life-Threatening Disease

Rare genetic disorder characterized by severe, unpredictable, sometimes life-threatening swelling1

Affects<8,000 in the U.S. and <15,000 in Europe, 2,3,4

average age of onset is 11 years old5

• [During a laryngeal attack] it starts to be difficult to swallow and then your voice

changes, and then you have to make the

decision- am I going to go to the

hospital? Because certainly [doctors] would say you should- because you

never know if the rescue medication is
going to work.	"

1.1. Zuraw BL. N Engl J Med. 2008;359:1027-36.

2.2. Busse, P.J. et al. N Engl J Med. 2021; 132-150.

3.3. Lumry, W.R. Front Med. 2018; 5, 22.

4. Aygören-Pürsün, E. et.al. Orphanet j Rare Dis. 2018; 13:73.

5. Bork K, et al. Am J Med. 2006;119;267-274.4

6. Images obtained by haeimages.com

STAR-0215

Potential First-Choice Preventative Treatment in HAE

Validated Mechanism

Inhibition of plasma kallikrein leverages the same mechanism as market leader TAKHZYRO® (lanadelumab)

Goal: Reduce Disease and Treatment Burden to Normalize Lives

• Current treatments have high burden of administration or limited efficacy

Differentiated profile

• YTE extended half-life supports Q3 and Q6 month dosing
• Citrate-freeto reduce pain
• Trusted "non genetically modified" modality

Positive Proof-of-Concept Results in HAE Patients

• Support rapid, robust, and durable efficacy and the potential for dosing only 2 or 4 times per year

5

Opportunity for STAR-0215 to Lead the Market

2023 HAE Market1

2027 Estimated HAE Market1,2

HAE Treatment

Preventative

On-Demand

$2.8B$4.5B

The HAE market is expected to grow substantially by 2027,1,2 driven by:

• Patients being diagnosed earlier3
• More patients taking preventative treatments4
• Geographic expansion for currently available therapies5

STAR-0215well-positioned to become the

only therapy to achieve:

• Strong efficacy
• Rapid onset of action
• Trusted mechanism and modality
• Low treatment burden with administration 2 or 4x per year
• Low risk for injection pain

MARKET RESEARCH WITH HAE PATIENTS

INDICATES MARKET SHARE WILL COME FROM

ALL TREATMENT GROUPS

Injectables

Orals

On-Demand Only

1.	Company-reported sales (Takeda, CSL Behring, Pharming, BioCryst)	4.	Astria company research and analysis	6
2.	Analyst consensus forecasts compiled by Clarivate's Cortellis, Astria company research and analysis.	5.	Company-reported expectations (Takeda, CSL Behring, BioCryst)

3. Zanichelli A. Clin Transl Allergy. 2018: doi: 10.1186/s13601-018-0229-4

ALPHA-STAR Phase 1b/2 Initial Proof-of-Concept Results Include up to 6 Months of Follow-Up

Trial Design Schematic

	600 mg 600 mg
COHORT 3	8-weekrun-in
(n=6)		Day 1 Day 28
COHORT 2	8-weekrun-in600 mg	300 mg
(n=6)	Day 1	Day 84
COHORT 1	450 mg
8-weekrun-in

(n=4)	Day 1

SC Administration Patients are followed for 6 months after the last dose administered

• Ongoing Phase 1b/2 single and multiple dose proof-of-concept trial in adults with HAE Type 1 or Type 2
• Target enrollment has been achieved; all doses have been administered

SC = subcutaneous. Run-in period is at least 8 weeks (56 days) to measure baseline HAE attacks.
Initial data with data cut-off of 13-Mar-2024 for efficacy and safety data.​nI cohort 1, all 4 participants have completed 3 and 6 months of follow-up. In cohort 2, all 6 participants have completed 3 months
of follow-up and 3 of the 6 have completed 6 months of follow-up. In cohort 3, 4 of 6 participants have completed 3 months of follow-up and no participants have completed 6 months of follow-up. Figures	7
show baseline data for all participants and follow-up data for participants who completed 3 or 6 months of follow-up. Data cut-off of 8-Jan-2024 for PK and PD data.

STAR-0215 Monthly HAE Attack Reduction of 90-96%

through 3 and 6 Months

3 Change from Baseline (%)

Rate		2.70		Baseline
		2.30	0-3 Months Post-Treatment
		0-6 Months Post-Treatment
Attack
2	90%		1.82
HAE		96%
Monthly		92%	96%
1		90%
Mean
		0.27 0.23	0.12 0.12	0.18
	0
		Cohort 1	Cohort 2	Cohort 3

• Rapid and robust attack rate reduction up to 6 months after a single dose
• For the first 3 months following STAR- 0215 treatment, 50-67% of participants were attack-free
• Preliminary pharmacokinetic and pharmacodynamic data are consistent with Phase 1a data in healthy subjects

In cohort 1, all 4 participants have completed 3 and 6 months of follow-up. In cohort 2, all 6 participants have completed 3 months of follow-up and 3 of the 6 have completed 6 months of	8
follow-up. In cohort 3, 4 of 6 participants have completed 3 months of follow-up and no participants have completed 6 months of follow-up. Figures show baseline data for all participants

and follow-up data for participants who completed 3 or 6 months of follow-up.

STAR-0215 Reduced the Severity of HAE Attacks and Reduced

the Number of Attacks Requiring Rescue Medications

Through 3 and 6 Months

Mean Monthly HAE Attacks

2.5			Changes in Moderate and Severe	Change in Monthly Attacks
2.04		Attacks Per Month (Mean)	Requiring Rescue Medication

2												Baseline
						Moderate					0-3 Months Post-Treatment
							Attacks
										0-6 Months Post-Treatment
							Severe			2.06
1.5	92%		1.16
	1.16					HAE				1.59
							1.5		94%
1	96%		100%	0.63		Monthly	94%
									94%	95%
0.5					98%		100%	Mean		91%
	0.18 0.09		0.60	0	0.03	0.16	0
0	0.13			0.09	0.14	0.12 0.12	0.08

Cohort 1

Cohort 2

Cohort 3

• 92-100%decrease in moderate or severe attacks compared to baseline at 3 and 6 months

Cohort 1

Cohort 2

Cohort 3

• 91-95%fewer attacks required rescue medication after STAR-0215 compared to baseline at 3 and 6 months

Moderate and severe HAE attacks are shown.	9
HAE attacks requiring rescue medications are shown.

In cohort 1, all 4 participants have completed 3 and 6 months of follow-up. In cohort 2, all 6 participants have completed 3 months of follow-up and 3 of the 6 have completed 6 months of follow-up. In cohort 3, 4 of 6 participants have completed 3 months of follow-up and no participants have completed 6 months of follow-up. Figures show baseline data for all participants and follow-up data for participants who completed 3 or 6 months of follow-up.

STAR-0215 Was Well-Tolerated and Demonstrated a

Favorable Safety Profile

		Cohort 1 (N=4)	Cohort 2 (N=6)	Cohort 3 (N=6)	Total (N=16)
Treatment-Emergent Adverse	6	1	1	8
Events (TEAE)*
Contusion		3	-	-	3
Nasopharyngitis		1	1	1	3
Headache		2	-	-	2
Related TEAEs	-	1	1	2
Dizziness		-	1	-	1
Injection Site Rash		-	-	1	1
N with Serious Adverse Events		-	-	-	-
N who have discontinued due to		-	-	-	-
TEAE
* Shown are events that occurred in at least 2 participants.
One participant experienced mild dizziness on day 6 after the first dose in Cohort 2 and one participant experienced an injection site reaction (rash) 5 days after the second dose	10
in Cohort 3, lasting less than 1 day.
No injection site reactions of pain.