Atea Pharmaceuticals : First Quarter 2024 Financial Results Conference Call Presentation

First Quarter Results and Business Update

May 14, 2024

NASDAQ: AVIR

June 2020

DISCLAIMERS

Forward-Looking Statements

This presentation contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, they are based on our current beliefs, expectations and assumptions regarding the future of our business, future plans and strategies, our clinical results and other future conditions including without limitation the future of the COVID-19 and HCV landscapes and related commercial market opportunities. All statements other than statements of historical facts contained in this presentation are forward-looking statements, including statements by Atea Pharmaceuticals, Inc. (the "Company") regarding future results of operations and financial position, including our anticipated cash runway; business strategy; current and prospective product candidates; anticipated milestone events; potential benefits of our product candidates and market opportunity; clinical trials, including, without limitation, anticipated initiation, enrollment, regulatory submission and data readout timelines; preclinical activities; product approvals; manufacturing availability; degree of market acceptance of any products that may be approved; research and development costs; current and prospective collaborations; and prospects and opportunities for investors. In some cases, you can identify forward-looking statements by terms such as "may," "will," "should," "expects," "plans," "anticipates," "could," "intends," "targets," "projects," "contemplates," "believes," "estimates," "predicts," "potential" or "continue" or the negative of these terms or other similar expressions.

The information in this presentation, including without limitation the forward-looking statements contained herein, represent our views as of the date of this presentation. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any anticipated results, performance or achievements expressed or implied by the forward-looking statements. Risks and uncertainties that may cause actual results to differ materially include uncertainties inherent in the drug discovery and development process and the regulatory submission or approval process, unexpected or unfavorable safety or efficacy data or results observed during clinical trials or in data readouts; delays in or disruptions to clinical trials or our business; our reliance on third parties over which we may not always have full control, our ability to manufacture sufficient commercial product, competition from authorized and approved treatments for COVID-19 and hepatitis C, risks related to the continued evolution of COVID-19, and other important risks and uncertainties that are described in our Annual Report on Form 10-K filed for the year ended December 31, 2023 and our most recent quarterly report on Form 10-Q filed with the Securities and Exchange Commission ("SEC") and our other filings with the SEC. New risk factors and uncertainties may emerge from time to time, and it is not possible to predict all risk factors and uncertainties. Accordingly, you are cautioned not to place undue reliance on these forward-looking statements.

Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements.

Industry Information

Market data and industry information used throughout this presentation are based on management's knowledge of the industry and the good faith estimates of management. We also relied, to the extent available, upon management's review of independent industry surveys and publications and other publicly available information prepared by a number of third-party sources. All of the market data and industry information used in this presentation involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. Although we believe that these sources are reliable, we cannot guarantee the accuracy or completeness of this information, and we have not independently verified this information. While we believe the estimated market position, market opportunity and market size information included in this presentation are generally reliable, such information, which is derived in part from management's estimates and beliefs, is inherently uncertain and imprecise. No representations or warranties are made by the Company or any of its affiliates as to the accuracy of any such statements or projections. Projections, assumptions and estimates of our future performance and the future performance of the industry in which we operate are necessarily subject to a high degree of uncertainty and risk due

to a variety of factors, including those described above. These and other factors could cause results to differ materially from those expressed in our estimates and beliefs and in the estimates prepared by independent parties.

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Significant Near-term Clinical Milestones in 2024

Fully Funded Through Key Inflection Points

COVID-19 - Global Phase 3 SUNRISE-3 Trial

Full enrollment achieved	Topline
with 2,221 patients in
results
monotherapy cohort, 74
2H'24
in combination cohort
Mar'24

2024

	Reported 98% SVR4 rate	Preclinical &	Fixed	Ph 2 complete
	new Ph 2	dose tablet
	for lead-in cohort of 60	SVR12 results
	patients & resumed	efficacy data	selection	2H'24
HCV	presentations at	Mid'24
enrollment Jan'24
		EASL Jun'24

HCV - Global Phase 2 Study

NDA submission target

YE'24

2025

Ph 3 Initiation target

YE'24

$541.5 M	Cash, cash equivalents & marketable securities at 3/31/24
Cash runway now anticipated into 2027

3

HEPATITIS C

Program Update:

Potential Best-in-Class

Pan-Genotypic Regimen

• Phase 2 Open Label Study of Bemnifosbuvir + Ruzasvir

HCV

Continues to be a healthcare crisis in US

Recognized ongoing unmet needs by US healthcare providers

UNMET MEDICAL NEED in US:

>2M estimated to have HCV

New chronic HCV cases (~100,000) annually exceed cures

Best-in-Class Target Profile - Bemnifosbuvir + Ruzasvir

Bemnifosbuvir is the most potent nucleotide inhibitor for HCV1 and ruzasvir is a highly potent NS5A inhibitor2

• Short 8-week treatment with lower daily pill burden
• Potential for fewer side effects, low risk for drug-drug interactions and no food effect
• Protease inhibitor-free treatment

Global Market Opportunity:

>$3B	Primarily	No
2	competitors
net sales in	product	in clinical
2023	development
market

5	1.	PLoS ONE 15(1):e0227104 https://doi.org/10.1371/journal.pone.0227104
2.	Journal of Viral Hepatitis, 2019, September:26 (9); 1127-1138.

HEPATITIS C

Bemnifosbuvir (BEM) + Ruzasvir (RZR) Target Product Profile

Profile		BEM+RZR	MAVYRET®	EPCLUSA®
	Non-Cirrhotic	8 Weeks	8 Weeks	12 Weeks
Treatment Duration	Compensated Cirrhosis	8 Weeks	8 Weeks	12 Weeks
	Decompensated Cirrhosis	12 Weeks		12 Weeks +
	(No RBV)		RBV

Short Duration

Protease-Inhibitor Free

Low Potential for Drug-Drug Interactions

No Food Effect

• RBV= Ribavirin

HEPATITIS C

US HCV Market: Epclusa® & Mavyret®

Potential US HCV

Market Value

	2022	2023
# of Patients (NRxs) Treated1	93,452	98,412
Total US HCV Market	$1,599M	$1,518M
Net Revenues2
Net Revenues Per	$17,110	$15,425
Patient Treated
Epclusa®* NRx Market Share1	53%	54%
Mavyret® NRx Market Share1	43%	42%

Market demand grew ~5% 2023

2023

$1.5B

US Net Revenues

for DAA

98,412

• of US Patients Treated (NRxs)

Stable

market share

Treatment of all	>$20B
current chronic
HCV patients	Potential Market Value**
	>2M
	Chronic US HCV
	Prevalence

FUTURE DRIVERS

• US government initiatives
• Optimal product profile
• Removal of HCV prescribing barriers by payors

*Epclusa includes both brand and authorized generics	** Assumes treatment of all currently chronically infected HCV
patients of 2.2M at $10,000 Net Revenue/Patient

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1. IQVIA NPA Data 2. Net Revenues from Gilead and Abbvie's full-year 2023 earnings press release

HEPATITIS C

Phase 2 Open Label Study of Bemnifosbuvir + Ruzasvir in HCV Patients

Study Design: Open label combination

N= up to 280: including lead-in cohort

Patient Population:

• HCV-infectedpatients, including compensated cirrhosis
• Direct-actingantiviral naïve
• All genotypes

60 Patient Lead-in Cohort:

• Safety and tolerability

• Sustained virologic response (SVR) at Week 4 post-treatment (SVR4)

Bemnifosbuvir (BEM) 550 mg QD	Enrollment
Ruzasvir (RZR) 180 mg QD	Ongoing

8 weeks dosing w/combination

Primary Endpoints:

• SVR at Week 12 post-treatment (SVR12)
• Safety

Other Endpoints:

• Virologic failure
• SVR at Week 24 post-treatment (SVR24)
• Resistance

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HEPATITIS C

New Data: Final Results 98% SVR4 Post-Treatment

Phase 2 Open Label Study of Bemnifosbuvir + Ruzasvir Lead-in Cohort

100

	90		100%	98%
	90%
	80
(%)	70
<>	60
50
Patients	40
	30
	20
	10
	54/60	60/60	58/59*
	0
		Wk 4	Wk 8	SVR4
			Study Visit

LLOQ=Lower limit of quantification *Does not include 1 subject who did not attend the SVR4 visit.

BEM + RZR with short 8-week treatment

Final results for lead-in cohort: 98% SVR4

• 1 genotype 2 subject with poor

adherence did not achieve SVR4

(lower pill consumption and inadequate PK drug levels)

9

HEPATITIS C

On-Treatment Viral Kinetics - Individual Patient Data (n=60)

Phase 2 Open Label Study of Bemnifosbuvir + Ruzasvir Lead-in Cohort

• Regardless of baseline viral load, all patients (n=60) near or below LLOQ by Week 4

• BEM + RZR viral kinetics compare favorably to Mavyret1, the only approved 8-week treatment for HCV

• Very rapid kinetics across genotypes support an 8-week regimen

LLOQ=Lower limit of quantification

1. Sarrazin et.al; Presented at ID Week 2018

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