Atea Pharmaceuticals : Fourth Quarter 2021 Financial Results Conference Call Presentation

Fourth Quarter and Full Year 2021 Financial Results and Business Update

February 28, 2022

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. 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; planned 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 development process and the regulatory approval process, in particular for bemnifosbuvir combination product candidates and AT-752, our reliance on third parties over which we may not always have full control, competition from treatments for COVID-19 and hepatitis C and vaccines for COVID-19 and dengue, risks related to the COVID-19 pandemic on our business, and other important risks and uncertainties that are described in our most recent Annual Report on Form 10-K 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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Proprietary Platform Generates Deep Antiviral Pipeline

ssRNA VIRUS	THERAPEUTIC INDICATION	PRECLINICAL	PHASE 1	PHASE 2	PHASE 3
Coronaviridae	COVID-191	Bemnifosbuvir
(AT-527)
		Nucleotide*

	COVID-19	Bemnifosbuvir
	Nucleotide +
		Protease Inhibitor
Flaviviridae	Hepatitis C Virus	Bemnifosbuvir
	(HCV)2	Nucleotide
	Hepatitis C Virus	Ruzasvir**
	(HCV)
	(NS5A inhibitor)
	Dengue Virus	AT-752
		Nucleotide
Paramyxoviridae	Respiratory	Product
Syncytial Virus
Candidates
	(RSV)

HIGHLIGHTS

• Bemnifosbuvir (AT-527): preferred backbone for combination with protease inhibitor for COVID-19
• HCV and dengue programs advancing in Phase 2 trials in 2022
• Multiple value-driving milestones over next
  18-months across several indications
• $764.4 million in cash and cash equivalents as of 12/31/21
• Cash runway through 2025

*Bemnifosbuvir is a double prodrug nucleotide analog. ** Worldwide exclusive license for all uses from Merck. Bemnifosbuvir is the generic name for AT-527.

• 1. Bemnifosbuvir has been evaluated in Phase 2 results. In vitro combination studies are being conducted to generate data in support of clinical combination studies for COVID-19. 2. Bemnifosbuvir and Ruzasvir have been evaluated in Phase 2 studies and are anticipated to be developed as a combination for HCV.

Bemnifosbuvir

Combination Strategy for COVID-19

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COVID-19

Vision for Bemnifosbuvir in COVID-19: Preferred Backbone of Combination Therapy

Bemnifosbuvir (AT-527) Addresses Key Challenges of COVID-19

• Oral nucleotide with antiviral activity across SARS-CoV-2 variants of concern/interest

• Targets viral RNA polymerase, highly conserved enzyme critical to viral replication

bemnifosbuvir

• Unique mechanism with dual targets creating high barrier to resistance:

- NiRAN inhibition	Nsp12 Functional Domains
SARS-Cov-2

• Chain termination (RdRp) w/o introducing mutations in viral genome

N -		NiRAN		RdRp	- C

• Non-mutagenic in mammalian cells in nonclinical studies and no effect on reproduction and non-teratogenic
• Rapid & sustained antiviral activity demonstrated in Ph 2 in high-risk patients

51

249

366

932

RdRp = RNA-dependentRNA polymerase

NiRAN = Nidovirus RdRp-Associated

Nucleotidyltransferase

Nucleos(t)ide class: Established therapeutics as the backbone of oral

combination treatments for many RNA viral diseases

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