Achilles Therapeutics : Corporate Presentation – January 2023

Achilles Therapeutics

Targeting Clonal Neoantigens to Treat Solid Tumors with AI-Powered Precision Cell Therapy

January 2023

Non-Confidential	© Achilles Therapeutics plc 2023

Forward-Looking Statements / Disclaimers

This presentation contains express or implied forward-looking statements that are based on our management's belief and assumptions and on information currently available to our management. Although we believe that the expectations reflected in these forward-looking statements are reasonable, these statements relate to future events or our future operational or financial performance, and involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by these forward-looking statements.

In some cases, you can identify forward-looking statements by terminology such as "may," "should," "expects," "intends," "plans," "anticipates," "believes," "estimates," "predicts," "potential," "continue," or the negative of these terms or other comparable terminology. These statements are only predictions. You should not place undue reliance on forward-looking statements because they involve known and unknown risks, uncertainties, and other facts, which are, in some cases, beyond our control and which could materially affect results. If one or more of these risks or uncertainties occur, or if our underlying assumptions prove to be incorrect, actual events or results may vary significantly from those implied or projected by the forward-looking statements. No forward-looking statement is a guarantee of future performance. You should read this presentation and the documents that we reference in this presentation completely and with the understanding that our actual future results may be materially different from any future results expressed or implied by these forward-looking statements.

The forward-looking statements in this presentation represent our views as of the date of this presentation. We anticipate that subsequent events and developments will cause our views to change. However, while we may elect to update these forward-looking statements at some point in the future, we have no current intention of doing so except to the extent required by applicable law. You should therefore not rely on these forward-looking statements as representing our views as of any date subsequent to the date of this presentation. This presentation also contains estimates, projections and other information concerning our industry, our business and the markets for our product candidates. Information that is based on estimates, forecasts, projections, market research or similar methodologies is inherently subject to uncertainties and actual events, or circumstances may differ materially from events and circumstances that are assumed in this information. Unless otherwise expressly stated, we obtained this industry, business, market, and other data from our own internal estimates and research as well as from reports, research, surveys, studies, and similar data prepared by market research firms and other third parties, industry, medical and general publications, government data and similar sources. While we are not aware of any misstatements regarding any third-party information presented in this presentation, their estimates, in particular, as they relate to projections, involve numerous assumptions, are subject to risks and uncertainties and are subject to change based on various factors.

Certain graphics within were created with BioRender.com.

Non-Confidential	© Achilles Therapeutics plc 2023	1

Clinical-stage precision targeting for solid tumors using clonal neoantigen-reactive T cells (cNeT)

Transforming the treatment of solid tumors with precision T cell therapy by:

• targeting clonal neoantigens present on all cancer cells
• linking mechanism of action and potency with our translational science platform

CD4+

CD8+

Cancer

Clonal Cell

NeoAg

Global Headquarters	U.S. Headquarters
London, UK	Philadelphia, PA

Founded	Nasdaq IPO	Early PoC
2016	2021	2022

Non-Confidential	© Achilles Therapeutics plc 2023	2

Clinical-stage precision targeting for solid tumors using clonal neoantigen-reactive T cells (cNeT)

Emerging PoC for cNeT in NSCLC

Durable disease control achieved with cNeT monotherapy through 12 weeks

71% (5/7) NSCLC patients (including 1 PR and 4 SDs); encouraging safety and tolerability

Targeting clonal neoantigens: a novel class of cancer target present on all tumor cells

Developed a proprietary patented AI platform (PELEUS®) validated on real world patient data (TRACERx)

Controlled precision therapy

Scientific platform that can quantify, characterize and track the tumour reactive component to deconvolute mechanism of action, define potency and drive process improvements

Near-term clinical milestones

Clinical and translational updates in 2023: 15-20 new patients across NSCLC (CHIRON) monotherapy and melanoma (THETIS) monotherapy and in combination with check-point inhibitor (anti-PD-1)

Strong cash position

Cash runway of £161M* as of September 30, 2022 supports all planned operations into mid-2025

Non-Confidential	© Achilles Therapeutics plc 2023	* £1.000 = $1.116 for 9/30/2022 reporting of GBP balances in USD	3

Experienced leadership with decades in cell therapy drug development

Robert Coutts

CFO

Shree Patel

EVP, Patient Supply

Operations

Sergio Quezada

CSO

Iraj Ali

CEO

Jim Taylor

CBO

Karl Peggs

CMO

Daniel Hood

General Counsel

Ed Samuel

EVP, Technical

Operations

Non-Confidential	© Achilles Therapeutics plc 2023	4