Achilles Therapeutics Announces Filing of Registration Statement for Proposed Initial Public Offering in the United States

Achilles Therapeutics Announces Filing of Registration Statement for Proposed Initial Public Offering in the United States

London, UK 1 March 2021 – Achilles Therapeutics plc (“Achilles” or the “Company”), a clinical-stage biopharmaceutical company developing precision T cell therapies to treat solid tumors, today announced it has filed a registration statement on Form F-1 (the “Registration Statement”) with the U.S. Securities and Exchange Commission (the “SEC”) relating to a proposed initial public offering (“IPO”) in the United States of its American Depositary Shares (“ADSs”), each representing one ordinary share of the Company. All ADSs to be sold in the proposed IPO will be offered by Achilles. The number of ADSs to be sold and the pricing terms for the proposed IPO have not yet been determined.

J.P. Morgan, BofA Securities and Piper Sandler are expected to act as joint book-running managers for the offering. Chardan, Oppenheimer & Co, and Kempen & Co are expected to act as co-managers.

The Registration Statement relating to the securities has been filed with the SEC but has not yet become effective. These securities may not be sold, nor may offers be accepted, prior to the registration statement becoming effective. This press release shall not constitute an offer to sell or the solicitation of an offer to buy, nor shall there be any sale of, these securities in any state or jurisdiction in which such offer, solicitation, or sale would be unlawful prior to registration or qualification of these securities under the securities laws of any such state or jurisdiction.

The securities referred to in this announcement are to be offered only by means of a prospectus. When available, copies of the preliminary prospectus relating to and describing the terms of the proposed IPO can be obtained from the following sources:

• J.P. Morgan Securities LLC, Attention Equity Syndicate Desk, 383 Madison Avenue, New York, New York 10179, or via email: prospectuseq_fi@jpmchase.com;

• BofA Securities, Attention: Prospectus Department, NC1-004-03-43, 200 North College Street, 3rd Floor, Charlotte, NC 28255-0001, or via email: dg.prospectus_requests@bofa.com; or

• Piper Sandler & Co., Attention: Prospectus Department, 800 Nicollet Mall, J12S03, Minneapolis, MN 55402, by telephone: (800) 747-3924, or via email: prospectus@psc.com.

Achilles has applied to list its ADSs on The Nasdaq Global Market under the symbol “ACHL.”

About Achilles Therapeutics

Achilles is a clinical-stage, biopharmaceutical company developing precision T cell therapies targeting clonal neoantigens: protein markers unique to the individual that are expressed on the surface of every cancer cell. The Company has two ongoing Phase I/IIa trials, the CHIRON trial in patients with advanced non-small cell lung cancer (NSCLC) and the THETIS trial in patients with recurrent or metastatic melanoma. Achilles uses DNA sequencing data from each patient, together with its proprietary PELEUS™ bioinformatics platform, to identify clonal neoantigens specific to that patient, and then develop precision T cell-based product candidates specifically targeting those clonal neoantigens.

Further information:

Lee M. Stern – VP, IR & External Communications
+1 (332) 373-2634
l.stern@achillestx.com

Consilium Strategic Communications
Mary-Jane Elliott, Sukaina Virji, Melissa Gardiner
+44 (0) 203 709 5000
achillestx@consilium-comms.com