Balance Sheet Data (in thousands) (unaudited)

Adicet Reports First Quarter 2021 Financial Results and Provides Business Updates

Menlo Park, CA and Boston, MA - May 17, 2021 - Adicet Bio, Inc. (Nasdaq: ACET), a biotechnology company discovering and developing first-in-class allogeneic gamma delta T cell therapies for cancer and other diseases, today reported financial results for the first quarter ended March 31, 2021.

"The first quarter of 2021 has been highly productive for Adicet both on the financial and clinical fronts. The successful execution of our capital raise, and the initiation of the Phase 1 trial of our lead product candidate, ADI-001, being evaluated for the treatment of NHL, have put us in a strong position to continue to build upon our ongoing momentum through the rest of the year," said Chen Schor, President and Chief Executive Officer of Adicet Bio. "We look forward to reporting interim clinical data from the Phase 1 study of ADI-001 later this year as well as continuing to develop our pipeline of "off-the-shelf" gamma delta T cell product candidates for the treatment of solid and hematologic tumors."

First Quarter & Recent Business Updates:

Financial Results for First Quarter 2021:

About Adicet Bio, Inc.

Adicet Bio, Inc. is a biotechnology company discovering and developing allogeneic gamma delta T cell therapies for cancer and other diseases. Adicet is advancing a pipeline of "off-the-shelf" gamma delta T cells, engineered with chimeric antigen receptors and T cell receptor-like antibodies to enhance selective tumor targeting, facilitate innate and adaptive anti-tumor immune response, and improve persistence for durable activity in patients. For more information, please visit our website at http://www.adicetbio.com.

Forward-Looking Statements

This press release contains "forward-looking statements" of Adicet within the meaning of the Private Securities Litigation Reform Act of 1995 relating to business and operations of Adicet including, but not limited to, express or implied statements regarding preclinical and clinical development of Adicet's product candidates, including future plans or expectations for ADI-001 and ADI-002 and potential therapeutic effects of ADI-001 and ADI-002 the timing and outcome of discussions with FDA and other regulatory agencies, expectations regarding the design, implementation, timing, and success of its current and future clinical studies of ADI-001 and ADI-002 including whether they are pivotal or would support registration, expectations regarding its other CAR T cell therapy development activities, Adicet's growth as a company and the anticipated contribution of the members of its board of directors to its operations and progress, and its expectations regarding its uses of capital, expenses, future accumulated deficit and other first quarter 2021 financial results. Any forward-looking statements in this press release are based on management's current expectations and beliefs of future events, and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements, including without limitation, the effect of COVID-19 on Adicet's business and financial results, including with respect to disruptions to its clinical trials, business operations, and ability to raise additional capital; Adicet's ability to execute on its strategy; that positive results from a clinical study may not necessarily be predictive of the results of future or ongoing clinical studies; future clinical studies may fail to demonstrate adequate safety and efficacy of our product candidates, which would prevent, delay, or limit the scope of regulatory approval and commercialization; regulatory approval processes of the FDA and comparable foreign regulatory authorities are lengthy, time-consuming, and inherently unpredictable; regulatory developments in the United States and foreign countries;

Adicet's estimates regarding expenses, future revenue, and capital requirements; as well as those risks and uncertainties set forth in Adicet's most recent annual report on Form 10-K and subsequent filings with the Securities and Exchange Commission (SEC). For a discussion of these and other risks and uncertainties, and other important factors, any of which could cause Adicet's actual results to differ from those contained in the forward-looking statements, see the section entitled "Risk Factors" in Adicet's most recent annual report on Form 10-K and our periodic reports on Form 10-Q and Form 8-K filed with the SEC, as well as discussions of potential risks, uncertainties, and other important factors in Adicet's other filings with the SEC. All information in this press release is as of the date of the release, and Adicet undertakes no duty to update this information unless required by law.

Investor and Media Contacts

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Consolidated Statements of Operations and Comprehensive Loss

(in thousands, except share and per share amounts)