Low rate of COVID-19 infection observed in vaccinated, durably chimeric patients off immunosuppression No evidence of acute kidney injury or impaired renal function in FCR001-treated patients with COVID-19 infection No patients lost chimerism as a result of COVID-19 vaccination or infection BOSTON and LOUISVILLE, Ky., April 06, 2022 (GLOBE NEWSWIRE) — Talaris Therapeutics, Inc. (Nasdaq: TALS), a late-clinical stage cell therapy company developing therapies with the potential to transform the standard of care in solid organ transplantation and severe immune and blood disorders, today shared new data on COVID-19 outcomes among living donor kidney transplant (LDKT) patients treated in the Company’s Phase 2 trial of investigational cell therapy product FCR001 (NCT00497926). The data were presented in a poster at the 2022 Cutting Edge of Transplantation (CEoT) meeting organized by the American Society of Transplantation. As previously reported, 26 of 37 LDKT recipients of FCR001 from the Company’s Phase 2 study achieved durable chimerism and were able to discontinue and remain off all IS for the duration of follow-up, with a median follow-up of over six years. A retrospective chart review of patients in the Phase 2 study was conducted by researchers at Northwestern University, who examined COVID-19 infection rates, effects of COVID-19 infection, and evidence of antibody response to vaccination. Of the 28 patients for whom data were available, 23 were durably chimeric and all of these patients were able to discontinue chronic immunosuppression (IS). The remaining 5 patients were not durably chimeric and remained on chronic IS. Of the 23 durably chimeric patients off chronic IS, 18 were vaccinated, of whom 2 (11%) tested positive for COVID-19. None of these 18 patients lost chimerism or had renal dysfunction as a result of their COVID-19 vaccination. Among the remaining 5 patients who were off all chronic IS but were unvaccinated, 3 (60%) tested positive for COVID-19. Among the 5 patients who remained on chronic IS, 4 of whom were vaccinated, 2 (40%) tested positive for COVID-19. COVID-19 infection did not lead to reduction in renal function for the FCR-treated patients. None of the COVID-19-infected patients were hospitalized or developed severe disease. Additionally, post-vaccination antibody testing had been performed on 4 patients (3 durably chimeric, 1 nonchimeric). These data showed that all 4 patients produced measurable antibody responses to COVID-19 vaccination. “Based on published literature*, kidney transplant recipients are at increased risk of COVID-19-related complications in part because the use of chronic immunosuppression often impairs the immune system’s ability to fight viral infection or respond to vaccination. We were encouraged to see, among patients who were tolerized with FCR001 in our Phase 2 study, evidence of immunocompetence, both in the mild disease course experienced by those infected with COVID-19 and in the generation of antibodies post-vaccination,” said Suzanne Ildstad, M.D., Chief Scientific Officer of Talaris. “The low rate of COVID-19 infection in the patients who were off immunosuppression and fully vaccinated is also intriguing. The study’s small sample size means it’s difficult to draw larger conclusions, but given the unique nature of this cohort of patients, we believe it to be a valuable contribution to the evolving understanding of how COVID-19 impacts transplant recipients.” The poster, entitled “Experience with COVID-19 Infection and Vaccination in Combined Kidney/HSCT,” is available here. About Talaris TherapeuticsTalaris Therapeutics, Inc. is a late-clinical stage cell therapy company developing therapies with the potential to transform the standard of care in solid organ transplantation and severe immune and blood disorders. Talaris maintains corporate offices in Boston, MA, its cell processing facility in Louisville, KY, and additional research operations in Houston, TX. Cautionary Note Regarding Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, implied and express statements regarding Talaris Therapeutics, Inc.’s (“Talaris,” the “Company,” “we,” or “our”) strategy, business plans and focus; the progress and timing of the preclinical and clinical development of Talaris’ programs, including FCR001 and FCR002, as well as expectations around timing and completion of clinical trial enrollment; expectations regarding the timing and data from the planned clinical update of FREEDOM-1, FREEDOM-2 or FREEDOM-3, including upcoming milestones and therapeutic effects; and expectations regarding Talaris’ use of capital, expenses and other financial results during 2021 and in the future. The words “may,” “might,” “will,” “could,” “would,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,” “expect,” “estimate,” “seek,” “predict,” “future,” “project,” “potential,” “continue,” “target” or the negative of these terms and similar words or expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements in this press release are based on management’s current expectations and beliefs and are subject to a number of risks, uncertainties and important factors that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained in this press release, including, without limitation, risks associated with: the impact of COVID-19 on countries or regions in which the Company has operations or does business, as well as on the timing and anticipated timing and results of its clinical trials, strategy and future operations, including the expected timing and results from FREEDOM-1, FREEDOM-2 and FREEDOM-3, the planned initiation and timing of IND-enabling studies of FCR001 and FCR002 in deceased donor transplants and the announcement of any additional indications for FCR001; the risk that the results of Talaris’ clinical trials, including the early data from the FREEDOM-1 study, may not be predictive of future results in connection with future clinical trials; the Company’s expectations regarding the potential urinary biomarker of immune quiescence, the Company’s ability to successfully demonstrate the safety and efficacy of its drug candidates; the timing and outcome of Talaris’ planned interactions with regulatory authorities; and obtaining, maintaining and protecting its intellectual property. These and other risks and uncertainties are described in greater detail in the section entitled “Risk Factors” in the Company’s Annual Report on Form 10-K for the quarter and year ended December 31, 2021, as well as any subsequent filings with the Securities and Exchange Commission. In addition, any forward-looking statements represent Talaris’ views only as of today and should not be relied upon as representing our views as of any subsequent date. Talaris explicitly disclaims any obligation to update any forward-looking statements. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements. *Grupper et al Transplantation Proceedings (2022); Kremer et al Am J Transplant (2021); Caillard and Thaunat Nature Reviews Nephrology (2021) Media ContactLisa RaffenspergerTen Bridge Communicationslisa@tenbridgecommunications.com(617) 903-8783 Investor ContactChris BrinzeyICR Westwickechris.brinzey@westwicke.com(339) 970-2843