Atreca Announces Publication in PNAS: “Mobilization of Innate and Adaptive Antitumor Immune Responses by the RNP-Targeting Antibody ATRC-101”

SAN CARLOS, Calif., May 04, 2022 (GLOBE NEWSWIRE) — Atreca, Inc. (Atreca) (NASDAQ: BCEL), a clinical-stage biotechnology company focused on developing novel therapeutics generated through a unique discovery platform based on interrogation of the active human immune response, today announced the peer-reviewed publication of preclinical data demonstrating how its lead product candidate, ATRC-101, activates the immune system and drives tumor destruction in a Proceedings of the National Academy of Sciences (PNAS) paper titled “Mobilization of Innate and Adaptive Antitumor Immune Responses by the RNP-Targeting Antibody ATRC-101.” “Immunotherapy approaches focusing on T cells have provided breakthroughs in treating solid tumors, but there remains an opportunity to drive anticancer immune responses via other immune cell types, particularly myeloid cells of the innate immune system,” said Tito A. Serafini, Ph.D., Chief Strategy Officer of Atreca. “The preclinical data published in PNAS indicate that ATRC-101 activates myeloid cells of the innate immune system via an RNA-containing tumor target that we discovered via our platform, leading eventually to an adaptive immune response that attacks tumor, which is a novel mechanism of action for an oncology therapeutic. Our data align well with how different RNA-containing targets drive similar innate and adaptive immune responses elsewhere in human biology. In March of this year, we presented results from our ongoing clinical trial of ATRC-101 demonstrating that anti-tumor activity is indeed associated with target expression, and we look forward to presenting additional clinical data later this year.” The PNAS publication details the discovery and preclinical development of ATRC-101, which was identified via a target-agnostic process evaluating antibodies produced by the plasmablast population of B cells in a patient experiencing an antitumor immune response during treatment with checkpoint inhibitor therapy. Immunohistochemistry studies demonstrated tumor-selective binding of ATRC-101 to multiple non-autologous tumor tissues, and biochemical analyses indicate that it targets an extracellular, tumor-specific ribonucleoprotein (RNP) complex. Robust antitumor activity and evidence of immune memory following rechallenge with fresh tumor cells were observed in syngeneic murine models, as well as an influx of conventional dendritic cell (cDC) type 1 cells in the blood within 24 hours of dosing, increased CD8+ T cells and natural killer (NK) cells in blood and tumor over time, decreased cDC type 2 cells in the blood, and decreased monocytic myeloid-derived suppressor cells in the tumor. Cellular stress, including that induced by chemotherapy, increased the amount of ATRC-101 target in tumor cells, and ATRC-101 combined with doxorubicin enhanced efficacy compared with either agent alone. “By leveraging the active human immune response to guide the identification of tumor-selective antibodies, an approach conceived by Atreca co-founder Dr. William Robinson, Professor of Immunology and Rheumatology at Stanford, Atreca’s novel approach to drug discovery has the potential to unlock a vast and diverse set of new cancer targets.” said Lawrence Steinman, M.D., Professor of Neurology and Neurological Sciences, Pediatrics, and Genetics, Stanford University Medical School. “In the case of ATRC-101, the approach delivered an antibody that appears to both bind a novel target and act via a novel mechanism, a remarkable achievement which we are pleased to have recognized in PNAS.” About Atreca, Inc. Atreca is a clinical-stage biopharmaceutical company developing novel antibody-based immunotherapeutics generated by its differentiated discovery platform. Atreca’s platform allows access to an unexplored landscape in oncology through the identification of unique antibody-target pairs generated by the human immune system during an active immune response against tumors. These antibodies provide the basis for first-in-class therapeutic candidates, such as our lead product candidate ATRC-101. A Phase 1b study evaluating ATRC-101 in multiple solid tumor cancers is currently enrolling patients. For more information on Atreca, please visit www.atreca.com.   Forward-Looking Statements This release contains forward-looking statements regarding our strategy and future plans, including statements regarding the development of ATRC-101 and our preclinical and clinical plans, including our plans to present additional ATRC-101 clinical data, the reports of our preclinical and clinical data, the potential of our discovery platform to identify new cancer targets, and the ability of our discovery platform to identify potentially valuable therapeutic antibodies. These forward-looking statements include, but are not limited to, statements about our plans, objectives, representations and contentions and are not historical facts and typically are identified by use of terms such as “potential” and “presenting” and similar words, although some forward-looking statements are expressed differently. Our actual results may differ materially from those indicated in these forward-looking statements due to risks and uncertainties related to the initiation, timing, progress and results of our research and development programs, preclinical studies, clinical trials, regulatory submissions, and other matters that are described in our most recent Annual Report on Form 10-K and Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (SEC) and available on the SEC’s website at www.sec.gov, including the risk factors set forth therein. Investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this release, and we undertake no obligation to update any forward-looking statement in this press release, except as required by law. Contacts Atreca, Inc.Herb CrossChief Financial [email protected]:Alex Gray, [email protected] Media:Julia Fuller, [email protected] Source: Atreca, Inc.