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Bolt Biotherapeutics Presents Preclinical Proof of Concept Data at American Association for Cancer Research (AACR) Conference

REDWOOD CITY, Calif., April 1, 2019 /PRNewswire/ -- Bolt Biotherapeutics, Inc., a biotechnology company focused on unleashing the power of the immune system to achieve anti-tumor immunity, today released positive preclinical proof of concept data on its promising Immune-Stimulating Antibody Conjugate (ISAC) platform. The data showed the potential of ISACs to eradicate tumors in animal models, which led to immunological memory of tumor-antigen positive and tumor-antigen negative tumors, suggestive of epitope spreading. These data were presented today at the American Association for Cancer Research (AACR) Conference in Atlanta, Georgia in a poster presentation titled "TLR7/8 immune-stimulating antibody conjugates elicit robust myeloid activation and durable anti-tumor immunity."

In contrast to traditional TLR agonists that require intratumoral administration, Bolt presented a series of in vivo studies demonstrating that its novel Boltbody™ ISACs can be delivered systemically and generate anti-tumor immunity in several different cancer models.  In human tumor models ranging in HER2 expression level, Boltbody ISAC treatment demonstrated significant anti-tumor efficacy against tumors that could not be controlled by the clinically-validated parental antibody, trastuzumab.  Furthermore, in a syngeneic tumor model, animals previously cleared of HER2 positive tumors by Boltbody ISAC treatment were challenged with a second tumor lacking expression of the HER2 tumor-antigen and were resistant to tumor growth.  In summary, the key preclinical achievements presented are:

  • Anti-tumor efficacy in trastuzumab refractory models
  • Immunological memory
  • Epitope spreading against tumors without HER2 antigen expression

"This is an exciting opportunity for Bolt to be able to share our novel technology for the first time.  We believe our Boltbody ISACs offer many unique benefits including the ability to achieve potent localized antitumor activity following systemic administration given the encouraging results observed by others with intratumoral delivery of TLR agonists in patients," stated David Dornan, Ph.D., senior vice president of research at Bolt Biotherapeutics. "We are advancing toward clinical assessment of our lead candidate as rapidly as possible."

"As a physician who has spent decades developing and understanding cancer immunotherapies, I was pleased to see that the Boltbody ISACs not only cleared tumors, but also generated immunological memory.  This indicates the potential for a patient's immune system to keep cancer from returning," stated Ed Engleman, M.D., Bolt founder and co-director of the Immunology and Immunotherapy Research Program at the Stanford Cancer Institute. "Boltbody ISACs demonstrate the potential to treat patients who are refractory to standard of care therapies and have not yet generated a robust anti-tumor immune response."

About Bolt Biotherapeutics' Immune-Stimulating Antibody Conjugate (ISAC) Platform Technology

The Boltbody platform consists of Immune-Stimulating Antibody Conjugates (ISAC) that harness the ability of TLR agonists to convert cold tumors into immunologically hot tumors (illuminating tumors to the immune system allowing them to be invaded by tumor killing cells). Boltbody ISACs have demonstrated the ability to eliminate tumors following systemic administration in preclinical models and have also led to the development of immunological memory.

About Bolt Biotherapeutics

Bolt Biotherapeutics, Inc., based in the San Francisco Bay Area, is a private biotechnology company developing Boltbody™ Immune-stimulating Antibody Conjugates (ISAC), a new class of immuno-oncology therapeutics.  The company is led by a team with extensive oncology drug discovery and development experience. Bolt was founded by Dr. Ed Engleman, and its platform is based on technology exclusively licensed from Stanford University.  The company is financed by world-class investors including Novo Holdings, Pivotal bioVenture Partners, Vivo Capital and Nan Fung Life Sciences. For more information about Bolt Biotherapeutics, please visit

Jennifer Williams
Cook Williams Communications, Inc.


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SOURCE Bolt Biotherapeutics, Inc.