On March 10, 2021 Mersana Therapeutics, Inc. (NASDAQ:MRSN), a clinical-stage biopharmaceutical company focused on discovering and developing a pipeline of antibody-drug conjugates (ADCs) targeting cancers in areas of high unmet medical need, reported that it will present data in three poster sessions at the upcoming Virtual 2021 American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting being held from April 9-14, 2021 (Press release, Mersana Therapeutics, MAR 10, 2021, View Source [SID1234576402]).

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Details of the poster displays are as follows:

Poster Title: XMT-1660, a B7-H4-targeted Dolasynthen antibody-drug conjugate for the treatment of breast cancer
Abstract Number: 907
Abstract Summary: These data indicate that XMT-1660, a DAR 6 Dolasynthen ADC, exhibited a superior preclinical profile relative to DAR 2 and DAR 12 ADCs and thus support the clinical development of XMT-1660 for the treatment of B7-H4-expressing tumors such as breast cancer and other cancers. These results demonstrate the importance of DAR-ranging studies to identify the optimal ADC for a given target.
Date: April 10, 2021
Session Category: Experimental and Molecular Therapeutics
Session Title: Antibody Technologies

Poster Title: XMT-2056, a well-tolerated, Immunosynthen-based STING-agonist antibody-drug conjugate which induces anti-tumor immune activity
Abstract Number: 1738
Abstract Summary: These data demonstrate that XMT-2056 induced robust anti-tumor immune activity, with only minimal increases in systemic cytokine levels, and exhibited significant benefit over the benchmark IV administered free STING-agonist in mice. Additional studies demonstrate that Immunosynthen ADCs activate the STING pathway in both tumor-resident immune cells and tumor cells, offering a potential advantage over ADCs that modulate other innate immune activating pathways. XMT-2056 was well-tolerated in non-human primates at significantly higher exposure levels than those required for anti-tumor activity in mice and exhibited favorable pharmacokinetics after repeat doses. Together these data support the clinical development of XMT-2056.
Date: April 10, 2021
Session Category: Immunology
Session Title: Immunomodulatory Agents and Interventions

Poster Title: Tumor cell-intrinsic STING pathway activation leads to robust induction of Type III Interferons and contributes to the anti-tumor activity elicited by STING agonism
Abstract Number: 1773
Abstract Summary: The STING pathway induces anti-tumor immunity by upregulating an interferon response within the tumor microenvironment. Data presented in this study demonstrate that cancer cells activate a Type III interferon response downstream of STING pathway activation. Blocking Type III IFNs with neutralizing antibodies in cancer cell:immune cell co-cultures inhibits the production of key cytokines and cancer cell killing induced by STING-agonist ADC treatment. These results indicate that the Type III IFN response in cancer cells plays an important role in the anti-tumor activity induced by STING-agonist ADCs.
Date: April 10, 2021
Session Category: Immunology
Session Title: Innate Immunity to Tumors