Mersana Therapeutics Presents Preclinical Data Highlighting Potential of XMT-2056 and XMT-1660 in Three Posters at Virtual 2021 AACR Annual Meeting

CAMBRIDGE, Mass., April 10, 2021 (GLOBE NEWSWIRE) -- 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, today presented preclinical data from XMT-1660, a B7-H4-targeted Dolasynthen antibody-drug conjugate (ADC), and XMT-2056, an Immunosynthen-based STING-agonist ADC at the Virtual 2021 American Association for Cancer Research Annual Meeting being held from April 10-15th.   

“The ability of Immunosynthen-based ADCs to activate the innate immune system via STING in tumor cells in addition to tumor-resident immune cells in a targeted manner could offer a significant therapeutic advantage over ADCs that modulate other immune activating pathways. These data demonstrate that XMT-2056 is highly differentiated from other innate immune activating approaches and has the anti-tumor activity and tolerability to support continued development of this novel STING-agonist ADC candidate,” said Timothy B. Lowinger, Ph.D., Chief Science and Technology Officer of Mersana Therapeutics. “Additionally, we presented data showing that XMT-1660 outperformed other B7-H4 ADCs in vivo. The inversely correlated expression of B7-H4 and PD-L1 in breast tumors suggests an opportunity for a B7-H4 Dolasynthen ADC to address patients poorly served by checkpoint inhibitors. We expect to complete IND-enabling studies and advance both XMT-1660 and XMT-2056 into the clinic in early 2022.”

“These encouraging data for both the Dolasynthen and Immunosynthen platforms demonstrate the scientific prowess of the Mersana research team and our commitment to discover and develop life-changing antibody-drug conjugates for patients fighting cancer,” said Anna Protopapas, President and Chief Executive Officer of Mersana Therapeutics.

Details of the posters are as follows:

Poster Title: XMT-1660, a B7-H4-targeted Dolasynthen antibody-drug conjugate for the treatment of breast cancer
Poster Number: 907
Session Category: Experimental and Molecular Therapeutics
Session Title: Antibody Technologies

These data show that B7-H4 is a promising target for a Dolasynthen ADC due to its expression and function. B7-H4 is expressed across multiple different tumor types with high unmet medical need, including breast, endometrial and ovarian. XMT-1660 demonstrated robust in vivo activity against multiple triple-negative breast cancer models, as well as an ER+/HER2- breast cancer model, all of which express B7-H4.