Merck and Mersana Therapeutics to co-develop new immunostimulatory ADCs

Merck has announced a collaboration with US-based Mersana Therapeutics to discover new antibody-drug conjugates (ADCs) by leveraging the latter’s proprietary Immunosynthen STING-agonist ADC platform.

The collaboration complements Merck’s internal know-how and in-house antibody-drug conjugate method.

As part of the agreement, Mersana Therapeutics will develop new antibody-drug conjugate product candidates against up to two targets using the company’s Immunosynthen platform to conjugate proprietary antibodies from Merck.

Under the research collaboration and commercial license agreement, Merck will acquire exclusive license to Mersana Therapeutics’ Immunosynthen platform. Mersana Therapeutics will receive an upfront payment of $30 million, up to $800 million in potential development, regulatory and commercial milestones, as well as royalties on net sales across the globe.

Paul Lyne — Merck Oncology Research Unit Head said: “Building on our deep expertise and portfolio of two clinical and nine preclinical assets in the ADC space, we are focused on the discovery of next-generation state-of-the-art ADC drugs.

“An approach that can directly target the tumor microenvironment with an immunomodulatory ADC has the potential to bring the benefits of this immunotherapy to a broader group of patients.

“This collaboration with Mersana to design novel immunostimulatory ADCs that can harness the potential of the STING pathway is an ideal complement to our innovation in this area.”

The Immunosynthen platform generates systemically administered ADCs that locally activate STING signaling in both tumor-resident immune cells and in antigen-expressing tumor cells, unlocking the anti-tumor potential of innate immune stimulation.

Anna Protopapas — Mersana Therapeutics President and CEO said: “We are pleased to be partnering with Merck in a collaboration designed to extend the reach of our Immunosynthen platform and bring novel new product candidates forward with the potential to benefit patients.”

Preclinical data has demonstrated Immunosynthen’s efficacy and effectiveness in activating STING within both tumor cells and tumor resident myeloid cells.

The STING pathway generates innate immune response leading to anti-tumor activity and immunological memory.