Merck KGaA and Mersana partner in potential $830m deal

Merck KGaA and Mersana Therapeutics (Mersana) have entered into a research collaboration and commercial licence agreement aimed at discovering novel antibody-drug conjugates (ADCs) for the treatment of cancer.

Under the terms of the agreement, Mersana will receive an upfront payment of $30m and will be eligible to receive up to $800m in potential milestone payments, as well as low double-digit percentage royalties.

The collaboration will see Mersana develop novel ADC product candidates for up to two targets, utilising its platform to combine Merck KGaA's proprietary antibodies.

ADCs combine the targeting properties of monoclonal antibodies with the cancer-killing capabilities of cytotoxic drugs and, unlike conventional chemotherapy, are designed to differentiate between healthy and diseased tissue.

Mersana’s proprietary Immunosynthen STING-agonist ADC platform generates systemically administered ADCs that locally activate STING signalling in both tumour-resident immune cells and antigen-expressing tumour cells, unlocking the anti-tumour potential of innate immune stimulation.

The company’s extensive preclinical data demonstrates the platform’s ability to enable highly targeted STING activation within both tumour cells and tumour resident myeloid cells while avoiding unwanted systemic effects.

Paul Lyne, head of research unit oncology at the healthcare business sector of Merck KGaA, said: “An approach that can directly target the tumour 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.”

Pre-clinical activities will be split between the two companies, with Merck KGaA solely responsible for all clinical development and potential commercialisation activities relating to any resulting product candidates.

Anna Protopapas, president and chief executive officer of Mersana, said: “We are pleased to be partnering with Merck KGaA to extend the reach of our Immunosynthen platform and bring novel new product candidates forward with the potential to benefit patients.”

In November last year, Merck KGaA announced its ambition to double R&D productivity in oncology, neurology and immunology, with the goal of delivering ‘more medicines to patients faster’.

The company outlined at the time that it expected to maintain the output of its internal discovery engine, while more than 50% of future launches would result from external co-development partnerships and strategic in-licensing of assets for further in-house development.