EMD Serono, Inc., a subsidiary of Merck KGaA, Darmstadt, Germany, and Mersana Therapeutics, Inc., Cambridge, Massachusetts, have agreed to collaboratively develop antibody-drug conjugates (ADCs). ADCs are composed of an antibody linked to cytotoxic drugs, whereby the antibody part specifically targets and delivers the cytotoxic drug to cancer cells, which could lead to higher drug levels at the tumor site.

Mersana and EMD Serono will leverage Mersana's Fleximer technology to generate ADCs for multiple undisclosed targets. Both parties have agreed to test a variety of ADCs by using Mersana's platform technologies, and several cytotoxic agents as conjugates. Under the agreement, EMD Serono will provide monoclonal antibodies to Mersana, which will generate the Fleximer-ADCs and conduct drug discovery and preclinical development activities. EMD Serono will be responsible for clinical development and commercialization of any products under an exclusive license from Mersana. In addition to an upfront payment, Mersana is eligible to receive milestones plus royalties on worldwide net sales of products. Further financial details are not being disclosed.

Mersana's Fleximer ADC technology is based on the company's proprietary biodegradable polymer system, known as Fleximer, and a wide variety of linkers that allow for the attachment of anti-tumor payloads to Fleximer. As an example, once loaded with drug(s), Fleximer is then attached through a stable linker that is different from the drug linker(s), to an antibody or antibody alternative to create a Fleximer-ADC. Mersana's proprietary payload platforms include Dolaflexin, an auristatin derivative; Vindeflexin, a vindesine derivative; and Cytoflexin, a tubulysin derivative.

Source: EMD Serono