Merck KGaA is now the fourth Big Pharma to sign on to a collaboration with C4 Therapeutics.

Apparently, C4 Therapeutics' protein degradation tech brings all the Mercks to the yard. The Massachusetts biotech has signed on Merck KGaA in a $740 million biobucks partnership to find two degraders for cancer. 

Merck KGaA is offering $16 million upfront and $740 million in biobucks for the two degraders aimed at proteins that drive cancer growth. Merck will pay for C4’s discovery work and be responsible for future clinical development, according to Monday's announcement. C4 also stands to make mid single- to low double-digit royalties should any of the targets turn into marketed drugs. 

Paul Lyne, head of Merck KGaA’s oncology research unit, said the deal adds more depth to the company’s protein degradation investments. 

The deal comes less than three months after Merck & Co. inked a research partnershipwith C4 of its own, paying $10 million upfront and more than $600 million in biobucks for the smaller company to develop an exclusive degrader-antibody conjugate (DAC). The New Jersey Merck has the option to license three additional DACs, which would push the value of the deal to $2.5 billion. 

C4 has now inked collaborations with four Big Pharmas, with Biogen and Roche also tied up in collaborations with the company.