After months of swirling rumours, Merck KGaA and SpringWorks Therapeutics have entered into a definitive agreement for Merck to acquire SpringWorks for an equity value of approximately US$3.9 B. Through the takeover, Merck picks up access to two cancer drugs approved in the US - Ogsiveo® (nirogacestat) for adults with desmoid tumours and Gomekli™ (mirdametinib) for adults and children with neurofibromatosis type 1 associated plexiform neurofibromas. The deal provides Merck with the opportunity to strengthen its focus on rare tumours, accelerate its growth and build its presence in the US.