German pharma company Merck is buying US biotech SpringWorks Therapeutics for $3.9B. SpringWorks makes medicines for cancer and rare diseases and is expected to give a boost to Merck's health-care division.

Merck KGaA has struck a deal to buy U.S. biotech company SpringWorks Therapeutics for an equity value of $3.9 billion to add rare cancer therapies ahead of expected revenue losses linked to expiring patents.

Germany’s Merck KGaA agreed to acquire U.S. biopharmaceutical company SpringWorks Therapeutics for around $3.9 billion, in a bid to expand its oncology and rare disease business.The German life-sciences and chemicals company said Monday that the deal seeks to strengthen its healthcare segment and to expand its presence in the U.