Germany's 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 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.

KEY TAKEAWAYS German drug company Merck KGaA said Monday it has struck a deal to buy U.S. biotech firm SpringWorks Therapeutics for around $3.9 billion, expanding its portfolio of rare disease and cancer treatments.