Merck will buy UK-based Verona Pharma for about $10 billion, the companies said on Wednesday, strengthening the U.S. drugmaker's respiratory treatments as part of efforts to reduce dependence on its blockbuster cancer treatment.

Merck said it will buy Verona Pharma for $10 billion to bolster its lung-disease business and help replace the expected loss of revenue once Keytruda patent protection lapses.

The deal gives Merck control of Verona’s Ohtuvayre, a newly approved treatment for chronic obstructive pulmonary disease