Merck & Co. agreed to buy respiratory drugmaker Verona Pharma Plc for around $10 billion as part of its ongoing search for ways to fill the Keytruda-sized hole that will emerge over the next few years.

Merck said on Wednesday it will acquire UK-based Verona Pharma for about $10 billion, gaining a promising respiratory treatment as it faces pressure to diversify beyond its blockbuster cancer drug Keytruda.

The move bolsters Merck’s lineup as it braces for the 2028 loss of patent exclusivity for blockbuster cancer drug Keytruda.