Merck buys Prometheus Biosciences for almost $11bn

Merck has agreed to buy Prometheus Biosciences for $10.8bn as the US drugmaker bolsters it pipeline ahead of the possible loss of exclusivity over its best-selling cancer drug later this decade.

The all-cash transaction for Prometheus — a San Diego-based biotech focusing on diseases caused by abnormal activity of the body’s immune system — is the latest sign of a rebound in mergers and acquisitions in the sector following a dip in activity last year.