Pfizer to buy Seagen for about $43 billion

Pfizer Inc said on Monday it would buy Seagen Inc for about $43 billion to expand its portfolio of cancer treatments.

Pfizer will pay $229 in cash per Seagen share, a 32.7% premium to Friday's closing price. Shares of Seagen were up 23% before the bell.

Seagen expects to generate about $2.2 billion of revenue in 2023.