French drugmaker Sanofi-Aventis has agreed to buy US biotech group Genzyme with a improved cash offer the equivalent of almost 14.9 billion euros.
It will also make additional payments based on the success of Genzyme’s drugs.
The acquisition comes nine months after it was first proposed and the deal should increase Sanofi’s earnings through Genzyme’s treatments for rare diseases.
The value of the extra payments will depend on Genzyme’s experimental multiple sclerosis drug Lemtrada and production of two other medicines.
It is the second-biggest deal in biotech history and will help Sanofi offset declining revenue from drugs that have lost, or are going to lose, patent protection, which means competitors can make cheaper so-called ‘generic’ versions.
Shares in Sanofi rose as investors welcomed the boost to earnings.