Merck KGaA of Germany's bid to acquire Switzerland's Serono has moved a step nearer after the European Commission gave its approval to the deal.

The Commission cleared the deal automatically after identifying no antitrust problems. Its counterpart in the USA also unanimously approved the merger at the end of October.

Merck agreed to buy the Bertarelli family's 64.5% controlling stake in Serono for 1,100 Swiss francs per share back in September, in a deal worth 10.6 billion euros ($13.5 billion), and the Darmstadt-based group noted that this particular transaction should be closed by early January.

After that, Merck will make a tender offer, under Swiss law, to the rest of Serono’s stockholders at the same price.

The German firm has also been buying Serono shares on the open market and has spent over 450 million euros on them. It also recently secured a 11.5 billion euro multi-currency term loan and revolving credit facility in order to finance the deal.

Once completed, the German firm's branded drugs business will be combined with Serono to create Merck-Serono Biopharmaceuticals which will have its headquarters in Geneva, and its US base in Boston. The new group will have pro forma sales of around 7.7 billion euros.