The US Federal Trade Commission is asking for more information on the proposed merger of Pfizer and Allergan.

The companies insist that the so-called ‘second request’ was “fully anticipated as part of the regulatory process” and that they “continue to work cooperatively and expeditiously with the FTC in connection with its review”.

Pfizer and Allergan announced the $160-billion merger back in November. Under the plans, the companies will combine under Allergan, which will be renamed Pfizer, to create the world’s leading drugmaker by sales with headquarters in Ireland.

Pfizer says the merger will significantly enhance its innovative businesses through a growing revenue stream from Allergan’s “durable and innovative flagship brands”, as well as enhance its R&D capabilities in both new molecular entities and product-line extensions. 

But the deal’s completion remains subject to various closing conditions, including the expiration of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act, governmental and regulatory approvals in certain other jurisdictions, including the EU, necessary approvals from both Pfizer and Allergan shareholders, and the latter’s pending divestiture of its generics business to Teva. 

Nevertheless, the companies said they continue to expect the transaction to close in the second half of this year.