Pharmaceutical company Alkermes Inc. (ALKS) on Friday completed its merger with Elan Drug Technologies, a drug formulation and manufacturing subsidiary of Elan Corp (ELN).

The two businesses combined to form a new company called Alkermes plc, to be based in Dublin, Ireland, the current headquarters of Elan. The $1 billion merger was approved by Alkermes shareholders on Sept. 8.

Alkermes' current headquarters in Waltham, Mass., will be home to the newly formed companys research and development.

Through this transaction, we have strategically combined two highly innovative companies with proprietary technologies and important commercial products, creating a strong platform for accelerating future growth and increasing shareholder value, said Richard Pops, the chief executive of Alkermes Plc, in a statement.

As part of the agreement, Elan received $500 million in cash and 31.9 million shares, or a 25% stake, of Alkermes Plc. Shareholders of Alkermes Inc. will receive one share of the new company for each share currently owned.