Japanese pharmaceutical company Daiichi Sankyo Co. said Wednesday it will buy a controlling stake in India's largest drug maker Ranbaxy Laboratories Ltd. in a tender offer worth as much as $4.6 billion.

The agreement allows Tokyo-based Daiichi Sankyo to buy at least 50.1 percent of the Indian generic drug maker's voting rights in the tender offer through March 2009, the Japanese company said in a statement.

Sankyo said Ranbaxy will become the Japanese company's subsidiary when the deal is completed. Ranbaxy Chief Executive and Managing Director Malvinder Mohan Singh will remain his current post.

Separately, the two companies said in a joint statement that the deal would benefit them with sustainable growth, an expanded global reach, strong growth potential and cost competitiveness.

The proposed transaction "provides the opportunity to complement our strong presence in innovation with a new, strong presence in the fast growing business of non-proprietary pharmaceuticals," said Daiichi Sankyo President and Chief Executive Takashi Shoda in a statement.

Singh said Ranbaxy's association with Daiichi Sankyo "puts us on a new and much stronger platform to harness our capabilities in drug development, manufacturing and global reach."