Salix first approached Santarus about merger in 2010

Salix Pharmaceuticals first expressed interest in acquiring specialty drug company Santarus in June 2010, but Santarus officials found the initial offer inadequate, according to a new regulatory filing.

Raleigh-based Salix announced plans to acquire Santarus for $2.6 billion last month. Salix is paying $32 a share for the San Diego-based company.

According to the regulator filing, in a written letter to Santarus CEO Gerald Proehl in June 2010, Salix CEO Carolyn Logan expressed interest in acquiring the company for between $4.50 and $5 per share in cash.

Although Santarus officials turned down the offer, they retained Stifel, Nicolaus & Co. in February 2012 to explore possible mergers.

Talks about a possible merger with Salix didn’t resume again until June of this year, when Salix executives contacted Proehl again. A month later Salix made a written letter of interest to acquire Santarus for between $28 and $30 a share.

Logan later made a revised offer of $32 a share, or 36 percent above where the company’s share price closed the day prior to the deal being announced.

Santarus’ board of directors solicited offers from 15 other possible buyers, according to the regulatory filing. None submitted an offer for the company, including one that signed a confidentiality agreement.

Salix and Santarus expect their deal to close in the first quarter of next year.

Salix sells drugs to treat gastrointestinal ailments, an area that Santarus also focuses on. Combining the two businesses will give Salix a portfolio of 22 drugs with annual revenue of nearly $1.35 billion.

Salix shares closed Tuesday at $84.81, down 49 cents. The stock is up 16 percent since the Santarus deal was announced.