Roche says that it is looking to increase its holding in Japanese partner Chugai Pharmaceutical Co to 59.9% from its current stake of 50.1%.

The Swiss firm is to offer Chugai shareholders 1,730 yen (around $16.66) per share, which represents an 11.7% premium over the closing price of the stock on May 21. Roche noted that the transaction is based on the group's right to increase its stake to 59.9% at any time after the fifth anniversary of the strategic alliance which was set up in October 2002.

Roche’s chairman Franz Humer said that the firm is increasing its stake “because we believe in both the long-term potential of the Japanese market and in the strategic importance of this successful partnership”. He added that since the pact started, “our relationship has intensified in all areas to the benefit of both companies.”

Chugai has been responsible in Japan for the launch of Avastin (bevacizumab) for colorectal cancer, Copegus (ribarivin) in combination with Pegasys (peginterferon alfa-2a) for hepatitis C and the lung cancer drug Tarceva (erlotnib). It has also been involved in “significant line extensions” for Xeloda (capecitabine; adjuvant colon cancer) and Herceptin (trastuzumab; adjuvant breast cancer).

Actemra (tocilizumab), filed for rheumatoid arthritis in the USA and Europe in November 2007, is the first Chugai medicine that Roche is developing worldwide commercialization, while R7201 (or CSG452), one of three early-stage compounds that the Basel-based group licensed from Chugai in 2007, has started Phase I trials for type 2 diabetes.