Pharmaceutical Japanese drug major Astellas Pharma (TSE: 4503) says that it has engaged Citigroup Global Markets to conduct, in conjunction with executive management, a review of the company's strategic alternatives with regard to its Prosidion subsidiary, which was acquired as part of Astellas' $4 billion purchase of USA-based OSI Pharmaceuticals last year (The Pharma Letter May 4, 2010). 11 January 2011