Eisai is acquiring the US firm AkaRx in a deal which will give the Japanese drugmaker access to a mid-stage thrombocytopaenia drug.

The Tokyo-based group is taking up the option to buy AkaRx that it obtained when it acquired MGI Pharma in January 2008 for $3.9 billion. It is now paying out $255 million for the New Jersey-based firm, thus bagging the rights to AKR-501, which is in Phase II for idiopathic thrombocytopaenic purpura and thrombocytopaenia associated with liver diseases. Eisai also said it will explore the drug’s potential as a treatment for cancer chemotherapy-induced thrombocytopenia.

As a result of the acquisition, however, Eisai has cut its profit forecasts by 36%. It now expects net profits of 40.30 billion yen (about $450 million) for the year to March 31, 2010., down from 63.00 billion yen. The company’s sales forecast is unchanged at 820 billion yen.