Assessment of Efficacy and Safety of Front-line Fludarabine, Cyclophoshamide and Ofatumumab Chemoimmunotherapy in Young Patients With Chronic Lymphocytic Leukemia.

Given that: * rituximab, fludarabine and cyclophosphamide (FCR) front-line treatment was associated with a high OR rate, superior PFS and OS as compared to fludarabine and cyclophosphamide regimen; * a direct relationship between the dose of rituximab and the response rate has been reported; * ofatumumab, as single agent, proved activity in CLL patients with refractory disease; * ofatumumab, fludarabine and cylophosphamide (O-FC) front-line treatment has been associated with a high complete response (CR) rate; * the expected grade 3-4 granulocytopenia could led to reduce the dose intensity of study drugs (FC) and increase the infection rate; a schedule combining FC with an increased dose of ofatumumab associated to primary phrophylaxis of granulocytopenia could be associated with an improvement in the CR rate. The purpose of this study is to determine whether we could improve the CR rate of the golden standard treatment for fit patients with CLL , the FCR regimen, with a chemoimmunotherapy including FC combined with an increased dose of the monoclonal antibody ofatumumab, given every other week (FCO2) associated with a primary prophylaxis of granulocytopenia.