Diffuse large B cell lymphoma (DLBCL) is the most common non-Hodgkin's lymphoma, accounting for between 30% and 50% of the patients. Although it is considered a curable disease, still at least 40 % of the patients will fail first line chemotherapy. The International Prognostic Index (IPI) score and the age adjusted IPI (aIPI) has been used since they were published to identify patients with different outcome.

There is not standard therapy for young patients with DLBCL and unfavourable IPI score. The survival of these patients remains poor, with EFS around 40%.

The combination of RCHOP with new drugs is an attractive approach to treat these patients.

The goal is to evaluate the proportion of patients with Event-Free Survival (EFS) after 2 years, with a diagnosis of DLBCL with an aIPI > 1 or an aIPI =1 with increased levels of beta-2-microglobulin (above the Upper Limits of Normal.)

Diffuse large B cell lymphoma (DLBCL) is the most common non-Hodgkin's lymphoma, accounting for between 30% and 50% of the patients. Although it is considered a curable disease, still at least 40 % of the patients will fail first line chemotherapy. The International Prognostic Index (IPI) score and the age adjusted IPI (aIPI) has been used since they were published to identify patients with different outcome.

CHOP chemotherapy administered every 21 days has been for years the standard therapy for advanced DLBCL achieving a long term overall survival (OS) of about 40%. Many studies show that the addition of the monoclonal antibody Rituximab improves the patients survival achieving higher rates of event-free survival in elderly patients with both,favourable and unfavourable IPI score. R-CHOP also improved survival in young patients with favourable IPI score.

There is not standard therapy for young patients with DLBCL and unfavourable IPI score. The survival of these patients remains poor, with EFS around 40%.

The combination of RCHOP with new drugs is an attractive approach to treat these patients.

The investigators propose a phase II randomized clinical trial for young patients with unfavourable IPI score DLBCL using 6 cycles of the combination of subcutaneous Bortezomib with R-CAP (RCHOP without vincristine, to avoid neuropathy) comparing with the standard immunochemotherapy regimen R- CHOP every 21 days.

The goal is to evaluate the proportion of patients with Event-Free Survival (EFS) after 2 years, with a diagnosis of DLBCL with aIPI > 1 or aIPI =1 with increased levels of beta-2-microglobulin (above the Upper Limits of Normal).

Inclusion Criteria:

• Patients diagnosed with primary diffuse DLBCL who have never received treatment for this condition.
• Age between 18 and 70 years.
• Age-adjusted IPI (aIPI) higher than 1, or equal 1 with high levels of beta-2-microglobulin (above UNL)
• Cluster of Differentiation 20 (CD20) positive b lymphocytes.
• Eastern Cooperative Oncology Group (ECOG) 0-3.
• More than 12 weeks of life expectancy.
• Signed Informed Consent.
• Nor pregnant women nor breast-feeding women without heterosexual activity during the entire study. Women with heterosexual activity only if they are willing to use two methods of contraceptive. The two contraceptive methods can be, two barrier method or a barrier method combinated with an hormonal contraceptive method to prevent pregnancy, used during the entire study and until 3 months after the study completion.

Exclusion Criteria:

• Pregnant women or in breast-feeding period, or adults in childbearing period not using an effective contraception method.
• Patients with Central Nervous System (CNS) lymphoma.
• Severely impaired renal function (creatinine> 2.5 UNL) or hepatic function impairment (bilirubin or Alanine Amino Transaminase (ALT) / Aspartate Aminotransferase (AST) > 3 UNL), unless it is suspected to be due to the disease.
• Human immunodeficiency virus (HIV) positive patients
• Patient previously treated for the DLBCL
• Positive determination of chronic hepatitis B (defined as positive serology for HBsAg). It will be allowed to enroll patients with hidden or previous hepatitis B (defined as positive antibodies against the core of the hepatitis B virus [HBcAb] and HBsAg negative) if undetectable Hepatitis B Virus (HBV) DNA.
• Positive results for hepatitis C (antibody serology for hepatitis C virus ((HCV)). Patients with HCV positive may only participate if the Polymerase Chain Reaction (PCR) result is negative for HCV RNA.
• History of cardiovascular disease with ventricular ejection fraction < 50%.
• Patients with severe psychiatric conditions that may interfere with their ability to understand the study (including alcoholism or drug addiction).
• Patients with known hypersensitivity to murine proteins or any other components of the study drugs.
• Transformed follicular lymphoma.
• History of other neoplastic malignancy with < 5 year of complete response (except for Squamous Cell Carcinoma of the Skin or cervical Carcinoma in situ).
• Presence of uncontrolled conditions: cardiac, respiratory, neurologic, metabolic etc., not related to lymphoma.
• Uncontrolled hypertension (diastolic blood pressure over 110 mmHg).