 STUDY PROCEDURES: A baseline HIV-RNA, CD4 and routine labs will be collected if the most recent results are not collected within the 4 weeks prior entering the study. Patients will be followed for HIV-RNA and CD4 at w1, w4, w8, w16, w24, w 36 and w48. After w48, durability of response to lopinavirr single-drug therapy will be studied long-term up to w96. Routine hematology and clinical chemistry including fasting triglycerides and cholesterol, total and HDLLDL ratio will be measured at w4, w16, w24, w 36 and w48. A central laboratory will be used for HIV-RNA determinations and to archive plasmacell samples for further genotype test in case of rebound. 