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Lopinavir/ritonavir monotherapy in clinical practice

Purpose of the study

To assess the usefulness of monotherapy with lopinavir/ritonavir (LPV/r) as an option for antiretroviral treatment in clinical practice.


Seventy-seven subjects (56 men, median age 44.5 years) with HIV-1 RNA <50 copies/mL for at least 6 months, were switched to LPV/r as single antiretroviral agent. Reason for changes were simplification strategy (36.4%) or toxicity (63.6%) either mitochondrial toxicity (55.8%) or other (7.8%). Treatment with LPV/r was maintained for at least 3 months.

Summary of results

The average time from HIV-1 diagnosis to starting HAART was 54 months. Patients had received a median of 7 antiretroviral drugs (range 3-14). The previous antiretroviral regimen included LPV/r in 55 (71.4%) patients. After a mean (±SD) follow-up of 25 (±16) months (median 22 months), viral load remained undetectable in 68 patients (90.7%) (9 of them after reintroduction of triple therapy for reasons other than virological failure), and virological failure was detected in 9 (11.7%), due to poor adherence in 7 (77.8%). The median time of undetectable viral load prior to initiating LPV/r monotherapy was 36 months. The mean CD4+ T cell count at the time of beginning LPV/r was 518.9 cells/mm3 (range 33−1433) and the end of follow-up 634.5 cells/mm3 (range 99−1547), with an increase of 115.6 cells/mm3. In 8 patients, 13 blips were detected (viral loads > 50 copies/mL and < 500 copies/mL), which did not warrant a change in therapy. Differences between patients with and without virological failure during LPV/r monotherapy included: older age at HIV-1 diagnosis (40.2 vs 30.7 years, P < 0.049), time of undetectable viral load prior to starting monotherapy (29 vs 45 months, P = 0.05), and CDC category C (77.8% vs 42.6%, P = 0.074). On the other hand, there were no significant differences according to sex, risk group, previous failure to PIs( 9 patients), nadir CD4+ T cell count, or reasons to change to monotherapy. In the Cox regression analysis, age was independently associated with virological failure.


LPV/r monotherapy has been an effective alternative in clinical practice either as a simplification strategy or in patients in which toxicity reduces the selection of antiretroviral drugs. Poor adherence and greater age were related to a higher rate of therapeutic failure.

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This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Caso, A., Valencia, E., Moreno, V. et al. Lopinavir/ritonavir monotherapy in clinical practice. JIAS 13 (Suppl 4), P50 (2010).

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