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PI Monotherapy for HIV — An Idea Whose Time Has Passed?

Patients who switched from suppressive triple-drug therapy to boosted protease-inhibitor monotherapy had unreasonably high rates of treatment failure.

Before single-tablet antiretroviral regimens became widely available, one suggested strategy for treatment simplification was the use of ritonavir-boosted protease inhibitor (PI) monotherapy. Although this approach required that patients take multiple pills each day, it was intended to reduce costs, diminish drug-related adverse events, and limit the resistance consequences of virologic failure. In randomized clinical trials, switching to PI monotherapy was reasonably efficacious compared with continuing triple-drug therapy, but low-viremia treatment failure was distressingly common.

In the present report, investigators describe a cohort of 529 virologically suppressed patients in France who switched to boosted PI monotherapy between 2006 and 2010. Twelve months after the switch, the probability of virologic failure was 21%, and the probability of treatment failure (defined as virologic failure, reintroduction of other antiretrovirals, or death) was 38%. At 24 months, these probabilities rose to 31% and 52%, respectively. Risk factors for both types of failure included a history of AIDS, previous virologic failure with a PI, a shorter duration of virologic suppression before the switch, and use of atazanavir (vs. lopinavir or darunavir) for monotherapy.

Comment: Switching patients from suppressive triple-drug therapy to ritonavir-boosted PI monotherapy may have seemed like a reasonable option at one time, but not anymore. Studies have consistently shown that these switches increase the risk for low-level viremia, and the single-tablet regimens now offer a more convenient and effective way of simplifying treatment. Although it might be possible to identify patients for whom a switch is likely to be successful (e.g., those with high baseline CD4-cell counts, long durations of virologic suppression, and no AIDS-defining conditions or previous treatment failure), the only advantage to doing so appears to be cost. There seems to be no need to conduct additional trials or advocate for this approach as a preferred option.

— Charles B. Hicks, MD

Published in Journal Watch HIV/AIDS Clinical Care December 3, 2012

Citation(s):

Guiguet M et al. Boosted protease inhibitor monotherapy as a maintenance strategy: An observational study. AIDS 2012 Nov 28; 26:2345.

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Review and add to remarks on this article

• The end of PI monotherapy
  Rob Camp, 14 Dec 2012 2:15 PM EST
  Specialty: Infectious Disease
  Rather than throwing the baby out with the bathwater, maybe we could consider "those with high baseline CD4-cell counts, long... [more]

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