Aumentare o interrompere Haart nei soggetti con resistenze

Aumentare o interrompere per brevi periodi la Haart nei soggetti con multi resistenze non produce nessun effetto significativo.
E' quanto emerso da un nuovo studio americano.


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Treatment Intensification And Brief Treatment Interruptions Do Not Affect Treatment Outcomes In People With Multi-Drug Resistant HIV
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By Kieryn Graham and Courtney McQueen
Published: Apr 14, 2011 8:40 am

Results from a recent study indicate that, for people with multi-drug resistant HIV who need to change regimens, there are no significant advantages or disadvantages of antiretroviral treatment intensification or short treatment interruptions before restarting treatment when compared to standard treatment practices.

However, the results did suggest that treatment intensification may be more dangerous for patients with extremely low CD4 counts. The authors also noted that other studies have found that treatment interruptions lead to poorer prognoses and that current guidelines recommend against interrupting treatment.

Drug resistance is one of the main causes of antiretroviral drug failure. Individuals are considered resistant to an anti-HIV drug if their viral load (amount of HIV in the blood) does not remain low after treatment and/or testing confirms the presence of an HIV strain that is resistant to one or more classes of antiretroviral drugs.

Multi-drug resistant HIV, in which a person’s HIV is resistant to multiple classes of antiretrovirals, is associated with more limited treatment options, increased risk of AIDS-associated diseases, and death. Multi-drug resistance can arise from non-adherence to antiretroviral regimens, antiretroviral regimens that are only partially effective, or, for older HIV-positive adults, exposure to antiretrovirals sequentially rather than in combination prior to the advent of highly-active antiretroviral therapy.

Physicians primarily address drug resistance by changing a patient’s antiretroviral regimen to include anti-HIV drugs from different classes, particularly newer drug classes like integrase inhibitors. However, clinicians have also experimented with alternative strategies such as treatment intensification, in which a person is prescribed a regimen containing up to nine different antiretrovirals.

Alternative strategies may be particularly appropriate for people who cannot use newer antiretrovirals due to extensive drug resistance, treatment failure with newer drug classes, intolerable side effects, or limited access to newer, more expensive anti-HIV drugs. However, the safety and efficacy of these strategies have not been clearly established.

In this study, researchers compared the safety and efficacy of two different types of treatment interventions in people with multi-drug resistant HIV: switching to a “standard” antiretroviral regimen with up to four antiretrovirals versus switching to an intensified regimen with at least five anti-HIV drugs; and starting the new regimen right away versus interrupting treatment for 12 weeks before starting retreatment.

The study included 368 HIV-positive adults, 98 percent of whom were men. All study participants had CD4 (white blood cell) counts of 300 cells per microliter of blood or less and had either experienced treatment failure with two different antiretroviral regimens or had shown resistance to at least three classes of antiretrovirals (nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, and protease inhibitors).

Participants were randomly assigned to either a new standard regimen or a new intensified regimen. Additionally, half were selected to start treatment immediately, while the other half waited 12 weeks to begin treatment.

The researchers monitored CD4 counts, viral loads (amount of virus in the blood), and the time to the first AIDS-related illness or death for each participant. Participants were followed for a median of four years.

Results showed that after 24 weeks, there were no significant differences in CD4 counts or viral loads between the groups. Over the course of the study period, CD4 counts increased by an average of about 100 cells per microliter and average viral loads decreased to around 1 percent of their original values for participants in all treatment groups.

Results also showed that 35 percent of participants died during the study period. The researchers determined that 52 percent of the deaths were HIV-related, 2 percent were due to antiretroviral medications, and the rest were either non-HIV-related or of undetermined causes.

In addition, 27 percent of participants experienced an AIDS-related illness during the study period, the most common of which were esophageal thrush (a yeast infection in the esophagus) and pneumonia.

There were no significant differences in time to death or AIDS-defining illness among the treatment groups. There was also no significant difference in the number or type of AIDS-defining illnesses between treatment groups.

However, for participants with baseline CD4 counts lower than 36 cells per microliter, more deaths occurred with intensification of treatment compared with standard treatment (71 percent versus 49 percent).

For more information, please see the study in PLoS One.
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