According to a recently released study in the Clinical Infectious Diseases Journal, once-daily administration of antiretroviral treatment is just as effective as twice-daily administration.

Researchers compared the efficacy of both types of treatment regimens by studying HIV positive patients who had not undergone previous drug therapy.

Patients were randomly separated into two groups; both received Kaletra (lopinavir/ritonavir). The first group received 400 mg of lopinavir and 100 mg of ritonavir twice a day, while the second group received 800 mg of lopinavir and 200 mg of ritonavir once a day.  All patients were also required to take daily doses of 200 mg of Emtriva (emtricitabine) and 100 mg of stavudine (Zerit) or a daily dose of 300 mg of Viread (tenofovir).

During the 48-week study, the researchers monitored each patient’s sustained virologic response, which was defined as being able to maintain an HIV RNA level of fewer than 200 copies per milliliter of blood plasma.

At the end of the 48-week study, researchers found that adherence to the Kaletra treatments were better in the once-daily group than in the twice-daily group.

Currently, among antiretroviral therapy users, the rate of adherence is approximately 70 percent.

This is important because adherence to a medication, or the ability of a patient to take a medication in the manner intended by the prescribing physician, can greatly influence the effectiveness of antiretroviral therapy. Non-adherence has been known to cause HIV to become resistant to certain medications and can lead to increased HIV-related mortality and morbidity.

However, individuals who began the study with plasma HIV RNA levels greater than 100,000 copies per milliliter experienced an better sustained virologic response in the twice-daily regimen than in the once-daily regimen. This suggests that a twice-daily treatment regimen may be more advantageous for those who have higher plasma HIV RNA levels prior to drug therapy.

Despite this finding, researchers observed that, overall, patients in the once-daily group and the twice-daily group had similar sustained virologic responses.

For more information, please see the Chicago Journals Web site.