• Once-a-day therapy for HIV infection (TuPpB1167)
  Authored by F. Maggiolo, M. Migliorino, S. Caprioli, R. Maserati, L. Rizzi, M. Rizzi, F. Suter

• Nevirapine (NVP) shown to be equally effective at both high and low viral loads (Poster Presentation TuPpB1168)
  Authored by F. Raffi, V. Reliquet

• An open randomized study comparing d4T + ddI and nevirapine (Qd) vs. d4T and nevirapine (Bid) in antiretroviral-naive chronic HIV-1-infected patients in very early stages: Spanish scan study. Final results (Poster Presentation TuPpA1156)
  Authored by G. Felipe, K. Hernando, S. Maria Antonia, A. Julio, A. Miquel, R. Joan, D. David, S. Ferran, G.-S. José Luis, F. Elena, C. Anna, G. Teresa, P. Tomas, M. José M., G. José M.

Once-a-day therapy for HIV infection (TuPpB1167)

Another exploration for defining a combination that can be taken just once a day was shown here. This study took advantage of the availability of two medications that have already been shown to be successful and are approved by the U.S. Federal Drug Administration (FDA) to be taken just once a day: efavirenz (Sustiva) and ddI (Videx). Here the researchers added a third medication, 3TC (Epivir), which is usually taken twice a day, and did a study where it was used just once a day, taking both tablets at the same time. They enrolled 70 people, all of whom took this as their first antiviral combination. The average initial viral load was just over 100,000 -- a cut-off that has been shown in several studies to be important, as those with a viral load over this level have been less successful on a number of combinations. Their results show that about 70% overall achieved a viral load below 50 copies after one year -- but only three patients had viral rebound at the end of a year. Most of the reasons for a lack of success at one year was due to side effects and early drop-outs from the study. There was no difference in the success rate on this combination for those whose baseline viral load was either above or below 100,000 copies, consistent with all other studies of efavirenz and two nucleosides.

This study provides some additional options for those attempting to define a very simple combination. While 3TC is only approved for use as a twice-a-day medication, much research is going on to determine if it can be successful when taken just once a day. While more work will be needed to be sure that 3TC is equally successful when taken once a day, this study does provide some information that suggests this might some day be the standard way to use 3TC.

Nevirapine (NVP) shown to be equally effective at both high and low viral loads (TuPpB1168) and
An open randomized study comparing d4T + ddI and nevirapine (Qd) vs. d4T and nevirapine (Bid) in antiretroviral-naive chronic HIV-1-infected patients in very early stages: Spanish scan study. Final results (TuPpA1156)

With the increased use of non-nucleosides in combinations over the past few years, there has been a lot of research exploring the success rates of nevirapine (Viramune). Mainly, there are two concerns with the use of nevirapine:

• It was approved for use as a twice-a-day pill, as compared to efavirenz (Sustiva), which is taken just once a day.

• While efavirenz has shown success in those with any viral load, this was less clearly seen from studies using nevirapine.

Here two groups of researchers looked at answering these two questions about the use of nevirapine.

In 1156, the authors report the results of a one-year study which used d4T, ddI, and either the standard 200mg twice-a-day nevirapine, or 400mg once a day. This study was done in patients just starting their first combination, and they focused this study for patients whose baseline CD4 count was over 500. At one year there was no difference in the success of nevirapine in the two different arms of this study. In both arms about 70% of the patients had a viral load below 200 copies, and similar CD4 count increases were noted.

In 1157, the authors explored five nevirapine studies, and focused on the success rate for people whose baseline viral loads were high, either over 50,000 or over 100,000 copies (5 log). Using the most stringent analysis, where missing data is called a failure, there was no difference in the rate of getting a viral load below 50 copies in the low vs. high viral load groups. Looking at just patients who were still on treatment, there was also a similar success rate regardless of initial viral loads. The authors conclude that there is no apparent difference in the success rates of combinations which use two nucleoside RT inhibitors plus nevirapine at higher viral loads. These results are based on an analysis of over 400 patients overall.

Where does this leave us in understanding the use of nevirapine? All the studies done so far have shown no difference when nevirapine has been given either once or twice a day. As a result, while confirmation studies are underway, the use of nevirapine in either schedule has been common, and the choice is left up to the patient to decide which is more convenient. Whether nevirapine is shown to be as successful as efavirenz at all viral loads is one outcome of a randomized comparison trial currently underway, and in time we will have even more data to guide us about this important aspect of the use of this medication.