Three-drug regimen most effective in HIV
A specific combination of three anti-HIV drugs appears to be a more effective initial regimen than other drug combinations tested in a large international study.
Two reports published in The New England Journal of Medicine last week
show that while all of the regimens tested were effective, patients who
started therapy with a combination of zidovudine, lamivudine and efavirenz
were successfully treated for longer.
The first part of the trial compared several triple therapy regimens
to determine their optimal sequencing in 620 patients who had not previously
been treated. They received either zidovudine and lamivudine or stavudine
and didanosine. The third drug in the triple therapy regimens was either
efavirenz or nelfinavir. After treatment failure, patients in each of
the four groups were switched to a second three-drug regimen.
The researchers found that failure of subsequent regimens was delayed
for longest in the patients who started treatment with a combination
of zidovudine, lamivudine and efavirenz. “Even among the subjects
who had high viral loads at screening the combination of zidovudine,
lamivudine and efavirenz was more effective than the other regimens,” they
comment (2003;349:2293).
The second part of the trial compared the use of four-drug regimens with
the use of two consecutive three-drug regimens in 980 patients (ibid,
p2304).
After an average of 2.3 years, the four-drug regimens were no more effective
than any of the sequential three-drug regimens. The researchers point
out that there were relatively few first regimen failures among patients
who began therapy with zidovudine, lamivudine and efavirenz. This regimen
also led to faster viral load suppression than the four-drug regimens.
Another important finding that emerged from the two studies was that
the combination of stavudine and didanosine should not be used for the
initial treatment of HIV infection because of unacceptably high rates
of adverse effects. |
