Flurry of trials published as AIDS conference opens
A large array of trials on HIV therapy were published this week, coinciding with the 15th international conference
on AIDS held in Bangkok, Thailand.
The theme of the conference was “Access for all”, echoing
the World Health Organisation’s continuing calls for more action
on HIV and AIDS in the developing world. Several studies presented at
the congress, were simultaneously published in medical journals.
An international group based in the Americas and Europe compared the
efficacy and safety of two nucleoside reverse transcriptase inhibitors,
emtricitabine and stavudine. The 60-week trial involved 571 antiretroviral-naive
HIV-1 patients with viral loads >=5,000 copies per ml. Patients were
randomised to receive either emtricitabine or stavudine with open label
didanosine and efavirenz.
At week 24, patients in the emtricitabine group had a higher probability
of persistent virological response <=50 copies/ml than with efavirenz
(85 per cent versus 76 per cent). At the end of the trial, when emtricitabine
had been offered on an open-label basis, the probability of this response
was 76 per cent versus 54 per cent. Stavudine patients had a 15 per cent
risk of adverse reaction compared with 7 per cent of those on emtricitabine
(JAMA 2004;292:180–90).
A three-year trial of tenofovir disoproxil fumarate (DF) versus stavudine,
given with lamivudine and efavirenz, reports equal efficacy between the
two. The study involved 602 antiretroviral-naive patients with HIV RNA
levels >5,000 copies/ml. By week 48, 80 per cent of tenofovir DF and
84 per cent of stavudine patients had reached an RNA level of <400copies/ml.
At week 144, the figures were 71 per cent and 64 per cent, respectively.
Equivalence was demonstrated with viral loads of < 50 copies/ml at
week 48 through to week 144. However, the authors say that tenofovir
DF appeared to be associated with better lipid profiles and less lipodystrophy
than stavudine (ibid 2004;292:191–201).
A US trial addressing potential problems with lipodystrophy hints that
growth hormone releasing hormone (GH-RH) may help. The US trial looked
at 31 HIV-infected men with lipodystrophy, assigned either GH-RH or placebo
subcutaneously for 12 weeks. The authors say that the agent was well
tolerated and effectively increased levels of insulin-like growth factor
(reflecting changes in GH levels). Total and regional body composition
improved with GH-RH (ibid 2004;292:210–218).
Three studies published this week look at HIV treatment in perinatal
disease. A study in Thai women found that a single dose of nevirapine
at the beginning of labour, combined with a short course of zidovudine,
dramatically reduced the chance of passing HIV from mother to child.
Transmission rates were reduced to below 2 per cent — similar to
those found with three drug regimens used in developed countries. However,
a second study showed that after giving birth, some women harboured nevirapine-resistant
strains of virus and had reduced efficacy of subsequent triple therapy
which included nevirapine. In Africa, researchers found nevirapine effective
in
reducing perinatal HIV transmission, but a combination with zidovudine
did not improve outcome further (JAMA 2004;292:202-9).
In a futher study of 167 treatment-naive patient on saquinavir combined
with two nucleoside reverse transcriptase inhibitors, 96 per cent achieved
HIV RNA levels of <400 copies/ml and 91 per cent achieved <50 copies/ml
after 24 weeks. This marks the best responses yet seen. |
The
Pharmaceutical Journal
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