Trial of antiretroviral for HIV prevention on hold

Khabir Ahmad

The Lancet. Volume 4, Number 10 01 October 2004

The Cambodian government has opposed plans by an international team of
researchers to assess the role of an oral antiretroviral drug,
tenofovir, in HIV prevention among HIV-uninfected sex workers in
Cambodia because of concerns over possible harm.

On August 13, researchers from the University of California San
Francisco (UCSF; USA), the University of New South Wales (UNSW;
Australia), and the Cambodian National Center for HIV, AIDS,
Dermatology, and STDs (NCHADS) halted preparations for the
double-blind, placebo-controlled trial after "a verbal directive" from
the Cambodian Prime Minister, Hun Sen, that the trial violated human
rights.

The trial is on hold, pending further communication from Sen's
government, according to the US National Institute of Allergy and
Infectious Diseases (NIAID), which is funding the study. "It is
ultimately the decision of the Cambodian team members and their
government whether or not the trial goes forward and we will respect
their decision", Mary Fanning of NIAID told TLID.

960 HIV-uninfected female sex workers in Cambodia's capital, Phnom
Penh, were to receive either 300mg of tenofovir or placebo daily for 1
year. But they have declined to participate in the study unless they
are given medical insurance for 30–40 years for any tenofovir-related
adverse events. "Who will treat us if we develop side effects of this
drug after 1 year?", asks Keo Tha whose sex workers' rights group,
Women Network for Unity, has led the campaign against the trial. NIAID
disagrees, arguing that it did not anticipate "long-term negative
reactions to the drug". The controversy has delayed the trial by
several months.

Tenofovir disoproxil fumarate, manufactured by Gilead Sciences under
the brand name Viread, has been used to treat individuals already
infected with HIV. But its safety and effectiveness among
HIV-uninfected people is unclear. NIAID maintains that "safety trials
of tenofovir have been conducted in small numbers of people who are
not infected with HIV. These trials have found no safety concerns to
date".

The trial protocol has already been approved by the National Ethics
Committee for Health Research in Cambodia, and committees for research
on human beings at UCSF and UNSW. However, leading ethicist Arthur
Caplan (University of Pennsylvania, PA, USA) believes that the
controversy over placebo-controlled trials among vulnerable
populations such as prostitutes shows the need for an international
consensus on research ethics, study design, and oversight. "Those
sponsoring these studies need to attend more closely and more
seriously to the difficult ethical issues they raise", Caplan concluded.

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