Currently 35million persons are living with HIV-1 infection
and about half of them are women. The majority of these live in sub Saharan
Africa, which has the highest incidence of HIV infection in any given
population.
Using antiretroviral (tenofovir ) as pre exposure
prophylaxis ( PrEP) in the form of pills
and vaginal gel is assuring approach against fight against HIV, but patient compliance is very poor and
protection was not shown.
Vaginal rings containing exogenous hormones for
contraception (Nuvaring ) and HRT are licensed and in use since long and
provide a sustained and control release of medication.
The results of two studies were presented at Conference on
Retroviruses and Opportunistic Infections (CROI) from February 22 to February 25, 2016, in Boston,
Massachusetts.
One of the study (ASPIRE study) was published today in New England Journal of Medicine and the result of other study( Ring study) was
presented as an abstract in the conference.
The trials evaluated the safety and efficacy of a monthly vaginal
ring (Ring-004), containing 25 mg of Antiretroviral (ARV) dapivirine, which
women placed themselves and replaced each month.
Both the dapivirine and placebo rings were manufactured by
QPharma under contract with the International Partnership for Microbicides.
Both studies were double blind randomized placebo controlled
trials. The ASPIRE study enrolled 2629 healthy, sexually active, nonpregnant,
HIV-1–seronegative women between the ages of 18 and 45 years at 15 research
sites in Malawi, South Africa, Uganda, and Zimbabwe women: 1313 in the
dapivirine group and 1316 in the placebo group.
In the ring study 1959 women (1762 in South Africa and 197 in Uganda) were randomized in a 2:1
ratio to receive either a dapivirine ring or a placebo ring.
In both studies,the primary efficacy end point was HIV-1
infection, identified with the use of a standard seroconversion algorithm and the primary safety endpoint was incidence of adverse events
(AEs).
In both trials the ring was found
to be effective in reducing the incidence of HIV-1 infection by 27% (ASPIRE
study) and 31% ((Ring study). Both study found that in women less than 21 years
of age, the risk of acquiring the infection was not much decreased; probably
the women were not compliant enough.
Compliance is also a big issue with the Truvada (Tenofovir
disoproxil/emtricitabine), the once a day oral PrEP. Studies have found
it to be effective in preventing infection in 92% of cases, but adherence to
daily regimen is a problem.
The ring adds a new tool in HIV prevention armament, which
could be used discreetly by women, without asking her male partner to use
protection. It is especially useful in African countries were women are at
highest risk. In the study about 1 in 3 infection were prevented.
The ring is also cost effective, costing only $5 as compared
to other PrEP which costs thousands of dollars. Although it is not in the market
yet, it gives a lot of hope and optimism for HIV prophylaxis.
Reference:
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