[Viva] Fwd: CATIE News - Oral and topical PrEP not effective for women in VOICE study

Denise Becker dbecker106 at gmail.com
Thu Mar 21 10:18:54 PDT 2013 

---------- Forwarded message ----------
From: CATIE <mailer at newsletter.catie.ca>
Date: Thu, Mar 21, 2013 at 10:00 AM
Subject: CATIE News - Oral and topical PrEP not effective for women in
VOICE study
To: dbecker106 at gmail.com


**
    CATIE News - Bite-sized HIV/AIDS news bulletins
       CATIE News - Oral and topical PrEP not effective for women in VOICE
study

Pre-exposure prophylaxis, or PrEP, is a new tool that an HIV-negative
person may be able to use to reduce their risk of becoming infected with
HIV. It involves taking anti-HIV medications on a regular basis.

Recently, several types of PrEP have been investigated, including the daily
use of pills taken orally (oral PrEP) and the insertion of a gel into the
vagina either daily or before and after sex (topical PrEP). These types of
PrEP contain the antiretroviral drug tenofovir (called Viread when used in
pill form) or combinations of tenofovir and emtricitabine (sold as a
fixed-dose co-formulation pill called Truvada).

While some PrEP clinical trials have had promising results, others have not.
 Mixed results

Some research studies, such as
iPrEX<http://www.catie.ca/en/catienews/2010-11-25/truvada-hiv-prevention-some-good-news-caution-still-needed>,
PartnersPrEP<http://www.catie.ca/en/catienews/2011-08-03/prep-reduces-hiv-transmission-heterosexual-men-and-women>,
TDF2<http://www.catie.ca/en/catienews/2011-08-03/prep-reduces-hiv-transmission-heterosexual-men-and-women>and
CAPRISA
004<http://www.catie.ca/en/catienews/2010-09-24/prep-hope-and-excitement-greet-first-successful-microbicide>,
have shown that certain types of oral and topical PrEP are effective at
reducing the risk of HIV transmission in specific populations. The extent
to which PrEP reduced the overall risk of HIV transmission in these studies
has ranged widely, from 39% in CAPRISA 004 to 75% in PartnersPrEP, likely
due to varying levels of adherence among study participants.

In another study, known as
FEM-PrEP<http://www.catie.ca/en/catienews/2011-04-27/prep-study-closes-questions-remain-unanswered>,
oral Truvada did not appear to reduce the risk of HIV infection among
high-risk heterosexual women. This was surprising because daily Truvada was
found effective for women in the PartnersPrEP and TDF2 studies.

More recently, a study known as VOICE announced similar disappointing
results. A preliminary analysis of this study was presented at the
Conference on Retroviruses and Opportunistic Infections (CROI) in Atlanta,
Georgia, in March.
 The VOICE study

The VOICE (Vaginal and Oral Interventions to Control the Epidemic) study
was designed so that researchers could compare the effectiveness and safety
of different types of PrEP in preventing HIV infection in women.

More than 5,000 HIV-negative women from Eastern and Southern Africa were
enrolled in the study. The majority of these women were from South Africa
(81%), while a smaller proportion was from Uganda (6%) and Zimbabwe (13%).
Almost half of the participants were under 25 and most were not married
(79%).

Researchers randomly assigned the women to one of five study arms. Each arm
included approximately 1,000 women and they were asked to use or take one
of the following on a daily basis:

   - tenofovir vaginal gel
   - placebo vaginal gel
   - tenofovir (Viread) pill
   - Truvada pill
   - placebo pill

 All study participants were blinded, meaning they did not know which study
arm they were assigned to. They were also all provided with ongoing
adherence and risk-reduction counselling, testing and treatment for
sexually transmitted infections (STIs), and free condoms.
 Results

The study began enrolling participants in September 2009 and was scheduled
to end in August 2012. However, only the daily Truvada and placebo pill
arms continued until the expected end date of the study. The tenofovir
vaginal gel arm and the tenofovir pill arm were stopped
early<http://www.catie.ca/en/catienews/2011-12-01/confusion-over-contradictory-prep-results>because
interim data suggested they were not effective.

The results presented at CROI showed that the rates of HIV infection were
very similar in each of the five groups. Since there was no significant
difference in the rate of HIV infection between the PrEP and placebo
groups, the researchers concluded that none of the interventions were
effective at reducing the risk of HIV infection.

These results were surprising, as daily Viread and Truvada pills had
previously been found effective for women in the PartnersPrEP and TDF2
studies. Also, a tenofovir vaginal gel had been found effective in the
CAPRISA 004 study (when used before and after sex, not daily).
 Adherence

Similar to the FEM-PrEP study, poor adherence has been suggested as the
most likely explanation for the lack of PrEP effectiveness in the VOICE
study.

Although self-reported adherence was high among VOICE participants, blood
analysis of 773 participants assigned to daily PrEP showed that only 23% to
29% on average had detectable drug in their blood. This suggests that the
majority of study participants were not using or taking PrEP consistently.
Adherence was lower (and the rate of HIV infection higher) among young,
unmarried women compared to participants who were older and married.

Further analysis is being done to understand why adherence was low among
women in the VOICE study. These analyses are investigating individual and
community-based factors, such as attitudes and beliefs, which may have
influenced adherence.
 Conclusion

It is concerning that—within the context of controlled clinical trials—the
effectiveness of PrEP cannot be replicated and has ranged widely (from 0%
to 75%). As a result, it is unclear what impact PrEP may have on the HIV
epidemic outside of a clinical trial, particularly among populations that
may have trouble adhering to consistent PrEP use.

However, at the individual level, research shows that PrEP can be effective
at preventing HIV transmission when used consistently and when STIs are
managed through regular testing and treatment. Like all other HIV
prevention strategies, such as condoms and the effective use of treatment
by people living with HIV, this level of protection drops dramatically with
inconsistent and incorrect use.
 What’s next for oral PrEP?

In the United States, the Food and Drug Administration (FDA) has approved daily
Truvada for the prevention of HIV
infection<http://www.catie.ca/en/catienews/2012-07-17/truvada-approved-us-help-prevent-hiv-infection>and
the Centers for Disease Control and Prevention (CDC) has developed
interim guidelines for healthcare providers. Also, the World Health
Organization (WHO) has developed guidance on oral
PrEP<http://www.who.int/hiv/pub/guidance_prep/en/index.html>for use in
the context of demonstration projects.

Demonstration projects are currently underway in several parts of the U.S.
and will provide a better understanding of the effectiveness of PrEP and
adherence to daily pill-taking outside of a clinical trial. These projects
are also evaluating different strategies to improve adherence among PrEP
users.

Daily Truvada has not been approved for use as PrEP by Health Canada.
However, Truvada is available for the treatment of HIV and therefore some
doctors may be willing to prescribe it “off-label” for the prevention of
HIV infection.
 What’s next for topical PrEP

Vaginal gels for use as PrEP have not been approved by any regulatory
agencies and cannot be obtained “off-label” from healthcare providers.
There is currently an ongoing study, known as FACTS 001, that is
investigating the use of a tenofovir vaginal gel used before and after sex.
It is likely that results from this study will be needed before regulatory
approval can be considered. Smaller studies are also investigating the use
of gels in the rectum.

*—James Wilton*

*Resources*

VOICE Factsheet <http://www.mtnstopshiv.org/node/2003> – Microbicide Trials
Network

Pre-exposure prophylaxis—adherence is key and may explain disappointing
trial results<http://www.catie.ca/en/catienews/2012-03-15/pre-exposure-prophylaxis-adherence-key-and-may-explain-disappointing-trial-resu>–
*CATIE News*

Pre-exposure prophylaxis
(PrEP)<http://www.catie.ca/en/fact-sheets/prevention/pre-exposure-prophylaxis-prep>–
CATIE Fact Sheet

Is taking PrEP the right choice for
you?<http://www.projectinform.org/pdf/prep_msm.pdf>– Project Inform

*Reference:*

Marrazzo J, Ramjee G, Nair G et al. Pre-exposure Prophylaxis for HIV in
Women: Daily Oral Tenofovir, Oral Tenofovir/Emtricitabine, or Vaginal
Tenofovir Gel in the VOICE Study (MTN 003). *20th Conference on
Retroviruses and Opportunistic Infections, Atlanta, Paper#26LB,* *2012*.


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-- 
www.denise-becker.com
Queen's Gold Jubilee Medal
Queen's Diamond Jubilee Medal
cell: 250-870-1714
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