Mapping Pathways is a multi-national project to develop and nurture a research-driven, community-led global understanding of the emerging evidence base around the adoption of antiretroviral-based prevention strategies to end the HIV/AIDS epidemic. The evidence base is more than results from clinical trials - it must include stakeholder and community perspectives as well.

Showing posts with label efficacy. Show all posts
Showing posts with label efficacy. Show all posts

05 June 2012

Hoover Institution: Reshaping Global Health, Time for a Structural and Philosophical Shift

via Hoover Institution Stanford University, by Mark Dybul, Peter Piot, and Julio Frenk

Excerpt:

However, the focus on specific diseases has imposed and exposed fault lines in delivering services in places where many suffer from multiple health issues at the same time or at varying points in their lives. Although studies have shown that hiv interventions have reduced overall mortality and that malaria and immunization programs have reduced childhood mortality in the near term, it seems highly likely that more lives will be durably saved if a person afflicted by different health problems has access to services for all of them. Although there are limited supportive data, we believe it is likely that an integrated approach focused on the health of a person and community is more cost-effective than a silo approach focused on a specific disease or health threat. Yet, existing global health institutions were designed for specific diseases and have not effectively shifted to embrace a broader vision. It is time for a Bretton Woods-style agreement to guide a new international health strategy and rationalize its structure.

Read the rest.


[Content that is linked from other sources is for informational purposes and should not construe a Mapping Pathways position. Please look for us on Facebook here www.facebook.com/MappingPathways and you can follow us on Twitter @mappingpathways as well.]

14 February 2012

In Conversation with Nomita Chandhiok: Exploring the ‘tool box’ of HIV prevention strategies

Original content from the Mapping Pathways blog team


“If a woman, for whatever reason, is unable to negotiate the use of a condom during sex, at least she can have something else to protect herself with  something that can help put her in control.”

Doctor Nomita Chandhiok is one smart lady. A gynaecologist by training, she is a scientist and researcher in the Division of Reproductive Health at the Indian Council of Medical Research (ICMR), the premiere research body of the government of India. Her job is to identify issues related to women’s health, sexual reproductive health, women’s infection, and HIV prevention that are relevant to India, and then conduct and coordinate studies that push forward research on these issues.

“HIV is a high priority for the Council,” says Dr. Chandhiok. “ARVs as prevention have really evolved.” She explains that all HIV prevention and treatment policies fall under the Indian government’s NACO programme. “As part of this programme, we would promote HIV prevention strategies such as PrEP or microbicides. Our focus so far has been on promoting condom use and safe sex practices, but now there could possibly be these new tools as well.”

Creating the toolbox
In particular, the ICMR is currently running a number of pre-clinical trials for product development and screening for microbicides. The organisation recently finished a Phase 1 trial that looked at an indigenously produced microbicide called Basant (the product is curcumin/turmeric based). The product was tested on 30 women and was found to be safe, says Dr. Chandhiok. Further studies would explore the post-coital efficacy of Basant and its male tolerability in 30-40 men. A study is also ongoing to identify and prepare six sites in the country for phase III microbicide trials. Dr. Chandhiok explains that these sites are located in three high-prevalence Indian states – Maharashtra, Andhra Pradesh, and Karnataka. The ICMR is seeking to determine the HIV incidence and prevalence rate amongst 9000 commercial sex workers in six districts in these areas. “Once we know the incidence rate, and if it is high enough (say 3-4% or more), we will then develop these sites for future HIV prevention trials.”

An empowerment tool for Indian women
Dr. Chandhiok has been working in this area for almost a decade. In 2003, she received a Fogarty Fellowship at Brown University, where she was exposed to research on microbicides as an HIV prevention tool.  “In early 2000, people thought HIV was going to spread like wildfire in India,” explains Dr. Chandhiok. As a result, the ICMR was looking ahead to find new prevention tools that they could possibly add to the government’s existing arsenal of HIV prevention strategies. As it turns out, the epidemic did not spread as imagined. “HIV is still a big issue in our country, but our numbers are better now… We don’t have a general epidemic. So, given the nature of the epidemic in India, any tools we develop will be for specific populations.”

Dr. Chandhiok explains further, “We talk in terms of a prevention toolbox. We don’t talk about one general tool. The aim is to provide several options that a person could  use through their entire sexual life. So, for example, you have a choice – if you can use a condom, great; if not, then you have the option of using a microbicide also.”

Dr. Chandhiok feels that prevention tools such as microbicides, once their efficacy has been proven and effective products created, could serve to empower Indian women. “As an empowerment tool for women these prevention tools need to be developed.” She explains, “These are very important for us to look at because if a woman, for whatever reason, is unable to negotiate the use of a condom during sex, at least she can have something else to protect herself with—something that can help put her in control.”

Concerns and challenges
Dr. Chandhiok is quick to point out that a lot of this discussion, though, is still theoretical. “At this point, we don’t have enough data to roll out tomorrow. There are still questions to be answered. We’re not at the point of saying we are ready to roll.”

For instance, she explains that oral PrEP, even were its efficacy to be proven, would still run into a huge implementation challenge in India. “In India, we don’t have strong regulation. You could be able to buy an ARV without prescription. So for something like PrEP, which is pill based, you don’t want people using it just like that without a proper prescription or a trained professional administering it and providing proper information and counselling.”

Dr. Chandhiok also feels that because HIV isn’t seen as such a priority issue amongst the majority of the population, adherence issues are another challenge, “Prevention is different from treatment. Only if I perceive myself at risk, only then will I think of preventing it.” And, as Dr. Chandhiok explains, in India most people do not perceive themselves as being at risk – HIV is perceived as a problem relegated to those at the margins of society, commercial sex workers or men who have sex with men. “Basically, for us to be able to roll out something like PrEP, we need government commitment, we need the funds to procure it, and we need a system to reach all the people who require it.” And, as it stands now, all three of these factors remain unclear.

The first and most important hurdle, however, is to prove the efficacy of these new prevention tools, says Dr. Chandhiok. “Only once efficacy is proven, can we even begin to think of all the implementation issues. And as it stands now, the trial results are contradictory; so we are still not too certain about how to proceed.” (Learn more about the various HIV prevention trials here).

Particularly disappointing was the closure of the VOICE trial’s study arm testing tenofovir gel last November, says Dr. Chandhiok. “I’m a little confused because of all the conflicting results. There is no one direction as yet, so we don’t know the clear path ahead. We can’t move forward until we have clear-cut evidence that these tools work.”

Note: The VOICE trial announced on November 25, 2011 the closure of its study arm testing tenofovir gel. The decision was made due to futility – while tenofovir gel was found to be safe, the trial was not able to prove the gel worked to prevent HIV. See the statement from the Microbicide Trials Network  for more information. Previously, the trial had to drop its tenofovir tablet arm due to futility as well. The Truvada tablet arm in the trial is continuing.

Nomita Chandhiok is the Deputy Director General in the Division of Reproductive Health at the Indian Council of Medical Research, the premiere research body of the government of India.



[Content that is linked from other sources is for informational purposes and should not construe a Mapping Pathways position.]

10 February 2012

Cotrimoxazole cost-effective and lifesaving for people starting ART in Sub-Saharan Africa

via Aidsmap, by Carole Leach-Lemens

Achieving full coverage of cotrimoxazole prophylaxis during the first six months of antiretroviral therapy would be a highly cost-effective way of reducing early death among those with advanced HIV infection in sub-Saharan Africa, researchers report in the advance online edition of the Journal of Acquired Immune Deficiency Syndromes.

The researchers developed a decision-analytic model from a health care perspective to compare costs and outcomes. Full cotrimoxazole prophylaxis coverage at an estimated additional cost of $3.29 for each person on ART prevented an additional 22 deaths compared to the base-case scenario (from 94 to 72 deaths per 1000 patients) at a cost of $146.91 for each death prevented over the first six months.

Potential cost savings for specific opportunistic infections (OIs) prevented by cotrimoxazole prophylaxis were also calculated.

Prevention of 45 new malaria episodes per 1000 persons treated would save between $69.95 and $203.32 per case averted, while prevention of 22 severe bacterial infections per 1000 persons would save between $68.62 and $126.71 per case averted. Prevention of four new cases of pneumocystis pneumonia would save between $75.69 and $88.41per case averted.

An intervention is considered very cost-effective by the World Health Organization if the incremental cost per life-year saved is no greater than the GDP per capita; in the case of the poorest countries in Africa this was calculated at $1695 in 2005. This analysis is not strictly comparable because it calculates cost savings in deaths averted.

Over the past decade the increasing availability and access to ART in resource-poor settings has resulted in reductions in AIDS-related deaths.

Yet, in sub-Saharan Africa people continue to present for care at an advanced stage of illness resulting in high rates (8-20%) of early death after starting ART compared to North America and Europe. Common causes of death include tuberculosis, pneumonia and diarrhoeal illnesses.

In North America and Europe it is common practice to give cotrimoxazole prophylaxis to those who present for care with advanced HIV, primarily to prevent PCP. Its use in African settings, however, appears to protect against a wider range of infections and is not restricted to those with advanced HIV.

Recent studies in sub-Saharan Africa, while not randomised, have shown a consistent reduction in death where people on ART got cotrimoxazole compared to no cotrimoxazole, note the authors. In particular cotrimoxazole has been shown to reduce the risk of tuberculosis and of malaria in people taking antiretroviral therapy. A meta-analysis of seven studies shows that cotrimoxazole prophylaxis reduced the death rate in people taking antiretroviral therapy by almost 60%.

Read the rest.


[Content that is linked from other sources is for informational purposes and should not construe a Mapping Pathways position.]

09 January 2012

Apparent declining efficacy in randomized trials: examples of the Thai RV144 HIV vaccine and South African CAPRISA 004 microbicide trials

via AIDS, by O’Hagan, Justin J.; HernĂ¡n, Miguel A.; Walensky, Rochelle P.; Lipsitch, Marca

Recent HIV prevention trials have given hope that a suite of interventions that effectively reduce individuals’ risk of HIV infection will soon be widely available. In two studies, the RV144 and CAPRISA 004 trials, the relative risk of infection increased toward the null value of one over time. The RV144 and CAPRISA investigators interpreted these trends as evidence that the interventions’ effects declined over the study period and suggested that their respective findings may be explained by waning vaccine efficacy and decreasing adherence. Here, we discuss these trends in the trials’ results and note that, in addition to the possible mechanisms cited by the investigators, their apparent waning efficacy may be explained in part by selection bias due to heterogeneity in infection risk, an explanation that has not been considered previously. This bias arises when study participants vary in their susceptibility to infection, for example, because of differences in immune systems or exposure to infection. This can lead to increasing differences in the composition of the study population in each trial arm over time as those at highest risk become infected, and can occur despite comparability between arms at baseline. This issue is termed ‘frailty’ in statistics and demography, in which a large body of literature addresses the matter. We also discuss several methods that can improve understanding of the effects of infectious disease interventions and risk factors by assessing the impact of frailty on results.

Variation in frailty among study participants likely creates trends in the incidence of infection over the course of a study. To understand this phenomenon, consider a theoretical placebo-controlled randomized trial, in which the risk of infection varies among participants. The highest risk individuals in such a trial are expected to become infected earlier, leaving a pool of lower risk individuals at later time points. If the intervention being tested is effective, the decline in the incidence of infection over time will be larger in the placebo arm because these individuals experience no direct protection from the intervention, and so those at high-risk will be quickly depleted, thereby lowering the infection rate over follow-up. However, high-risk individuals in the active arm may remain uninfected due to the protection conferred by the intervention, so the active arm's infection rate will be less affected. Consequently, the time-specific rate ratio for treatment vs. placebo will increase over time from a value of less than one initially to a value that may exceed one later. This phenomenon has also been termed ‘survivor bias’, ‘survivor cohort effect’, ‘crossing of hazards’ and ‘depletion of susceptibles’, and is observed in both chronic and infectious disease research.

Read the rest.


[Content that is linked from other sources is for informational purposes and should not construe a Mapping Pathways position.]

20 June 2011

Understanding the barriers to PrEP uptake


While formulating PrEP strategies, it is imperative that we, the HIV/AIDS prevention community, take into account the target community's concerns. By understanding the possible barriers and coming up with solutions, we can help ensure maximum possible effectiveness.

As per the findings of a study conducted in Peru and published in the International Journal of STD and AIDS, significant barriers among at-risk groups include concerns about cost, efficacy, and side-effects. The study was conducted by a team of researchers from UCLA and Lima, Peru; it included female sex workers, male-to-female transgendered individuals, and MSM.

To know more, check out aidsmap's round-up of the study here and EurekAlert!'s detailed article here.

On a related note, the Mapping Pathways project is also in the process of trying to gather perspectives on these questions from folks in our current focus areas – the US, South Africa, and India. If you’re interested in new ways to prevent transmission of HIV – and want to help shape our project goals and deliverables – we encourage you to take a few minutes and fill in our survey.

Your efforts will be greatly appreciated!


[Content that is linked from other sources is for informational purposes and should not construe a Mapping Pathways position.]