HIV and AIDS in 2012
March 2012
Will the world be able to afford the vast expense of treating AIDS into the future?
By 2016, it is estimated that it will cost 22 billion dollars globally to keep the 33 million people around the world with HIV on lifelong treatment.
The Burnet Institute’s Co-head of the Centre for Virology and world leading HIV researcher, Professor Sharon Lewin says the world might not be able to provide that ongoing level of support, especially in light of the UN Global Fund cutting their 2012 programs due to a two billion dollar shortfall.
“If we could identify all patients who are HIV-infected and treat all of them with anti-HIV drugs, this will reduce the number of new cases and could potentially one day eliminate HIV. The challenge is to find people who don’t know they are infected and encourage them to get tested so they can start treatment. There is a lot of good evidence now that if you treat someone with HIV you can reduce their infectiousness by 96 per cent,” Professor Lewin said.
“There is a big push now to use treatment as a prevention strategy for HIV. The more people we treat, the better for them and the community. The emphasis over the next few years will be convincing government that funding access to treatment now will be an investment in the future.”
However, Professor Lewin acknowledges that we’re in an environment of competing priorities including malaria, tuberculosis, poverty and maternal health and in times of increasing financial difficulty.
“Governments face very difficult decisions about how much money they give to foreign aid and where they invest it. Saying that, there is no doubt that the HIV virus is a major burden on any health budget,” she said.
Professor Lewin states that in Australia we tend to start treatment earlier on those infected compared with most other countries. The real challenge is in low-income countries where people often don’t get tested until they are sick, which is too late.
While modern drugs for HIV may have saved millions of lives, these treatments come at a high cost. The most advanced treatments now available, combination anti-retroviral therapy (cART), is a life-long therapy and providing these treatments globally – particularly to low-income countries where the need is high – costs national health budgets millions of dollars each year.
If a person stops the drugs, the virus comes straight back. A person receiving cART remains at increased risk of other ageing related diseases such as diabetes, heart disease and early onset of dementia. Patients taking anti-HIV drugs still have a reduced life expectancy.
Both researchers and patients alike thought a cure was imminent when cART was first introduced in the mid 1990s. Professor Lewin talks of a feeling of hope at the International AIDS Conference in Vancouver in 1996, where the results of the very first trials of cART were announced. The treatment rapidly stopped the virus from infecting new cells and the amount of virus in blood plummeted to undetectable levels within weeks of taking the drugs. It was initially assumed that prolonged treatment would lead to eradication of the virus altogether.
But it was not to be. Within weeks of stopping cART, HIV mysteriously re-emerged in the patient’s blood. The hope for finding a cure for HIV became a pipe dream; many people began to question the efficacy of spending so much time and money on something that seemed impossible.
“Instead, people focussed on developing better drugs, getting the drugs to countries that were in greatest need and developing other forms of prevention… and there have been some spectacular successes in each of these areas of research,” Professor Lewin explained.
But not everyone lost hope of a cure, and with every knock-back researchers have received, their understanding of where the virus hides on treatment has increased. The surprise re-emergence of the virus in patients receiving cART treatment, while disappointing, sparked a new line of questioning for researchers –where had these seeds of the virus come from?
In 1999, researchers showed that reservoirs of latent HIV virus was the problem – that is, that HIV virus can lie dormant in the cells of patients for long periods of time, remaining unaffected by cART. The virus can then reawaken once treatment has been interrupted and start replicating again.
While there are many cells that can harbour latent HIV virus, most of the latent virus is in ‘resting memory’ CD4 T-cells. The long life of these cells, combined with a tight control of HIV expression, make these cells the ideal hiding place for the virus.
Understanding the basic mechanisms of how HIV latency is established and maintained in resting memory CD4 T-cells is paramount to developing therapeutics that may potentially lead to a cure.
While researchers have recognised HIV latency since the late 1990s, what has not been understood is the pathway the virus uses to enter the resting cells. There is also a great need to find ways to eliminate latency once it is established.
After more than five years’ work, Professor Lewin and fellow Burnet Institute researcher Dr Paul Cameron, along with their team, have recently identified how HIV latency is established in resting memory CD4 T-cells. They have shown that a family of proteins, called chemokines, that guide resting cells through the blood and into lymph node tissue, ‘unlock the door’ and allow HIV to enter and set up a silent infection.
Understanding this mechanism is a significant breakthrough, and will enable new treatment options to be developed which could block latent infection. It may also allow researchers to find new treatments to flush out latent virus already inhabiting resting cells. This is of great importance, as most people on cART treatment today will already have latently infected resting memory CD4 T-cells.
Cure, vaccine or treatment?
While Professor Lewin dedicates her career to research into an HIV cure, she believes the most effective global response is the combination of working towards a vaccine, cure and access to treatment. Evidence suggests treatment is effective and prevents transmission so there is already a very powerful tool to reverse the epidemic – that is testing and treating people early.
“Most infectious diseases have been eliminated primarily through vaccination and a cheap and effective vaccine will still be a very important part to ultimately end the AIDS epidemic. But because we have all these other ways to prevent HIV now, there might be less pressure to develop the ‘perfect’ vaccine. A vaccine might be one part of a multi-pronged strategy to eliminate new infections,” Professor Lewin explained.
“So I don’t think it’s one or the other – cure or vaccine. Access to treatment has to be a top priority but if we don’t invest in new ways to manage people with HIV then we’re going to be stuck in this paradigm of life-long treatment for everyone which is expensive – it’s not getting any cheaper – it’s probably the cheapest it’s ever going to get now.”
She said pooling research resources globally is a sound approach and that the vaccine research world has demonstrated that this strategy is effective through the establishment of large, international networks of collaborative research teams.
“In many ways that’s what we would like to mimic in the HIV cure area of research and there are already steps towards that with the Martin Delaney co-laboratories, funded through the American National Institutes of Health (NIH),” Professor Lewin said.
Professor Lewin is one of a group of seven researchers (and the only Australian) awarded one of those NIH grants, part of one of the biggest investments into HIV research in history.
The NIH has funded USD $70 million and is about to fund another USD $30 million to establish collaborative groups that work with each other and work with industry to find a cure for HIV – or a way to stop the need for life-long treatment.
“This funding will, without a doubt, accelerate the path to hopefully one day finding a cure for HIV. It’s a huge amount of money with the capacity to apply for more. The pressure is on to use the money wisely, do some great science and hopefully find a cure. It’s a unique opportunity and we intend to make the most of it,” Professor Lewin said.
International AIDS Conference 2014 in Melbourne
The world’s largest HIV and AIDS conference is coming to Melbourne in 2014 shining the spotlight on the epidemic in the Asia – Pacific region as well as the world-leading research being conducted in Australia.
The International AIDS Conference (AIDS 2014) is held every two years and attracts 25,000 of the world’s leading scientists, healthcare providers, journalists and political, community and business leaders.
Professor Lewin was named local chair of the conference and says Australia has been a global leader in improving diagnosis, treatment and prevention of HIV and AIDS since the virus was discovered in the early 1980s.
“Australia has punched well above its weight given we have such a low prevalence of the virus but we’ve made a major impact globally in work that’s being done in the areas of public health and prevention, clinical management and trials and basic science discoveries,” Professor Lewin said.
“We are a small country with a small budget for science and we have few people with HIV but we’ve made a very significant contribution to the global response.”
Professor Sharon Lewin, an infectious diseases physician and basic scientist, is Co-Head of Burnet Institute’s Centre for Virology, Director of the Infectious Diseases Unit at The Alfred Hospital and Professor of Medicine, Monash University and National Health and Medical Research Council (NHMRC) Practitioner Fellow.
Professor Lewin is in charge of three main projects under the National Institutes of Health (NIH) funding boost:
• To try and find a better way to track latently infected cells in patients on anti HIV drugs.
• To use the model of infected sleeping cells that her lab recently developed to screen new compounds that can wake persistent virus.
• A clinical trial she is leading, looking at an existing cancer drug and how it might work on persistent virus in patients on c-ART.
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