Friday, December 30, 2016

Scientists caution public expectations on 2016 HIV cure breakthrough research

By Esther Nakkazi

In the year 2016, there was so much excitement about cure research opportunities from the ‘functional cure’ for HIV. However, scientists cautioned the public about high expectations.

Scientists at the National Institutes of Health (NIH) and Emory University in an experiment induced sustained remission of SIV in animals, which if translated to humans could mean that there is a possibility of having people on anti-HIV drugs sustain suppression of the virus and get off of the drugs. 

This is called sustained HIV remission or a ‘functional cure’ which is not a cure but an outcome of a treatment that induces prolonged, undetectable levels of HIV viremia without the daily anti retroviral treatment (ART).

I attended the biennial HIV Research For Prevention conference (HIVR4P 2016) held 17-21 October in Chicago, USA and Anthony Fauci, an immunologist who heads the U.S. National Institute of Allergy and Infectious Diseases (NIAID) and had carried out a landmark research about it explained that some people call it a cure others sustained remission.

Fauci with his team carried out an experiment, which involved infecting monkeys with SIV, the simian form of HIV. The research was published in the Oct. 14 issue of the journal Science.

According to a press release from the National Institutes of Health (NIH), the investigational treatment regimen consisted of 90 days of ART combined with 23 weeks of treatment with a laboratory-derived monkey antibody against a cellular receptor called alpha-4-beta-7 (a4b7) integrin. 

This antibody is similar to the human drug vedolizumab, which is approved by the U.S. Food and Drug Administration (FDA) for treating ulcerative colitis and Crohn’s disease.

The animals’ immune systems suppressed the virus to undetectable levels for as long as 23 months and the regimen led to the near-complete replenishment of key immune cells that SIV had destroyed, something unachievable with antiretroviral therapy (ART) alone.

Way Forward: 
While speaking to the press at the HIVR4P 2016, Fauci said there was so much that they (scientists) do not know, especially the mechanism, but what was loud and clear was the effect. So they decided to start a study in humans. 

The NIAID team will start an FDA approved study with 15-25 people with this profile; HIV infected, 18-65 years old, stable with controlled viremia, CD4 count of 450+, not pregnant and generally with a relatively healthy immune system.

They will get treatment interruptions of combined short-term vedolizumab treatment and ART for 30 weeks. Thereafter, both will be stopped and they will be followed for at least seven months.

The study investigators hope that what happened in the monkeys suppressing SIV replication will be repeated in humans - basically control the virus levels in the absence of ART and the antibody - so the immune system controls the virus in the absence of ART. Preliminary results are expected by the end of 2017 or beginning 2018.

“If we discontinue therapy in the 15 and 4 of them do not rebound that is the best anybody has ever seen,” said Fauci. Most patients immediately rebound after discontinuing therapy.

He also cautioned on public expectations. “Even if it is dramatic in animals we do not want to take a human who is infected and do more harm than good that is why we are starting off with a small phase I study whose primary goal is safety.”

African scientists comments about the 'functional cure' research; 

I interviewed some leading African scientists who attended the HIVR4P 2016 about the 'functional cure' research. Here is what some of said about it.   

'Cautious hopeful'. “It is exciting that we are beginning to get signals. However, these are monkey studies but bring hope. Over the years, we have learnt that people and animals are different so I would say -cautious hopeful, said Nelly R. Mugo, a gynaecologist and a principal research scientist at the Kenya Medical Research Institute (KEMRI).

'Surprising result.' “It is a very surprising result and I think everybody recognises that. I can say we do not really know how it is working, obviously we have some idea but we do not really know the mechanism,” said Lynn Morris the head of the HIV Virology laboratories at the National Institute for Communicable Diseases (NICD) in South Africa.

'It is too early.' “It is exciting because it offers another opportunity. If it is confirmed by other studies it will be quite exciting because people might be able to come off ART. But I think It is very early,” said Thumbi Ndung’u an immunologist and Scientific Director of the HIV Pathogenesis Programme at the University of KwaZulu Natal in South Africa.

Studies in Africa

Many HIV studies are done in Africa and Morris hopes that if a study is done in the US as Fauci promised there will be interest in doing it in South Africa.

In her opinion, from a cure perspective it is going to be a simple study do to. "The point is it is a licensed product so let us not waste time figuring out the mechanism let us just try it. If it works we can figure out if it really prevents rebounding then we can try and figure out how we can do this,” said Morris.

“It is exciting because integrins unlike the virus are the same. The big issue is going to be cost,” said Morris referring to monoclonal antibody therapies which are extremely expensive.

“But cost should never ever be used as a barrier to doing things because if there is a need the cost is a flexible controlled by demand. People should not come with negative things like cost I think the studies have got to be done and if they work people will find a way around the obstacle,” she said.

If the drugs work they will be re-licensed for HIV and it is envisaged that there will be a different pricing structure and there will be mass production. 

Over 37 million people according to UNAIDS need ART. Currently, they are only produced for the niche market for people suffering from inflammatory bowel disease. 

“It is yet another piece of evidence that we are moving closer to a situation where HIV is like cancer where it can be treated and does not come back in a long time,” Thumbi Ndung’u said.


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