HIV Weekly - 13th November 2013

HIV virulence

HIV may be evolving and becoming less virulent, research presented to a recent conference suggests.

People living with HIV who are doing well on antiretroviral therapy can have a normal life expectancy. But, if left untreated, infection with HIV is usually eventually fatal. This is because the virus gradually damages the immune system, meaning that a person becomes vulnerable to a number of potentially life-threatening cancers and infections – so-called 'opportunistic infections' – that they would otherwise be able to fight off.

The pace of HIV disease progression varies between individuals. But, without treatment and care, most people will develop opportunistic infections and die between eight and twelve years after first becoming infected with HIV.

Antiretroviral treatment has transformed the life expectancy of people with HIV, and on an individual level, treatment and care can halt disease progression and allow the immune system to recover. But researchers have also found some intriguing evidence that HIV itself may be becoming less virulent.

This is because of the way the virus is evolving to respond to a type of HLA (human leukocyte antigen) genes.

Studies conducted in southern Africa suggests that this means HIV is less “fit” and there’s been a recent increase in the proportion of people who maintain a high CD4 cell count and low, even undetectable, viral load without the need for antiretroviral therapy. People with these characteristics are often referred to as ‘elite controllers’.

It’s hoped that this will help in the research for an effective vaccine for HIV.

You can read this news story in full on aidsmap.com, along with other news reports from the AIDS Vaccine 2013 conference, where this was presented. An audio recording of the presentation is available on the conference website.

Treatment for tuberculosis (TB)

Worldwide, tuberculosis (TB) is the single biggest cause of serious illness and death among people with HIV. In most cases, TB can be cured by treatment with a combination of antibiotics. This treatment usually last for six months and is in two phases. For the first two months treatment consists of four drugs and is then followed by four months of treatment with two drugs.

Although TB is usually cured by treatment, many people find it difficult to take the treatment as prescribed or to complete the whole course of treatment, which is necessary to get rid of all the TB bacteria. This can lead to the development of drug-resistant TB, and this is an increasing problem around the world.

Researchers are therefore trying to find new anti-TB drugs or ways of shortening the time it is necessary to take TB treatment. 

Ethambutol is one of the four drugs taken during the first two months of TB. Researchers wanted to see if the total duration of TB therapy could be shortened to four months by replacing ethambutol with a drug called gatifloxacin.

At the end of treatment, people in the gatifloxacin arm of the study had slightly better outcomes than people taking the standard TB therapy containing ethambutol. But longer-term outcomes were clearly inferior for the people treated with gatifloxacin.

The researchers were nevertheless encouraged that gatifloxacin didn’t cause a disturbance in heart rhythm, which has been associated with some other anti-TB drugs currently in development.

For more information on HIV & TB in the UK, you may find our HIV & TB booklet helpful, and The Truth About TB website, produced by TB Alert. Our email newsletter for people working in resource-limited settings regularly covers TB research and you can find a complete archive of these newsletters at www.aidsmap.com/hatip

Hepatitis B and hepatitis C

Many people with HIV also have hepatitis B (HBV) and/or hepatitis C (HCV). This is sometimes referred to as ‘co-infection’. Liver disease caused by hepatitis is a major cause of serious illness and death in people with HIV and hepatitis co-infection.

Both hepatitis B and hepatitis C can be treated. A conference in Washington last week heard about recent developments in hepatitis treatment.

The aims of hepatitis B therapy include slowing the pace of liver disease caused by the virus and clearance of the infection.

Research presented to the conference showed that therapy with tenofovir or entecavir reduced, but did not eliminate, the risk of liver cancer for people with chronic hepatitis B. The participants in the study had liver cirrhosis caused by hepatitis B.

There’s a lot of research into new hepatitis C treatments. Some types of hepatitis C are harder to treat, and cure rates can be lower in people who also have HIV. Current hepatitis C treatment can also have unpleasant side-effects. However, there are many new drugs and treatment strategies in development, which offer hope to people whose hepatitis has not yet been successfully treated and cured.

The conference heard about some of these new treatments.

A major development in hepatitis C treatment has been the development of direct-acting antiviral drugs (DAAs, that is, drugs that attack the hepatitis C virus itself, unlike current standard treatment of interferon and ribavirin). These are effective as they can prevent the hepatitis C virus reproducing and quickly lead to it being eradicated from the blood and the liver.

A number of studies presented to the conference showed that use of combinations of DAAs or treatment with a DAA in combination with pegylated interferon and ribavirin improved treatment outcomes:

• Daclatasvir and asunaprevir cure 85% of HCV genotype 1b patients.
• Fixed-dose sofosbuvir/ledipasvir with or without ribavirin cures most patients with HCV genotype-1.
• Sofosbuvir taken before or after liver transplant reduces risk of liver cancer for patients with HCV.

You can find all our news reports from ‘The Liver Meeting 2013’ on our conference webpages: www.aidsmap.com/conferences