Gene Therapy Offers Hope of Cure for HIV

by: Jeremy Laurance

The Independent UK

12 February 2009

http://www.independent.co.uk/life-style/health-and-wellbeing/health-news/gene-therapy-offers-hope-of-cure-for-hiv-1607227.html



    Doctors have succeeded in ridding a man of the HIV

virus by giving him a bone marrow transplant in what

they claim is the closest treatment yet to a cure for

the disease.



    The remarkable case gives new impetus to the

development of gene therapy for HIV which could

ultimately replace the need for expensive and toxic

antiretroviral drugs. Instead of taking drugs for life,

HIV sufferers might instead have a one-off treatment

that would leave them virus-free.



    The 42-year-old American had been infected with HIV

for a decade. He was treated with antiretroviral drugs

in Berlin, where he lives, for four years to hold the

disease in check, but then developed leukaemia. Since

being given a bone marrow transplant two years ago, he

has not taken antiretroviral drugs to control HIV and

has had no resurgence of either disease. He is believed

to be the longest HIV-free survivor who was previously

treated with antiretroviral drugs. Full details of the

case are published for the first time today in The New

England Journal of Medicine. An editorial in the journal

says it "places further emphasis on gene therapies" for

HIV, adding: "The case paves the way for innovative

approaches that provide long-lasting viral control with

limited toxicities for persons with HIV infection."



    The man's treatment began with a search by doctors

at Berlin's Charité Hospital for a bone marrow donor

with a genetic resistance to HIV. One of the strangest

features of the disease is the way some people who have

been exposed to the virus on many occasions remain

uninfected. Twenty years ago, it was noticed that

certain prostitutes in Nairobi remained uninfected

despite exposure to the virus through thousands of

sexual contacts.



    It has since emerged that some people carry a

mutation of a gene (CCR5) that confers protection

against HIV. In Western populations an estimated one to

three per cent have the mutation.



    Dr Gero Hutter, a haematologist at the Berlin

Charité Hospital, and colleagues tested 61 potential

donors before they found one with the CCR5 genetic

mutation, who agreed to the operation.



    The American recipient of the transplant, who runs a

holiday rentals business in the German capital, has

undergone regular checks in the two years since the

treatment. The doctors have tested his bone marrow,

blood and tissues and found no sign of HIV. "For as long

as the viral load remains undetectable, this patient

will not require antiretroviral therapy," they say in

the journal.



    Speaking to The Independent yesterday, Dr Hutter

said there had been several previous reports of patients

being virus-free following treatment but none to compare

with the latest case. "The difference is that in our

patient we had a plan. It was not an accident," he

added. "It is the longest time someone who has had

antiretroviral therapy and stopped has lasted without

the virus rebounding. Normally it rebounds within weeks.

It is the closest we have come to a cure."



    Dr Hutter said a bone marrow transplant would be too

risky as a routine treatment for HIV and too difficult

to find donors with the right genetic make-up. But a

modification of the approach using gene therapy to

render a patient HIV-resistant could work, he said.



    Even a costly treatment could be worthwhile. The

price of treatment with antiretrovirals in Europe is

_70,000 to _80,000 (£63,000 to £72,000) a year compared

with a one-off cost of _20,000 to _30,000 for a bone

marrow transplant.



    Dr Hutter said: "When I started in medicine, HIV was

completely untreatable. Now the situation has changed

completely. Perhaps our case is a glimpse of hope for

the future."



    Professor Jay Levy, an AIDS specialist at the

University of California, and author of the US journal's

editorial, said claims that the patient had been cured

of HIV would be premature because of the virus's

capacity to hide in other parts of the body including

the brain, gut, liver and lymphatic system, from which

it could always re-emerge.



    "Nevertheless, the results ... provide further

encouragement for those examining approaches to

treatment that reduce CCR5 expression in persons with

HIV infection," he writes. In 2007, an estimated two

million people died from AIDS and 2.7 million were newly

infected with HIV.



    25 Years of Research: The HIV Virus



    When the discovery of HIV was announced in 1984, US

politicians predicted that a cure for AIDS would be

found within five years, but it is still a distant

prospect.



    Over the past 10 years, a cocktail of aggressive

antiretroviral drugs has been developed to help keep the

effects of the disease at bay. Eliminating it has proved

far more difficult because of the virus's unique nature.



    HIV integrates itself into an infected person's DNA

and attacks the cells the immune system sends to attack

it. Once infected, these T-cells take the virus deeper

into the body. Gene therapy is a new approach that

harnesses the natural resistance to HIV shared by 3 per

cent of people.



    Experts hope that by tweaking a sufferer's DNA, they

can achieve "long-lasting viral control."



_____________________________________________