News (Updated December 21, 2008)

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HIV infects women through healthy tissue: U.S. study

By Julie Steenhuysen Julie Steenhuysen Wed Dec 17, 12:27 pm ET

CHICAGO (Reuters) – Instead of infiltrating breaks in the skin, HIV appears to attack normal, healthy genital tissue, U.S. researchers said on Tuesday in a study that offers new insight into how the AIDS virus spreads.

They said researchers had assumed the human immunodeficiency virus, or HIV, sought out breaks in the skin, such as a herpes sore, in order to gain access to immune system cells deeper in the tissue.

Some had even thought the normal lining of the vaginal tract offered a barrier to invasion by the virus during sexual intercourse.

"Normal skin is vulnerable," said Thomas Hope of Northwestern University 's Feinberg School of Medicine said in a telephone interview.

"It was previously thought there had to be a break in it somehow," said Hope, who is presenting his findings at the American Society for Cell Biology meeting in San Francisco .

He said until now, scientists had little understanding of the details of how HIV is transmitted sexually in women.

Hope and colleagues at Northwestern in Chicago and Tulane University in New Orleans developed a new method for seeing the virus at work. They studied newly removed vaginal tissue taken from hysterectomy surgeries, and introduced the virus which carried fluorescent, light-activated tracers.

Then they watched under a microscope as the virus penetrated the outer lining of the female genital tract, called the squamous epithelium. They also observed this same process in non-human primates.

In both cases, they found HIV was able to quickly move past the genital skin barrier to reach immune cells, which the virus targets.

Hope said the study suggests the virus takes aim at places in the skin that had recently shed skin cells, in much the same way that skin on the body flakes off.

The finding casts doubt on the prior theory of the virus requiring a break in the skin or gained access through a single layer of skin cells that line the cervical canal.

And it might explain why some prevention efforts have failed. Hope said one clinical trial in Africa in which women used a diaphragm to block the cervix had no effect at reducing transmission of the virus. Nor have studies of drugs designed to prevent lesions in genital herpes proven effective.

Hope said the findings emphasize the need for treatments such as a vaccine to prevent infection.

And it makes clear the need for the use of condoms, which are highly effective at preventing infection.

"People need to remember that they are vulnerable," Hope said. "The sad part is if people just used a condom, we wouldn't have this problem," he said.

In the United States , HIV is mostly passed among men who have sex with men. Females account for 26 percent of all new HIV cases in the United States , according to the U.S. Centers for Disease Control and Prevention.

Globally, HIV is more commonly spread by heterosexual sex. The virus has infected 33 million people globally and has killed 25 million.

Gilead sues Teva over HIV drug patent

Monday December 15, 7:48 am ET

Gilead sues Teva for patent infringement on blockbuster HIV treatment Truvada

FOSTER CITY , Calif. (AP) -- Biotechnology company Gilead Sciences Inc. said Friday it filed a patent infringement lawsuit against Teva Pharmaceutical Industries Ltd. over the generic drugmaker's move to make a version of the blockbuster HIV treatment Truvada.

Gilead said Teva's plan to make a generic version of the drug would infringe on two patents covering a component of Truvada. The drug is protected by 10 patents, Gilead said. The Foster City , Calif. , company said it filed the lawsuit in U.S. District Court in New York .

In November, Israel-based Teva asked the Food and Drug Administration to approve its generic version of Truvada. In that request, it said two of the 10 patents protecting Truvada are invalid, unenforceable, or would not be infringed if Teva is allowed to market its own version. Gilead has said the two patents in the lawsuit aren't set to expire until 2021.

Both patents concern Emtriva, one of the two components of Truvada. The other component is a separate Gilead drug called Viread. Emtriva and Viread are also key components in the three-in-one HIV treatment Atripla, along with Bristol-Myers Squibb Co.'s Sustiva.

Truvada sales reached $549.1 million during the third quarter, making up 40 percent of the company's revenue during that period.

The lawsuit triggers a halt in the FDA's regulatory process. It will not approve Teva's generic Truvada for up to 30 months or until a court rules on the validity of the patents.

Aurobindo Pharma gets first US nod for efavirenz tab

Reuters MUMBAI, Dec 17 - Drug maker Aurobindo Pharma Ltd <ARBN.BO> said on Wednesday the U.S. Food and Drug Administration has tentatively approved its application to sell efavirenz tablets in the United States .

The drug is used to treat human immunodeficiency virus or HIV infections in combination with other anti-retrovirals.

The approval is for 100 mg tablets, the company added in a statement.

Lemur virus gives clues to evolution of HIV

Source: IRIN

ANTANANARIVO , 16 December 2008  - A squirrel sized lemur from Madagascar has given scientists new evidence about the origins of the HIV virus and opened up promising new avenues for investigation.

Robert Shafer, a senior author of the research, told IRIN/PlusNews that the discovery "is one of the most important missing links" required for understanding the evolutionary history of HIV-related viruses.

It is widely believed that the two strains of HIV prevalent in humans, HIV-1 and HIV-2, were passed on by primates from Africa , and that these primates have harboured the disease for a million years at the most. But the discovery of a virus related to HIV in the genetic make-up of the tiny grey mouse lemur, found only in Madagascar , has turned these beliefs on their head.

The new findings, published in the Proceedings of the National Academy of Sciences on 1 December, suggest that lentiviruses, the family of viruses to which the HIV-1 and HIV-2 belong, have been present in primates for at least 14 million years. That was the last time the Indian Ocean island of Madagascar was linked to mainland Africa , allowing the disease to pass to lemurs.

"Our discovery means that primate lentiviruses have been present in Madagascar historically and may still be circulating there," Robert Gifford, an infectious disease researcher at the Stanford School of Medicine and lead author of the research, told IRIN/PlusNews. "Since Madagascar has been very isolated throughout evolutionary history, it's not clear how we could have these viruses present both there and in Africa , unless they are in fact many millions of years old."

Scientists now believe that lentiviruses could be at least 50 million years old, and that they may be found in primates throughout the world.

More than 25 million people across the world have died of AIDS-related illnesses since the HI virus was first identified in the United States 27 years ago. Two-thirds of the 33 million people infected with HIV globally live in sub-Saharan Africa, but Madagascar 's HIV prevalence rate has so far remained below 1 percent. The prevalence of syphilis and other sexually transmitted diseases, however, suggest that the virus could spread rapidly.

The recent findings from Stanford University are unlikely to radically change the course of research into HIV and AIDS in the short term, but are expected to have a major impact on scientists' broader understanding of the virus.

"If we are ever going to properly understand the relationships between lentiviruses and disease, assess the risk of new epidemics occurring, and harness the body's natural defences to prevent and control HIV infections, we need to establish the proper ecological and evolutionary contexts," Gifford said.

He described the lentivirus material found in the genetic make-up of the grey mouse lemur as "molecular fossils" that show how viruses looked hundreds of thousands or even millions of years ago. This is important, as it helps scientists understand the functions of different genes within a virus, and to assess the limits of virus adaptation and potential vulnerabilities - information that could be used to help develop new ways to prevent and treat infections in humans.

However, Gifford warned that there was still a long road ahead. "Like many things in science, our findings raise as many questions as they provide answers," he said. "But the important thing is that they reveal something new and completely unexpected about the evolutionary relationship between primates and lentiviruses."

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