News (Updated June 22, 2008)
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By MARIA CHENG, AP Medical WriterFri Jun 20, 7:07 AM ET
Doctors have long suspected that people with herpes are more likely to catch HIV. So they thought that by treating herpes, they could also cut a person's HIV risk. But a new study that tested this strategy found the assumption may have been wrong.
"It's a significant, disappointing finding," Francis Ndowa, coordinator of the sexually transmitted infections control team at the World Health Organization, said in an interview.
Ndowa was not connected to the research, published Friday in the medical journal The Lancet.
The finding may spark a rethinking of HIV prevention strategies in Africa, where controlling sexually transmitted diseases such as herpes is usually part of general AIDS prevention plans.
Researchers tracked more than 3,000 men and women infected with herpes in Africa, Peru and the United States. Roughly half were treated with aciclovir, an antiviral that stops herpes ulcers.
After a year and a half, the scientists found that 75 people out of the 1,581 who had been receiving aciclovir were later infected with HIV. Of the 1,591 people who received placebo pills, 64 contracted HIV.
In the trial, researchers chose participants who had herpes and who faced similar risks of getting AIDS. The study also questioned the participants during monthly visits about risky sexual behavior with their recent partners.
The study was paid for by the United States' National Institute of Allergy and Infectious Diseases, other U.S. government institutes, and by GlaxoSmithKline PLC, which sells aciclovir as Zovirax.
A small study in Tanzania last year also suggested that treating herpes didn't help reducing HIV susceptibility.
But that doesn't necessarily mean that the theory of treating herpes to avoid HIV is incorrect, experts said.
"It's probably likely that we need considerably more potent interventions than we have," Connie Celum, a professor of global health and medicine at the University of Washington who led the Lancet study, told The Associated Press.
Experts said there was a complex relationship between the two viruses that is still not entirely understood.
When herpes ulcers erupt, that draws white blood cells to the skin to fight the virus. Unfortunately, those white blood cells also have receptors for HIV.
Ndowa said it was possible that even without the telltale ulcers, herpes might have lingered while patients were taking the aciclovir, allowing HIV to gain a foothold.
In an accompanying commentary in the Lancet, Ronald H. Gray and Maria J. Wawer of Johns Hopkins University said it was questionable whether controlling sexually transmitted infectious could work to prevent HIV.
"It is time to reassess the hypothesis and to adjust prevention policy accordingly," they wrote.
But Ndowa and Celum said the strategy of fighting herpes to prevent AIDS might work, if a different dosage or more powerful drug was tried.
"We don't exactly know why this didn't work, but this approach still has potential," Ndowa said. "Maybe it was just too much to expect from a tablet taken twice a day that it could be effective against HIV."
The stock rose $1.22, or 2.3 percent, to $54.67 in afternoon trading. Shares of the Foster City, Calif.-based company are trading near their 52-week high of $56.95.
"We expect Gilead's HIV franchise to continue to meet or beat Wall Street estimates, and thus believe the stock's premium valuation is sustainable over the near to intermediate term," wrote Deutsche Bank-North America analyst Mark Schoenebaum, initiating a "Buy" rating on the stock in a note to investors.
The bulk of Gilead's sales come from HIV treatments, with $1.59 billion from Truvada and $903.4 million from Atripla in 2007. In all, the company had revenue of $4.23 billion in 2007 and expects between $4.7 billion and $4.8 billion in 2008.
Schoenebaum raised his second-quarter profit forecast to 49 cents from 48 cents per share, while analysts polled by Thomson Financial expect profit of 48 cents per share. He set a price target of $63.
Meanwhile, RBC Capital Markets analyst Jason Kantor reaffirmed a "Outperform" rating with a $58 price target on Gilead. He expects the company to raise its full-year outlook when second-quarter results are released.
"Our current sales forecast for the first half of 2008 is already halfway to the lower end of guidance, and Gilead has increased guidance on its second quarter call in each of the last three years," he wrote in a note to investors.
Gilead's HIV drug franchise could gain market share at the expense of competing drugs because of recent study data showing HIV drugs containing abacavir can have dangerous side effects for certain patients. GlaxoSmithKline's Epzicom contains abacavir.
"The effects of the abacavir safety and efficacy concerns could be even more pronounced in Europe where there is greater abacavir use and where some treatment guidelines have already been changed," said Piper Jaffray analyst Thomas Wei, reaffirming a "Buy" rating.
Tuesday June 17, 12:20 pm ET
The OraQuick Advance is a test that rapidly screens saliva and blood samples for antibodies to both HIV-1 and HIV-2. The company said Monday there always is a small possibility of false positive results, but maintains that the test is 99.8 percent accurate, based on nationwide use in more than 400 testing sites.
New York City Health Department officials recently stopped using OraQuick Advance at its 10 STD clinics as an oral test, citing specificity issues, after reporting "a somewhat elevated number of discordant test results from October 2007 through April 2008." Officials still are using it to screen blood samples.
Orasure said it is working with the NYC Department of Health and the Centers for Disease Control and Prevention to better understand the performance at the STD clinic sites.
Cowen analyst Sara Michelmore said Orasure was in communication with NYC officials prior to their decision to suspend oral testing, but were unfortunately unsuccessful in their attempt to root out the problem. The investigation is ongoing and the CDC also is probing the matter, with the agency considering publishing an alert for health officials in its weekly report.
"News of the performance issues could negatively impact OraQuick sales near term (although the sites involved now are immaterial), and add to a challenging near-term financial outlook of OSUR in front of key new product launches from the company's pipeline," Michelmore said in a note to clients. She maintained a "Neutral" rating on the stock.
But Lazard Capital Markets analyst Jeffrey Frelick said "you cannot necessarily rule out operator influence" in reviewing the higher-than-usual false positives, given the test's overall nationwide accuracy and the volume of 5,000 tests per month.
"We believe that following its investigation, the CDC will continue to endorse oral collection technology for HIV screening," Frelick said in a note to investors, backing a "Buy" rating and $12 price target on the stock. "The OraSure test continues to perform above the FDA threshold, within its expected performance range, and positive tests are always confirmed, regardless of the methodology or collection mode."