Kaisernetwork.org (Washington, DC)
9 July 2008
Science & Medicine
Biotech Firm GeoVax Labs Seeking FDA Approval To Launch Phase II Trials of HIV Vaccine Candidate
The Atlanta-based biotechnology firm GeoVax Labs on Tuesday announced that it is seeking FDA approval to launch Phase II clinical trials of its experimental HIV vaccine this fall, the Atlanta Journal-Constitution reports (Hendrick, Atlanta Journal-Constitution, 7/9).
GeoVax is developing the experimental HIV vaccine in collaboration with Emory University, CDC and NIH. According to Emory officials, a prototype of the vaccine provided long-term protection against development of AIDS in nonhuman primate studies conducted more than three years ago at the Yerkes National Primate Research Center in Atlanta (Kaiser Daily HIV/AIDS Report, 5/8). According to Robert McNally, president and CEO of GeoVax, during one study that involved two monkeys given a simian version of the experimental vaccine, conventional therapy was stopped after six weeks and the vaccine "kept the viral load in check." He added that there "was a 100-times reduction in the viral load on one animal and a thousand-times reduction in the second animal. ... This is significant because it is suppressing AIDS in monkeys, and that's what we are trying to do in people." McNally noted that the "vaccine controlled the infection even in the absence of drugs." Based on those results, GeoVax started "planning for a therapeutic trial in infected and drug-treated humans," McNally said. He added, "The intent of therapeutic vaccination is for the vaccine to control HIV virus levels in infected individuals to very low levels, thus blocking the development of AIDS."
According to the Journal-Constitution, the proposed trial -- which will be conducted by NIH and supported by the HIV Vaccine Trials Network -- will involve 225 "healthy volunteers" from the U.S. and South America. McNally said the purpose of the study is to "further evaluate the safety and immunogenicity" of the vaccine candidate. He added that the company's goal is to have a therapeutic vaccine approved by FDA that would reduce the amount of antiretrovirals needed by people living with HIV to control its spread and the development of AIDS.
Harriet Robinson, the company's co-founder and senior vice president of research and development, said she had not "anticipated the extent of vaccine control that was achieved in the already infected nonhuman primates," adding the results are "highly promising." Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition, said that the GeoVax primate study is good news but that it is only "one tiny step along the way" (Atlanta Journal-Constitution, 7/9).
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Women Who Use Microbicides, Still Contract HIV Could End Up With Fewer Treatment Options Because of Resistance, Study Finds
[Jul 09, 2008]
Women who use microbicides in an effort to protect themselves from HIV could end up with fewer treatment options if they contract the virus because of possible drug resistance, according to a study published Monday in the Proceedings of the National Academy of Sciences, Reuters reports.
For the study, Sally Blower of the University of California-Los Angeles and David Wilson of the University of New South Wales used data from ongoing trials of microbicides, along with what is known about how HIV develops resistance to existing medicines and how consistently people use drugs and condoms. If an eventual microbicide was not 100% effective and if women did not use it consistently, then a certain percentage of women could contract HIV, according to the researchers' model. Some of these women would continue using the microbicide but not adhere to antiretroviral combination therapies and, thus, would develop resistance, the researchers said (Fox, Reuters, 7/8). According to Blower, trials that remove HIV-positive women most likely will not show how a microbicide could contribute to resistance. "Ethically, it's a good strategy to take infected women out of the microbicide trials," Blower said, adding, "But when you use microbicides as a public health intervention, some women will get infected without being diagnosed and will probably develop resistance to the drug in the microbicide" (Bloomberg/Long Island Newsday, 7/7).
According to Blower and Wilson, drugs used in a microbicide can be absorbed into the body through the vaginal wall and could cause HIV to mutate. They added that this is possible especially in circumstances when people such as commercial sex workers fail to regularly use microbicides (Reuters, 7/8). In addition, prevention trials that halt the use of microbicides for women who have become HIV-positive could allow risky products to enter the market, the researchers said.
Rowena Johnston, director of research for the American Foundation for AIDS Research, said the study's findings are particularly "disturbing" for low-income countries, where there are few options for HIV/AIDS treatment. HIV-positive people who develop resistance may have few other affordable options, Johnston said, adding, "Finding an effective microbicide is going to be challenging enough. We don't want to compound that with the possibility of creating drug resistance." According to Johnston, trial researchers could use microbicides that contain drug combinations that would not promote the development of resistant HIV strains (Bloomberg/Long Island Newsday, 7/7).
The researchers also found that microbicides, which typically are aimed at protecting women from HIV, could be equally or more effective at protecting men. According to computer models used in the study, if and when microbicides are perfected, they could reduce the risk of men contracting HIV from women. "Paradoxically, although microbicides will be used by women to protect themselves against infection, they could provide greater benefit to men," the authors wrote. Because drug-resistant HIV often is less likely to be transmitted from one person to another, male sex partners of women who have developed resistance related to microbicide use might still be protected from the virus, according to Blower (Reuters, 7/8).
An abstract of the study is available online.
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Drug Access
UNITAID Endorses Creation of Panel To Examine Drug Patent Issues
[Jul 09, 2008]
The drug purchasing agency UNITAID is endorsing the formation of a panel of experts to examine the viability of a "patent pool," the New York Times reports. The pool in theory would hold licenses on patented drugs, and the licenses could be used to produce the medicines at lower costs for developing countries, according to the Times. The pool initially would focus on pediatric HIV/AIDS drugs and medicines for adults who have developed resistance to first-line therapies.
The panel initially would have five experts in patent law and a budget of less than $2 million. "The panel might ask for licenses on second-generation drugs," advocate James Love said, adding, "The patent holders will either say yes or no -- but if they say no, it might raise some eyebrows." Although patents have expired on many first-line HIV/AIDS drugs, patents on many second-line and pediatric medicines still exist. According to the Times, a "tiny fraction" of people taking HIV/AIDS drugs in developing countries have access to newer medicines (McNeil, New York Times, 7/8).
Link to this story.
Global Challenges
Nepal on Track To Meet HIV/AIDS Target, MDGs, Minister Says
[Jul 09, 2008]
Nepal is on track to meet the United Nations Millennium Development Goals by 2015 -- including targets related to HIV/AIDS prevention, treatment and care -- Minister for Health and Population Giriraj Mani Pokharel said recently, Xinhua News Agency reports.
Pokharel was speaking at the Third National AIDS Conference, themed "Towards Universal Access." Pokharel said that the government should ensure no-cost HIV/AIDS treatment and that it is reviewing plans to create a program based on the needs of HIV-positive people in the country. Pokharel also said the cooperation of donors is important to achieving goals in the health sector. "We will not be able to achieve the goals separating our forces into different groups and sectors, hence we should work together to strive for success."
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