Pharmacy Perspectives - Fall 2012 - (Page 17)

ReseARCH Anderson’s Lab Instrumental in Proving HIV Prevention Drug 91% Effective T Who can take Truvada? Truvada is approved for healthy, uninfected people who are at high risk of contracting HIV through sex. These include sex workers and people with partners who are HIV-positive or engage in high-risk behaviors, such as using IV drugs. hanks in part to work performed at Dr. Peter Anderson’s lab at the Skaggs School of Pharmacy and Pharmaceutical Sciences, doctors now have another weapon against HIV/AIDS in their arsenal, and it’s a potent one. For the first time since the virus was discovered thirty years ago, the U.S. Food and Drug Administration (FDA) approved a drug treatment that will prevent infection in healthy people. The drug, called Truvada, which is already approved for the treatment of HIV in infected patients, works by lowering the amount of virus circulating in people’s blood. But clinical trials show that it can also protect uninfected high-risk people from acquiring the virus, if they take the drug daily before and after exposure. Dr. Anderson’s lab helped zero in on Truvada’s effectiveness. Tasked with analyzing the blood samples of study participants, Anderson’s initial analysis showed that the drug protected about 44 percent of the people taking it. “That’s pretty remarkable, but maybe not truly compelling,” says Anderson. “So we looked a little closer.” And what they found was revealing. “We did the run and the lab manager called me in, he said, you might want to come in here and look at the pictures of where the drug levels are supposed to be on the screen, because there’s none there,” says Anderson. That suggested that some of the people in the study who said they were taking the drug every day, actually weren’t. So, Anderson contacted the study’s lead authors to find out if the samples which showed no detectable amounts of the drug matched up with the people who contracted HIV. “That was the a-ha moment. You put the information together and voila – the answer was that the people who contracted HIV just didn’t have enough drug in their blood.” Based on Anderson’s work, researchers recalculated their numbers and discovered that Truvada may be closer to 90 percent effective at preventing HIV infections. That finding is at least part of the reason an FDA advisory committee recommended that the agency approve Truvada as effective protection against HIV. “It’s a very big deal because, of course, we’ve been searching for a vaccine ever since we discovered this was a virus, and that seems to be far off yet, and so this is the first medical therapy tool we’ve got, so I think it is a big breakthrough,” says Anderson. Finding drugs like Truvada in a blood sample isn’t easy. You can’t see it with a microscope. Typical blood tests look at plasma, the liquid that surrounds blood cells. Finding out what’s inside the blood cells themselves is much tougher. The process begins with a centrifuge, which takes the blood sample and continually reduces it, removing everything but the drug they are looking for. “We spin ‘em down so you get that pellet of cells at the bottom of the tube, then we lyse that pellet with methanol and then use progressively stronger concentrations of salt water to purify the drug,” explains Anderson. What’s left at the end is a clear liquid, about the size of a teardrop. Then, the liquid is placed in a mass spectrometer, which uses electric and magnetic fields to identify the molecular mass of a sample’s ions. This in turn tells researchers if the particular substance they’re looking for is present. Thrilled to have a hand in a potential HIV prevention breakthrough, Anderson recognizes that the approval of this latest weapon in the fight against AIDS is controversial. Some public health experts argue that allowing the drug to be used for prevention will foster a false sense of security among users, leading people to believe mistakenly that they are immune to the virus and reduce their use of condoms. However, the FDA determined that the benefits of expanding the pool of people who may use Truvada to protect against HIV made it worth approving. Does Truvada cure AIDS? No. The drug can treat people who are infected with HIV by lowering the amount of virus in their bodies and slowing down the progression of the disease. In healthy, uninfected people, the drug can block the activity of an enzyme that the virus needs to reproduce, thereby preventing HIV’s ability to take hold in healthy cells and start an infection. Why is the approval controversial? Some experts believe that healthy people may not take the drug correctly — it needs to be taken daily to be effective — which would encourage HIV to become resistant to the medication. Public health officials also worry that people may engage in more risky behaviors when they are on the drug, believing they are protected completely against HIV, which they are not. However, patients who receive Truvada prophylactically will be expected to participate in a comprehensive HIV protection plan involving regular HIV testing, condom use and prevention counseling and support. Clinical trials have not shown that users are more likely to engage in risky sexual behavior. scientific discovery Fall 2012 17

Table of Contents for the Digital Edition of Pharmacy Perspectives - Fall 2012

Pharmacy Perspectives - Fall 2012
Contents
Dean’s Message
Centennial Scholars
Commencement
Faculty
Tributes

Pharmacy Perspectives - Fall 2012