The two drugs, decitabine and gemcitabine – both FDA approved and currently used in pre-cancer and cancer therapy – were found to eliminate HIV infection in the mouse model by causing the virus to mutate itself to death – an outcome researchers dubbed "lethal mutagenesis."

This is a landmark finding in HIV research because it is the first time this novel approach has been used to attack the deadly virus without causing toxic side effects. Because decitabine and gemcitabine are already FDA approved, researchers believe that if their research is effective in large animal models, it will be much easier to expedite the development of the drugs for human use.

The study is a collaboration between molecular virologists Louis Mansky, Ph.D., and Christine Clouser, Ph.D., of the Institute for Molecular Virology and School of Dentistry, as well as medicinal chemist Steven Patterson, Ph.D., from the Center for Drug Design. The findings were recently published online in the Journal of Virology.

"The findings provide hope that such an approach will someday help the 33 million people worldwide who currently live with HIV," Mansky said.

Lethal mutagenesis
HIV mutates and evolves quickly. Rather than inhibiting virus growth and replication like current HIV drugs, this new drug combination forces the virus to do just the opposite – evolve beyond control, to the point of extinction.
"HIV's ability to mutate makes it difficult to target and treat," Mansky said. "We wanted to take advantage of this behavior by stimulating HIV's mutation rate, essentially using the virus as a weapon against itself."

Drug repositioning
One way to decrease cost and expedite the development of novel drugs is by the use of drug repositioning, the process of taking a drug that is used to treat one medical condition, and using it to treat a different illness.

By examining drugs that are already approved by the Food and Drug Administration, the researchers hope to expedite the development of this drug combination because the safety profiles of the two drugs are known.

U of M researchers found that the drug concentrations needed to eliminate HIV infection cause no measureable cell toxicity and were effective against HIV cultures at concentrations well below the current levels used for cancer treatment.

The path ahead
Gemcitabine and decitabine have been administered in pre-clinical trials with mice. Initial findings confirm that the drugs are an effective antiviral therapy for HIV.

The researchers are now in the process of modifying the drugs to forms that can be absorbed by the human body when taken orally.

The trial, which randomized 400 gay men to take either a daily tenofovir (Viread) or a daily placebo pill, was too small to serve as an efficacy trial.
Lisa Grohskopf of the US Centers for Disease Control (CDC) told the conference that none of the seven men who became infected with HIV during the trial was taking tenofovir but, because of the size of the trial, this could possibly be a random effect - nothing could be read into it about the efficacy of once-daily tenofovir as a means of preventing HIV.

This is a similar situation to the only other previous PrEP trial, from Ghana, which a reported a non-significant reduction in HIV infections in women taking PrEP (see aidsmap report: First hint that PrEP might work in humans).

Inevitably, though, it will be taken as a promising signal in advance of the next trials to report - the CDC 4370 trial in Thai drug users (see aidsmap report: Early data from the Thai trial ) and the predominantly South American  iPrEX trial in gay men (see more on community consultation on aidsmap), which are due to report at the beginning of next year.

This trial, however, was intended as a safety trial, looking closely at side-effects of the tenofovir medication and especially at risks already associated or suspected of association with tenofovir, such as kidney failure and bone mineral loss.

The trial recruited gay men from San Francisco, Atlanta and Boston, and randomized them into four groups of 100. Two groups took either tenofovir or a dummy pill from the start, for two years. The other two waited for nine months before starting either tenofovir or placebo, and took them for the remaining 15 months. This was in order to have data from a control group that took no daily pills at all, in order to find out if taking a daily pill changed sexual and risk-taking behavior.
In the end, 373 men started taking tenofovir or placebo and 323 completed the study, a retention rate of 86%.

The average age of the participants was 38.5 and there was a nearly significant difference in the racial balance of the trial, with 18% of those on placebo being African-American and 12% of those on tenofovir (p=0.07).

Participants had had, on average, four male partners in the last three months; 29% of those on tenofovir and 33% on placebo had had unprotected sex in the last three months (not a significant difference); and 12.5% of the participants had had risky sex, i.e. unprotected sex with someone who was or could have been HIV-positive.

There was virtually no difference in the rate of adverse events seen between patients on tenofovir and those on placebo. The only side-effect in which a significant difference was seen was back pain, suffered by 13% on tenofovir and 6% on placebo (p=0.04), and there were no differences in the rate of any serious side-effect.

In particular, there was no elevation whatsoever in creatinine levels (an indicator of kidney problems) and the rate of low blood phosphate, an indicator of possible bone mineral loss, was if anything higher in participants taking placebo, although not significantly so (p=0.12).

One person died during the trial, of an accidental overdose of opiate drugs with alcohol.

Seven participants tested HIV-positive during the trial. One of these was clearly someone recruited in the window period for HIV infection; he was HIV-negative when screened, but HIV-positive on the first day of enrolment, with a viral load of 1770 copies/ml.

Of the other six, three were on placebo when they contracted HIV and the other three were in one of the delayed-treatment arms and had not started taking either tenofovir or placebo. No tenofovir resistance was seen.

Sexual risk behavior did not change significantly during the trial. At baseline, the proportion of men who said they had had unprotected anal sex during the last year was 60% in the immediate-treatment arm and 53% in the delayed-treatment arm (note that this was over a longer period than the baseline questionnaire, which asked about sexual behavior in the last three months).

It went down from the beginning of the trial to the next quarterly visit, an effect often seen in trials, and went down more steeply in those immediately randomized to tenofovir, to 46% - suggesting that taking a daily pill may serve as a reminder to use condoms rather than a disincentive. It rose very slightly and non-significantly thereafter to about 55% in the immediate-treatment arm, but did not rise at all in the delayed-treatment arm.

Further analyses are continuing, which will look into risk behavior more deeply, though as a member of the audience commented, it's much less likely that people would take more sexual risks if they knew they might be taking an inactive placebo than if they were sure they were on tenofovir. Analyses will also look directly at bone mineral density and assess adherence.

Reference

Grohskopf L et al. Preliminary analysis of biomedical data from the phase II clinical safety trial of tenofovir disoproxil fumarate (TDF) for HIV-1 pre-exposure prophylaxis (PrEP) among U.S. men who have sex with men (MSM). Eighteenth International AIDS Conference, Vienna, abstract FRLBC102, 2010.

In one study involving nearly 900 men and women in Baltimore and Los Angeles, the researchers found that those who used lubricants were three times more likely to have rectal sexually transmitted infections (STIs). Another study that subjected popular over-the- counter and mail-order lubricants to rigorous laboratory tests discovered that many of the products were toxic to cells and rectal tissue. If in humans, theses products have the same effect, the cells might be rendered more vulnerable targets for HIV infection than they already are.

In the United States alone, receptive anal intercourse is practiced in up to 90 percent of gay and other men who have sex with men, according to international Rectal Microbicides Advocates. Moreover, the practice is not limited to men. U.S. estimates and surveys in the United Kingdom indicate 10 to 35 percent of heterosexual women have engaged in anal sex at least once. Globally, estimates suggest 5 to 10 percent of sexually active women are having anal sex. While condoms are generally effective for protecting against HIV and other STIs, most acts of anal sex go unprotected.

Microbicides - substances applied topically on the inside of the rectum or vagina - could potentially help prevent the rectal transmission of HIV, and some are being tested in early Phase I studies. Another approach called oral pre-exposure prophylaxis (PrEP) involves the use of antiretroviral drugs to reduce the risk of HIV in HIV negative people. A large Phase III trial of PrEP involving men who have sex with men in South Africa and the United States is expected to report results by early next year. Yet if either of these approaches is found effective in clinical trials, they will do no good if those most at risk don't use them. Other research presented at the conference sheds light on this issue. Summaries of all three studies are provided below.

Use of lubricants with anal sex associated with more rectal ETIs
Lubricants are typically used before and during receptive anal intercourse, but their use could increase the risk of rectal sexually transmitted infections (STIs) a study involving nearly 900 men and women in Baltimore and Los Angeles has found. Even after controlling for gender, HIV status, city, condom use, and number of sex partners in the past month, the association between lubricant use before receptive rectal intercourse and rectal STIs remained strong, reported Pamina Gorbach, Dr.PH. from the School of Public Health and the David Geggeffen School of Medicine at the University of California, Los Angeles, who led the study. According to the study's statistical analysis that considered the HIV status, gender, condom use and study site, participants who use lubricants before receptive anal intercourse were three times more likely to have a rectal STI. Although the analysis didn't consider the specific lubricants being used, it may be that certain types of products are more irritating to the lining of the rectum than others, which could increase men and women's vulnerability to rectal STI's, the researchers suggest.

The study, which was conducted between October 2006 and December 2008, examined the rectal health and behaviors of 879 men and women. Participant in the study were tested for gonorrhea and Chlamydia and asked about their sexual and hygiene practices in private computer-base interviews. Of the 879 participants, 421 reported having receptive anal intercourse in the past month a (229 men) or in the past year (192 women) and of these 421, 302 provided the researchers with additional information about their use of lubricants. About half, or 147 (523.7 percent) said they used a lubricant when they last engaged in anal sex.

Of the 302 included in the analysis, 25 (8.3 percent) tested positive for a bacterial rectal STI (5.6 percent of women and 10.2 percent of men). But among those who said they recently used a lubricant, the number of STIs was higher. With STI test results available for 145 of the 147 recent users, the researchers found that 17 (11.7) tested positive for a rectal STI compared to just seven (5.1 percent) of the 156 who said they did not use a lubricant. A higher percentage of African Americans (61 percent) reported using lubricants than did Hispanics (40.4 percent) and whites (23.2 percent) A higher percentage of HIV-positive participants (56 percent) were more likely to report using lubricants than were HIV negative participants (43.7 percent). Most of the participants who reported using lubricants said they used a water-based lubricant (78 percent); 28 percent used silicon-based products, 17 percent oil based lubricants and 6 percent said they had used numbing lubricants. More research will be needed to understand exactly how lubricants facilitate transmission of STIs, including HIV, the researchers say.

Study is first to evaluate safety of lubricants used in anal sex
A laboratory study that compared over-the-counter and mail order lubricants commonly used with receptive anal intercourse found many of the products contain higher amounts of dissolved salts and sugars compared to what's normally found in a cell. As a result, the products had toxic effects on the cells and rectal tissue studied. Some of the lubricants caused significant portions of the epithelium - the layer of cells that serves as a protective barrier inside the rectum - to be stripped away. Conclusions cannot be made based on this study alone, though the results are compelling enough to wonder if these lubricants might have the dame effect in people and thereby increase susceptibility to HIV, commented Charlene Dezzutti, Ph.D., from the University of Pittsburgh and Magee-Women Research Institute, who led the study for the Microbicide Trials Network. The study, which was conducted in collaboration with International Rectal Microbicides Advocates (IRMA), was undertaken because little is known about the safety of lubricants even though they are frequently used during anal sex.

Six products were studied. Five (Astroglide, Elbow Grease, ID Glide, KY Jelly and Wet Platinum) were selected because they had been identified as those most commonly used by the more than 6,300 respondents to an IRMA survey. The sixth product (PRE) was selected to serve as a control because it is isosmolar. Osmorality refers to the concentration of dissolved particles (salts and sugars) found inside a cell relative to the outside. A product that is somolar has the same concentration of particles as inside the cell, whereas a product that is hyperosmolar has a higher concentration of salts and sugars relative to the cell. To correct this imbalance, a cell forces water out but then it becomes withered and dies. Most of the lubricants studied were water-based, except for Wet Platinum, which is a condom-compatible silicone-based product. The researchers characterized each product according to its osmolarity, pH and viscosity - or slipperiness. Studies then were conducted to determine the effect of each lubricant on different cell types, rectal and cervical tissue and on bacteria (microorganisms that are important to the health of the rectum). Based on the tests performed, PRE and Wet Platinum were shown to be safest, while Astroglide was the most toxic to cells and tissues, and KY Jelly had the worst effect on the good bacteria, essentially wiping out and entire colony. PRE was the only water-based lubricant that was not hyperosmolar and did not disrupt the epithelium. None of the lubricants had measurable anti-HIV activity. In future studies, the researchers hope to determine the effect that different lubricants have on susceptibility to HIV infection in tissues.

The bad news: Boston survey finds awareness about PrEP poor among MSM; The good news: MSM likely to use PrEP and Microbicides for prevention
Despite being representative of one of the highest at-risk populations for HIV, a large number of HIV-uninfected men who have sex with men (MSM) surveyed as part of a study had never heard of pre-exposure prophylaxis (PrEP), the use of antiretroviral (ARV) drugs by HIV-negative individuals for preventing HIV. PrEP is being evaluated in several trials in different at-risk population, including MSM. The study, which was conducted in the Boston area, involved 105 MSM who reported having unprotected receptive anal intercourse at least once in the prior year with a partner they knew was HIV positive or didn't know for sure whether or not they were infected. The participants had been enrolled in a study to determine the acceptability of rectally administered placebo gels and suppositories. The survey was conducted at the time of enrollment to help understand the demographic and behavioral factors that may increase men's likelihood for using a microbicide or oral PrEP, reported Kenneth Mayer, M.D. of the Fenway Institute in Boston and Brown University in Providence R.I. The average participant's age was 39; 70.5 percent had at least a high school education; 24 percent were African-American and 8.6 percent were Latino. Participants reported having an average of more than four sex partners in the two months prior to their enrolling in the study.

While 44.8 percent of the participants had heard of post exposure prohylaxis (PEP) for preventing HIV, whereby anti-HIV drugs are administered within 72 hours of an exposure, such as through unprotected sex or an occupational needle-stick injury, only 20 percent had heard of PrEP. However, once participants were informed about both approaches, as well as about rectal microbicide, nearly 60 percent indicated they would likely use PEP, 40 percent said they would use PrEP, and half said they would likely use a rectal gel for prevention. The responses did not differ by demographic characteristics. Men who indicated they were most likely to use rectal microbicide were also more likely to use PrEP. While the study was small, the results are instructive to efforts for raising awareness and understanding about the HIV prevention approaches that are currently in clinical trials. This in turn may help facilitate adherence to and improve effectiveness of these approaches if they become widely introduce, say the researchers.

However, they found that during the first year of HIV treatment, viral load was above the threshold of 1,000 copies/ml associated with onward transmission for approximately 5% of the time.

"In this nationwide population-based cohort (group of people with same characteristics) study of Danish HIV-infected patients on HAART (highly active antiretroviral therapy) with more than six months of suppressed viral load, we found that the risk of experiencing a viral load above 1000 copies/ml and thereby transmitting HIV sexually was very low", comment the investigators.

There is intense debate about the risk of people with HIV taking antiretroviral therapy and who have an undetectable viral load transmitting HIV to their sex partners if they do not use condoms.

This debate was kick-started by a statement from the Swiss Federal Commission for HIV/AIDS that stated "a seropositive person without additional sexually transmitted disease on antiretroviral treatment with suppressed viral load cannot transmit sexually".

In order to be considered uninfectious, the Swiss said that an individual must fulfill three conditions:

• Be taking a stable antiretroviral regimen with a viral load below 50 copies/ml for at least six months.
• Have good adherence to treatment.
• Be free of any untreated sexually transmitted infections.

The Swiss also noted that their recommendations were based on data obtained from heterosexual couples in reportedly monogamous relationships.

Although no country has changed its official guidance advising condom use to prevent HIV transmission, there is some evidence that HIV-positive individuals and their partners have accepted the Swiss recommendations.

Danish HIV physicians wished to assess the likelihood of viral load increasing to levels associated with onward transmission in patients taking suppressive HIV treatment.

They therefore analyzed the viral load results of 2,680 patients obtained between 2000 and 2007. The investigators defined a plasma viral load above 1000 copies/ml as being potentially infectious, and a viral load below this level as being uninfectious. This threshold was based in part on research in heterosexual couples not receiving treatment in the Rakai district of Uganda. That study showed that no infections occurred when the HIV-positive partner had a viral load below 1,500 copies/ml.

Just over a third (38%) of patients reported being in a relationship, and 78% said that they always had safer sex.

Viral load tests were performed on average every three months. The patients contributed 9,348 person-years of follow-up and the investigators calculated that for 0.6% of this time, patients had potentially infectious levels for a little over 1% of the time.

Thereafter, viral load was above the potentially infectious threshold for an average of 0.6% of the follow-up period.

However, amongst patients who had been taking suppressive HIV treatment for over five years, only 0.03% of follow-up was spent with a viral load above 1000 copies.

Analysis by subgroup did not greatly affect these results. But the researchers did notice that injecting drug users taking suppressive HIV treatment had a potentially infectious level of viral load 1.5% of the time. This was attributed to poorer treatment adherence in this population.

"Assuming that there is a viral threshold of infectiousness, our results indicate that the risk of viraemia is very low in patients on successful antiretroviral treatment", write the investigators.

Noting that "HIV-infected patients have, however, an increased risk of abrupt viraemia in not just the first six months but the first twelve months of episodes with undetectable viral load", the investigators recommended by the Swiss.was extended from six months to at least twelve months."

An important limitation of this study is the inability of the investigators to assess the extent to which plasma viral load differed from viral load in genital fluids, and the extent to which any divergence might be influenced either by time on therapy, drug regimen or sexually transmitted infections.

Some sexually transmitted infections have been associated with an increased likelihood of detectable virus in genital fluids even when plasma viral load is undetectable; leading some experts to argue that in populations with high rates of sexually transmitted infections, undetectable viral load may be unreliable markers for assessing and individual's risk of transmitting HIV.

Reference
Engsig FN et al. Risk of high-level viraemia in HIV-infected patients on successful antiretroviral treatment for more than 6 months. HIV Med, online edition, DOI:10.1111/j.1468-1293.2009.00813.x.2010

A surprising number of older men did not consider penile-vaginal intercourse to be sex. More than idle gossip, the answers to questions about sex can inform - or misinform - research, medical advice and health education efforts.

"Researchers, doctors, parents, sex educators should all be very careful and not assume that their own definition of sex is shared by the person they're talking to be it a patient, a student, a child or study participant," said Brandon Hill, research associate at the Kinsey Institute.

The study, conducted in conjunction with the Rural Center of AIDS/STD Prevention in IU's School of Health, Physical Education and Recreation, delves deeper into a question first examined in 1999 - in the midst of a presidential sex scandal where the definition of sex was an issue. Researchers from The Kinsey Institute asked college students what "had sex" meant to them, taking the approach, which was unique then, of polling the students on specific behaviors.

No consensus was found then, either. The new study, published in the international health journal Sexual Health in February, examined whether more information helped clarify matters - study participants were asked about specific sexual behaviors and such qualifiers as whether orgasm was reached - and researchers also wanted to involve a more representative audience, not just college students.

"Throwing the net wider, with a more representative sample, only made it more confusing and complicated". Hill said. "People were even less consistent across the board."

The study involved responses from 486 Indiana residents who took part in a telephone survey conducted by the Center for Survey Research at IU.

Participants, mostly heterosexual, were asked, "Would you say you 'had sex' with someone if the most intimate behavior you engaged in was., "followed by 14 behaviorally specific items. Here are some of the results:

- Responses did not differ significantly overall for men and women. The study involved 204 men and 282 women.
- 95 percent of respondents would consider penile-vaginal intercourse (PVI) having had sex, but this rate drops to 89 percent if there is no ejaculation.
- 71 percent and 73 percent considered oral contact with a partner's genitals (OG), either performing or receiving, as having had sex.
- Men in the youngest and oldest age groups were less likely to answer "yes" compared with the middle two age groups for when they performed OG.
- Significantly fewer men in the oldest age group answered "yes" for PVI (77 percent).
- Hill said it is common for a doctor, when seeing a patient with symptoms of sexually transmitted infections, to ask how many sexual partners the patient has or has had. The number will differ according to the patients' definition of sex.

Hill said it is common for a doctor, when seeing a patient with symptoms of sexually transmitted infections, to ask how many sexual partners the patient has or has had. The number will differ according to the patients' definitions of sex.

"There's a vagueness of what sex is in our culture and media," Yarber said. "If people don't consider certain behaviours sex, they might not think sexual health messages about risk pertain to them. The AIDS epidemic has forced us to be much more specific about behaviours, as far as identifying specific behaviours that put people at risk instead of just sex in general. But there's still room for improvement."

Reference
Sanders S et al. Misclassification bias: diversity in conceptualizations about having 'had sex'. Sexual Health 7 (1): 31-34, 2010

Inflammation, other immune-system factors may increase cardiovascular risk, A Massachusetts General Hospital has found that relatively young men with longstanding HIV infection and minimal cardiac risk factor had significantly more coronary atherosclerotic plaques-some involving serious arterial blockage-than did uninfected men with similar cardiovascular risk. The investigation appearing in the January 2010 issue of the journal AIDS is the first to use CT angiography to identify coronary artery plaques in HIV-infected participants.

“We were particularly surprised to find that several of the HIV patients-none of whom had symptoms of heart disease-had obstructive coronary artery disease, which was found in none of the controls,” says Janet Lo, MD, of the Program in Nutritional Metabolism in the MGH Department of Medicine, who led the study. “It appears that both traditional and nontraditional risk factors are contributing to atherosclerotic disease in HIV-infected patients.”

Several previous studies have found increased incidence of heart attacks and other cardiovascular events among HIV-infected patients, but it has not been clear whether that risk was attributable to recognized risk factors, such as elevated cholesterol and smoking, or to HIV-related immune system factors. The current study enrolled 110 men- 78 with HIV infection and 32 uninfected controls-without symptoms of cardiovascular disease. Participants ranged in age from 18 to 55, and both groups had low levels of traditional cardiovascular risk factors. The HIV positive participants had longstanding infection, were generally healthy, and the great majority were receiving antiretroviral therapy.

After a detailed interview and physician examination, participants received both a standard cardiac CT scan using a 64-slide multidetector CT scanner and CT angiography. While the cardiac CT scan identifies calcium deposits in coronary arteries, CT angiography can also find non-calcified arterial plaques. The standard scans showed that the HIV-infected participants had levels of coronary calcium that, based on previous studies, would be expected in men who were six years older. The CT angiography revealed coronary atherosclerosis in 59 percent of the HIV-infected patients, compared with only 34 percent of controls. Five of the HIV-positive participants had critical coronary stenosis-70 percent or greater narrowing of one or more arterial segments something seen in none of the controls. Those participants were all referred to cardiologist for further evaluation and treatment.

“Our finding highlights the need to address reduction of cardiac risk factors early in the course of HIV disease and for caregivers to consider that even asymptomatic patients with longstanding HIV disease and minimal cardiac risk factors may have significant coronary artery disease” says Lo, who is an instructor in Medicine at Harvard Medical School. “We also found interesting associations between the degree of atherosclerosis and how long participants had been infected with HIV and with several inflammatory and immune factors. Future studies are needed to clarify the role of these nontraditional risk factors and find the best prevention and treatment strategies for these patients”

In a laboratory study, the researchers evaluated the effect of methamphetamine on HIV-1 replication in vitro. They then performed a study in transgenic (genetically modified) mice carrying replication-competent HIV provirus (integrated genetic material) and the human protein cyclin T1, which plays a role in HIV transcription (copying of viral genetic material).

Results
• Methamphetamine administration significantly increased HIV production by both HIV-infected monocytes and CD4 T-cells in vitro.
• In mice, methamphetamine treatment increased HIV production and viral load.
• Methamphetamine exposure activated transcription of the HIV long terminal repeat (LTR) regulatory region, thereby facilitating viral replication.
• Methamphetamine exposure was also associated with nuclear translocation of nuclear factor kappa B (NF-B), a protein that plays a role in regulating immune response.

"Our results provide further insights into the mechanisms by which methamphetamine accelerates disease course in HIV-infected individuals," the study authors concluded.

Department of Pediatrics, Department of Microbiology and Immunology, and Department of Pathology, Albert Eistein College of Medicine, Bronx NY.

Reference
SS Toussi, A Joseph, JH Zheng, and others. Methamphetamine Treatment