Sildenafil citrate (VIAGRA)

Merck and Co’s failed AIDS vaccine may not have worked, but it probably did not raise the risk of infection either, doctors said Tuesday.

Data analyzed after the large clinical trial was stopped in 2007 contradict earlier findings that suggested some groups, such as uncircumcised men, may have been more vulnerable to infection if they got the vaccine, Dr. Susan Buchbinder of the San Francisco Department of Public Health told an AIDS vaccine conference.

Merck’s STEP trial involved 3,000 people in South America, the United States, Canada and Australia. Researchers were not only dismayed that it appeared to do no good, but may have harmed some of the volunteers.

“With ongoing follow-up, the trend in the wrong direction is diminishing,” Buchbinder said in an interview. “Either they were at risk, and that has gone away, or they were never at increased risk. It was never significant.”

Researchers working to produce AIDS vaccines are in Paris this week to pore over the results of the latest experiments.

Of particular interest is a trial in Thailand that has just shown it may be possible to make a vaccine to prevent AIDS; the first hint of success in the 25 years since the pandemic began.

Buchbinder said researchers who worked on the Merck vaccine continue to monitor participants from the trial and are drawing insights from it even now. Lessons learned will be crucial in the making of AIDS vaccines.

STILL LEARNING

Twenty-nine people in the STEP trial who were infected showed a slight decrease in their viral load — a measure of virus in the blood — for a short time, she said.

“The bigger picture issue is that we see some clues here and some clues there about ways where the vaccine may be providing some protection. Overall it didn’t protect, but can we learn something about places where the vaccine may have provided even small amounts of protection so that we can build on those,” she said.

The vaccine aimed to fight AIDS by encouraging so-called cell-mediated immunity, jump-starting T-cells to tackle the virus and stop or slow the progress of the human immunodeficiency virus. It used a weakened virus called adenovirus-5 as a “vector” to transport the vaccine into the body.

Buchbinder said the STEP study also showed the importance of studying the effects of such vectors on the immune system.

“We never understood the complexity of the immune response against the vector and we think that is a very important thing to understand. Animal studies can’t address that because adenovirus 5 does not normally infect non-human primates,” she said.

“These efficacy trials are really moving science forward,” Buchbinder added.

“With each step we are learning more information that we couldn’t get any other way …. We don’t know what it is going to take to make a safe and effective vaccine. Each of these studies, particularly larger trials in humans, help shine a light on issues that we didn’t know or understand before.”

Hooked on cocaine or cigarettes? The U.S. government wants drug companies to make a vaccine for that.

Convinced of the need for new and better treatments for addiction, the government is focusing its efforts on vaccine development as a new way to treat and possibly prevent addiction to a range of addictive substances.

“It’s a perspective that is very different from what we’ve operated on in the past,” Dr. Nora Volkow, director of the National Institute on Drug Abuse told reporters this week at the Society for Neuroscience meeting in Chicago.

Volkow said the agency intends to piggyback on the frenetic investment by drug companies in vaccine development, spurred by the need for new products and the runaway success of products like Merck’s Gardasil vaccine to prevent the virus that causes cervical cancer.

“There is an enormous amount of research and development in vaccines for cancers and a wide variety of disorders,” she said. “We can take advantage of those developments.”

But first Volkow has to tempt drug companies to develop the vaccines by funding costly clinical trials.

Earlier this month, her agency, part of the National Institutes of Health, awarded Nabi Biopharmaceuticals a $10 million grant — the agency’s largest ever — for a late-stage clinical trial of Nabi’s vaccine for nicotine addiction called NicVAX.

Volkow said she did her homework before backing the Nabi vaccine to ensure it was significantly different from other products. “Nonetheless, when you are investing in something at this level, it can be very risky,” she said.

The vaccine is meant to stimulate the immune system to make antibodies against nicotine, blocking its rewarding effects and helping to prevent relapse in smokers trying to quit.

TOUGH MARKET

A similar anti-smoking vaccine by Cytos Biotechnology and Swiss drugmaker Novartis last week missed its main goal in a midstage study, leading some analysts to question whether it can make it to market.

“They are still looking at it but it has been very problematic,” said Robert Wasserman, director of investment research at the investment banking firm Dawson James in Florida.

“Vaccines are really tough,” he said. “It’s not for the faint of heart.”

Still, if it works, a nicotine vaccine could have a huge impact, Volkow said. “It’s an international problem that kills 5 million individuals every year across the world,” she said.

The global market for smoking cessation is expected to reach $4.6 billion by 2016, and vaccines could account for $2 billion in sales, according to independent market research firm Datamonitor.

Volkow said the same methods for making a nicotine vaccine could be used for other illicit substances.

Her agency backed a study released this month of an anti-cocaine vaccine that helped block the high felt by 38 percent of addicts who took it.

The vaccine was developed by Dr. Thomas Kosten of Baylor College of Medicine in Houston, who used a similar approach to make a nicotine vaccine now being tested in Europe by private equity firm Celtic Pharma.

Volkow said drumming up drug company interest in vaccines for illicit drugs is a harder sell because of liability concerns, and the fact that drug abusers are stigmatized.

“Unfortunately, when it comes to treatments for drug addiction … most of the investment goes to the government,” she said.

Newborn babies shouldn’t be expected to sleep through the night. Their bodies are so tiny that they should be awakened if they haven’t eaten for at least five hours, the Nemours Foundation says.

But there are things that new parents can do to help ensure a safe night’s rest for their little one. The foundation offers these suggestions:
Put baby to sleep on his or her back to reduce the risk of sudden infant death syndrome (SIDS).
Don’t let baby sleep with plush bedding, blankets or pillows.
Remove stuffed animals from baby’s crib when it’s bedtime.
Each night, alternate which side of his or her head your baby sleeps on, to prevent development of a “flat spot” on a favored side of the head.

As if migraine sufferers didn’t already have enough pain, new research has found that they may also be more prone to hangover headaches.

U.S. researchers studied the effects of alcohol on a group of rats that experience recurrent migraines as well as a group of control rats that don’t get the headaches. The study authors found that the rats with migraines experienced more pain four to six hours after ingesting alcohol than the control rats.

“Our results suggest that dehydration or impurities in alcohol are not responsible for hangover headache,” Michael Oshinsky, an assistant professor of neurology at Jefferson Medical College of Thomas Jefferson University, and a member of the Jefferson Headache Center team, said in a university news release.

“Since these rats were sufficiently hydrated and the alcohol they received contained no impurities, the alcohol itself or a metabolite must be causing the hangover-like headache. These data confirm the clinical observation that people with migraine are more susceptible to alcohol-induced headaches,” Oshinsky added.