News in brief - Nov. 21, 2005

AMA comes out against personal antiviral stockpiling - ACIP expands recommendations for hepatitis A vaccination - Painkiller doses and gastrointestinal bleeding - Lengthening pipeline in clinical trials - Trial for new TB treatment - HapMap completed - Several oral rehydration solutions equally effective for sick children

AMA comes out against personal antiviral stockpiling

Patients should not be prescribed antivirals to have on hand in preparation for the possibility that avian influenza might hit here, according to a statement by the American Medical Association this month.

The Association issued the statement in response to anecdotal reports that, in light of the potential threat of a pandemic influenza, patients have been asking for prescriptions for these drugs despite the lack of human cases of the disease here. The concern is that these drugs could be misused or that stockpiling will lead to drug shortages.

"The AMA understands the concern people have for their health and the health of their families with the recent outbreaks of avian flu in birds," said AMA Trustee Ardis D. Hoven, MD. "Needlessly taking an antiviral may contribute to the problem of resistance to that antiviral drug, which would then make the drug less useful in the event of an actual avian flu outbreak."

In the past year, the World Health Organization has recorded 78 cases of human infection with the avian influenza strain.

ACIP expands recommendations for hepatitis A vaccination

All children should be vaccinated against hepatitis A, said an October statement by the Centers for Disease Control and Prevention. The recommendation was by the agency's Advisory Committee on Immunization Practices and is an expansion of the 1999 directive that only children in states with the highest rates of incidence should receive the shot.

In a related action, the Food and Drug Administration last month approved the vaccine to be used in children as young as 12 months. It previously had been approved only for those older than 2 years.

Painkiller doses and gastrointestinal bleeding

People who take high doses of ibuprofen on a regular basis are three times more likely to experience gastrointestinal bleeding than are those who do not take the painkillers, according to a small study published in the November Clinical Gastroenterology and Hepatology.

Significant GI bleeding was observed as early as three days after starting an ibuprofen regimen in otherwise healthy people. "Unfortunately, people dealing with chronic pain, such as arthritis, often increase the recommended dose of their painkillers, and they should be aware that the effects on the GI tract can be serious," said lead author Richard H. Hunt, MD, professor in the Dept. of Medicine at McMaster University Health Science Centre in Ontario, Canada.

Researchers conducted a post-hoc analysis of two separate randomized studies that included 68 healthy volunteers who were given either four weeks of an ibuprofen regimen at 800 mg three times a day for 28 days, or a placebo dosage.

Those taking ibuprofen experienced blood loss ranging from about 40 mL to about 300 mL.

Lengthening pipeline in clinical trials

Longer clinical trial phases are lengthening the time it takes to bring new prescription drugs to market in the United States, according to a recent analysis by the Tufts Center for the Study of Drug Development, in Boston.

The study found that new medicines required an average of 8.5 years to move through the clinical and approval phases in the 2002-04 period.

The number of new drugs approved by the Food and Drug Administration has fallen, and the average clinical times for priority drugs are at their longest since before enactment of the Prescription Drug User Fee Act of 1992, said Kenneth I. Kaitin, PhD, director of the center.

"As drug development becomes more complex and expensive, developers tend to concentrate available resources on fewer projects," he said. "Fewer development projects, in turn, lead to fewer new drug approvals."

Trial for new TB treatment

A clinical trial for the first new treatment against active tuberculosis in decades is about to begin enrolling about 2,500 patients on four continents. The phase 2 trial will study the potential of an existing antibiotic, moxifloxacin, to shorten the standard six-month treatment of TB.

If the trial is successful, Bayer HealthCare AG, which holds the patent on the drug, has pledged to price moxifloxacin affordably for those who need it most in the world's poorest countries.

The trials will evaluate whether the substitution of moxifloxacin for one of the standard TB drugs eliminates TB infection faster than the current standard treatment.

Preclinical studies showed that moxifloxacin cut treatment time by two months when substituted for isoniazid, a cornerstone of TB treatment. Moxifloxacin is already approved in 104 countries to treat certain bacterial respiratory and skin infections.

Multidrug-resistant strains of tubercle bacillus are spreading at a rate of 300,000 newly diagnosed cases each year.

"New options are needed, and they need to be both effective and easier for patients to tolerate," said Richard Chaisson, MD, a professor of medicine, epidemiology and international health at the Johns Hopkins University School of Medicine. Dr. Chaisson will lead two of the studies.

HapMap completed

A catalog of human genetic variation, known as the human haplotype map or HapMap, was recently completed, with initial results published in the Oct. 27 Nature.

The map, which charts the patterns of genetic variation that are common in the world's population, is expected to aid in the search for genes involved in common diseases, such as asthma, diabetes, cancer and heart disease.

The HapMap shows the neighborhoods of correlated genetic variation, or haplotypes, across the entire human genome and consists of more than 1 million markers of variation called single nucleotide polymorphisms, or SNPs.

Any two unrelated people are 99.9% identical at the genetic level. But it is important to understand the 0.1% difference, because it can help explain why one person is more susceptible to disease or responds differently to a drug or an environmental factor than another person, said the international team of researchers who developed the map.

Using HapMap data to compare SNP patterns of people affected by a disease with those of unaffected people, researchers can survey genetic variation across the whole genome and identify genetic contributions to common diseases far more efficiently than is possible with traditional approaches.

Several oral rehydration solutions equally effective for sick children

Children who are dehydrated because of vomiting and diarrhea caused by viral gastroenteritis can be successfully treated with either Gatorade, Pedialyte or a novel solution that includes carbohydrate, sodium and potassium, according to a study presented last month at the Annual Scientific Meeting of the American College of Gastroenterology in Honolulu.

Researchers from the University of Iowa in Iowa City randomized 73 children between ages 5 and 12 at a hospital in India to receive one of the three rehydration solutions and a diet of yogurt and rice. Bowel movements and body weight improved in all subjects. Patients preferred the taste of Gatorade, although this solution was associated with an increased risk of potassium deficiency.

All three groups had a similar rate of hyponatremia, which the authors suggest could mean that some patients need more aggressive measures.

"A small number of patients with dehydration may have significant electrolyte disturbances," said Satish S.C. Rao, MD, PhD, professor in internal medicine at the University of Iowa. "Additional treatment may be necessary."