News in brief - Nov. 13, 2006

Earlier lung cancer detection - FDA OKs new hepatitis B drug - New fertility guidelines given - Not enough evidence to support surgery for narrowed kidney arteries - Asthma in the obese may be caused by excess weight

Earlier lung cancer detection

A study in the Oct. 26 New England Journal of Medicine found that an annual spiral CT screening can detect lung cancer at a much earlier and more curable stage. The late stage at which lung cancer is often detected has led to a low cure rate.

The success of the study, carried out in 31,567 asymptomatic men and women at risk for lung cancer, should reopen the debate over widespread screening for lung cancer, notes an editorial in the same issue. The new study also found that CT screening for lung cancer was similar in cost-effectiveness to mammography for breast cancer.

FDA OKs new hepatitis B drug

A new molecular entity, telbivudine, or Tyzeka, was approved Oct. 25 by the Food and Drug Administration for the treatment of adults with chronic hepatitis B.

The new drug was studied in a year-long international clinical trial in 1,367 patients with chronic HBV. The results provided evidence of antiviral effectiveness that included suppression of the hepatitis B virus, the FDA reported. Results also showed improvement in liver inflammation comparable with lamivudine, one of five other drugs approved to treat patients with the disease.

In a typical year, an estimated 70,000 Americans become infected with chronic HBV, and about 5,000 will die from related complications, said Steven Galson, MD, MPH, director of the FDA's Center for Drug Evaluation and Research, in a statement.

The most common side effects of the new drug were elevated creatinine phosphokinase, upper respiratory tract infection, fatigue, headache, abdominal pain and cough.

Tyzeka is manufactured by Novartis Pharmaceuticals.

New fertility guidelines given

New guidelines developed by the American Society of Reproductive Medicine and the Society for Assisted Reproductive Technology call for a limited number of embryos to be transferred during in-vitro fertilization procedures. The number should be individualized according to each woman's age and the condition of the embryo, according to the guidelines.

The new document, published in the November Fertility and Sterility, was praised by the March of Dimes for the likelihood that it would result in fewer preterm births and other complications for mother or fetus. More than one-third of pregnancies conceived using assisted reproductive therapies result in a multiple birth.

"New parents may think there's more to love when you have more than one baby, but there's also more to worry about; more than half of twins and nearly all of triplets are born prematurely, associated with increased risk of death and disability," said Nancy Green, MD, March of Dimes medical director.

Not enough evidence to support surgery for narrowed kidney arteries

A growing number of patients are having surgery to treat renal artery stenosis, but available evidence does not show an advantage of this strategy over medication alone, according to a systematic review by the Agency for Healthcare Research and Quality published in the Annals of Internal Medicine online last month and due in print Dec. 19.

Researchers analyzed prospective studies of patients with this condition who underwent either revascularization or medication by itself. The selected studies reported mortality, kidney function, blood pressure, cardiovascular events and other events for at least six months after the end of the project.

Authors could not find strong evidence to support either strategy, although the studies did suggest that there was no significant difference in mortality rates or kidney-related outcomes for either approach. Some evidence did support the possibility that angioplasty could lead to better blood pressure control, but researchers noted that evidence was lacking that could determine who would benefit the most from which intervention.

Asthma in the obese may be caused by excess weight

Symptoms suggestive of asthma among patients who are obese may be a result of the extra poundage rather than inflammation, according to a study published in the September Chest.

Researchers simulated class 1 obesity in eight lean volunteers by having them wear vests weighed down with birdshot. Antigravity suits also were used to increase the pulmonary capillary blood volume. Subjects were then given a methacholine challenge test and had their airway responsiveness assessed. The excess weight caused reductions in expiratory reserve volume, functional residual capacity and total lung capacity.

An association between obesity and asthma has been confirmed by several studies, but it remains unclear how the link operates. Researchers concluded that the decreased lung volume in those who are obese increases airway responsiveness that could be leading to the development of this condition.

"Asthma symptoms seen in people who are overweight may be caused by the obesity-related increased pressure on the chest wall," said Frank J. Cerny, PhD, one of the authors and professor emeritus of pediatrics and exercise and nutrition sciences in the University at Buffalo's School of Public Health and Health Professions.