SAN FRANCISCO – Two combination treatments for gonorrhea were almost 100 percent effective, U.S. researchers said, and may help stave off strains of the sexually transmitted disease that have become resistant to available antibiotics.
The study of 401 people used combinations of the pill azithromycin with either the injectable drug gentamicin or another pill gemifloxacin, according to data presented Monday at the International Society for Sexually Transmitted Diseases Research meeting in Vienna, Austria.
Treatment options for gonorrhea, the second-most common disease in the U.S. that doctors must report to health authorities, have been limited as medicines starting with penicillin lose effectiveness. In Britain, doctors began using one of the new combinations and reported in the Lancet in June that resistance to cefixime, a first-line pill, had dropped for the first time in four years. About 800,000 new infections occur every year in the United States, said Gail Bolan of the Centers for Disease Control and Prevention.
“This is an encouraging development, but we’re still working in a very discouraging field,” Bolan said in a telephone interview. “This is not the solution we’re looking for. It’s a good fall-back.”
The study enrolled men and women in six U.S. cities ages 15 to 60 who hadn’t been treated for their gonorrhea infection. Of the group, about half received gentamicin and azithromycin and about half took gemifloxicin and azithromycin. One-quarter to one-third of the patients experienced nausea. Some patients also suffered from diarrhea.
While the study results offer treatment options, the severe side effects are a reason CDC officials are not recommending a change in current guidelines, said Bolan, director of the CDC’s sexually transmitted disease prevention program. The recommended first-line therapy for gonorrhea remains injectable ceftriaxone, a decision made in August after patients demonstrated resistance to the last-available first-line pill.
Gonorrhea is caused by bacteria transmitted during sexual contact and can result in a burning sensation when urinating in men and women. Left untreated it can cause complications including infertility and a life-threatening infection of the blood and joints.
The regimens reported in Monday’s study were developed by taking existing drugs that are known to work on bacteria similar to gonorrhea, known as gram-negative bacteria. The researchers also looked to bioterrorism stockpiles for anthrax treatments, Bolan said. The drugs were already approved by the Food and Drug Administration.
“We’re being creative,” Bolan said. “We’re discouraged we’re not further along with better options.”
Large pharmaceutical companies don’t make enough money on antibiotics to support developing this kind of treatment, Bolan said. A proposal called Generating Antibiotic Incentives Now that created incentives for drug companies and researchers to develop antibiotics was included in the FDA reauthorization legislation passed last year by Congress.
“As an infectious disease doctor, it’s hard to believe in my career, I’ve gone to having diseases I can’t treat,” Bolan said. “We’ve got some challenges ahead.”