Two new promising treatments for gonorrhoea may help fight the growth of drug-resistant strains of the sexually transmitted bacteria, according to a new US government study.
The two antibiotic regimens use existing drugs in new combinations , injectable gentamicin with azithromycin pills, or gemifloxacin pills with azithromycin pills.
Gonorrhoea is one of the most common sexually transmitted diseases in the United States, with more than 800 000 new infections estimated to occur each year, according to the US Centers for Disease Control and Prevention. Untreated, it can lead to problems with the prostate and testicles for men, and infertility in women. This is why its increasing antibiotic-resistance is a serious concern.
The US government study included more than 400 men and women, aged 15 to 60, with untreated gonorrhoea infection. The injectable gentamicin/oral azithromycin combination was 100% effective in curing genital gonorrhoea infections, while the gemifloxacin/azithromycin pill combination was 99.5% effective. Both combinations cured 100% of infections of the throat and rectum, the researchers noted.
However, many patients in both arms of the study reported unpleasant side effects, including nausea, diarrhoea and abdominal discomfort/pain or vomiting.
The study, scheduled for presentation this week at a meeting of the International Society for Sexually Transmitted Diseases Research in Vienna, Austria, was conducted by the CDC and the US National Institutes of Health.
"These trial results are an exciting step in the right direction in the fight against drug-resistant gonorrhoea," Dr Gail Bolan, director of CDC's division of STD prevention, said in an agency news release. "But patients need more oral options with fewer side effects. It is imperative that researchers and pharmaceutical companies prioritize research to continue to identify new, effective, better-tolerated drugs and drug combinations."
Additional measures to stay ahead of resistant gonorrhoea are critical, Dr Anthony Fauci, director of NIH's National Institute of Allergy and Infectious Diseases, said in the news release. "For example, a point-of-care drug susceptibility test would help providers know at the time of diagnosis which treatment regimen will be most effective," he said.
"Progress toward a vaccine is urgently needed," Fauci added.
These findings do not change current gonorrhoea treatment guidelines. The CDC recommends only one first-line treatment regimen: injectable ceftriaxone, in combination with one of two other antibiotics in pill form, either azithromycin or doxycycline. This therapy is highly effective in treating gonorrhoea and causes limited side effects.
Ceftriaxone is in the same class of antibiotics as cefixime, a pill that has lost effectiveness against the sexually transmitted disease. Earlier this year, Canadian researchers reported on a study of nearly 300 people infected with Neisseria gonorrhoeae that found a treatment failure rate of nearly 7% in people treated with cefixime. Last August the CDC advised doctors to stop using cefixime to treat gonorrhoea, and instead use injections of ceftriaxone.
However, doctors may consider using the treatments assessed in this new study as alternative options when ceftriaxone can't be used, such as in the case of a severe allergy, the CDC said. The agency says it will consider the study's findings for inclusion in future treatment guidelines.
To help prevent gonorrhoea, people who are sexually active should use condoms consistently and correctly, and limit the number of sex partners, the CDC states.
The data and conclusions of research presented at medical meetings should be viewed as preliminary until published in a peer-reviewed journal.
The U.S. National Institute of Allergy and Infectious Diseases has more about gonorrhoea.