Experimental treatment lowers recurrence risk of bacterial vaginosis in phase 2 test

(Reuters Health) - Researchers say they have cut the recurrence rate of bacterial vaginosis by one third using an experimental treatment that injects a bacterium known as Lactin-V into the vagina to crowd out the noxious organisms that cause the condition.

In a phase 2b test of 228 women who had just completed a course of vaginal metronidazole gel, the recurrence rate at 12 weeks was 30% with Lactin-V versus 45% with a placebo (P=0.01).

At week 24, there were 27% fewer cases of bacterial vaginosis among those getting the treatment. There was no evidence that Lactin-V causes any local or systemic side effects.

If further studies confirm the findings, “this is the greatest advance in about 40 years,” chief author Dr. Craig Cohen, a professor of obstetrics, gynecology and reproductive sciences at the University of California, San Francisco, told Reuters Health in a telephone interview.

The findings were published online Wednesday in The New England Journal of Medicine. The team is planning a phase 3 trial of the treatment, which involves the naturally-occurring bacterium Lactobacillus crispatus CTV-05.

“We’re trying to prevent recurrence by establishing a healthy microbiome” that doesn’t produce the discharge, foul odor, vaginal itching and burning sensation of urination that can be the hallmarks of vaginal vaginosis (BV), he said.

“Millions of women in the U.S. and around the world have BV and it certainly affects your quality of life,” said Dr. Cohen.

BV affects up to half of women worldwide at some point in their reproductive years. Recurrence rates after three months can be as high as 75%. In this study, more than half the women said they had already experienced at least five episodes of BV.

The treatment is in the form of a powder that is injected into the vagina using a plastic device with a plunger that looks similar to a tampon applicator. But first, patients need to be treated for five days with metronidazole, which “knocks down the bad guys and opens up the niche to allow the good bacteria to colonize the vagina,” Dr. Cohen said.

During the first week of therapy, patients were instructed to inject Lactin-V four times per day, followed by twice-weekly doses for 10 weeks.

Among women who received the treatment, the Lactin-V bacterium was detected in 79% of women at week 12 and 48% at week 24. In the placebo group, it was present in 6% of women during week 12 and 2% at week 24.

“Although combination metronidazole-probiotic regimens have been tested previously and some have been shown to reduce the risk of recurrence of bacterial vaginosis, the trials have generally been small and have lacked the use of standardized methods, including objective outcome measures for bacterial vaginosis recurrence and colonization by the active trial medication,” the researchers said.

The treatment is being developed by Osel Inc., based in Mountain View, California, which provided the powder but did not pay for the study. It was funded by the National Institutes of Health. The powder is also being tested as a treatment for recurrent urinary tract infections, according to the company’s website.

All of the volunteers had to test negative for sexually-transmitted disease before being allowed to participate.

SOURCE: The New England Journal of Medicine, online May 13, 2020