Bacterial vaginosis (BV), an inflammatory condition caused by the proliferation of “bad” bacteria naturally found in the vagina, can affect up to half the women of reproductive age worldwide. Despite treatment with antibiotics, up to three in four women get recurrent infections within three months. But injecting a ‘good’ bacterium to subdue its deleterious peers can slash that high recurrence rate by a third, new clinical trial data suggest.
A 228-patient, placebo-controlled study conducted by NIH researchers evaluated the effect of Lactin-V, a ‘good’ bacterium product packaged for that purpose by California-based company Osel. The product, which is formulated as a powder and called CTV-05, was injected into the vagina using a plastic device that resembles a tampon applicator — after patients were treated with a course of the antibiotic metronidazole in gel form.
At week 24, there were 27% fewer cases of BV, a statistically significant reduction, among those who got CTV-05. No evidence emerged suggesting that Lactin-V causes any local or systemic side effects.
If subsequent studies confirm these findings, “this is the greatest advance in about 40 years,” the study’s chief author Craig Cohen, a professor of obstetrics, gynecology and reproductive sciences at the University of California, San Francisco, told Reuters.
Data also showed that among women who injected CTV-05, the Lactin-V bacterium was detected in 79% of women at week 12 and 48% at week 24. In the placebo group, the bacterium was found 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 wrote in the New England Journal of Medicine, where the study was published on Wednesday.
The study was funded by the NIH, although Osel provided CTV-05, which is also being tested as a treatment for recurrent urinary tract infections by the company. A late-stage BV trial is being planned by the NIH team.
Lactin-V, or Lactobacillus crispatus, is a strain of bacteria that has long known to be a beneficial component of the vaginal microbiome. In a recent study led by Jacques Ravel, who serves as the co-editor-in-chief of the journal Microbiome, found that the diversity of species of L. crispatus is in the region of 5,000.
That finding, Ravel explained in a previous interview with Endpoints News, has major implications.
“From one woman to another, they might carry that same species, but it’s often not the same strain,” he said. “What this means is that this concept of one strain solving all the problems is kind of gone. And that each woman actually has a microbiome, even though it’s dominated by a species, that species is represented by many, many different strains. So it’s almost like a little consortium of strains that are together — from the same species — but those strains work together in providing different functions. The whole consortium of all those strains together makes them stronger.”