CHICAGO — Oral tinidazole, single-dose clindamycin vaginal cream, and lactobacillus-containing products are among the newer therapies for the treatment of bacterial vaginosis, Dr. Paul Nyirjesy said at a conference on vulvovaginal diseases.

Many of the therapies have emerged since the Centers for Disease Control and Prevention's treatment guidelines for bacterial vaginosis (BV) were issued in 2006. Bacterial vaginosis is among the most common vaginal diseases, occurring in about 10% of American women of reproductive age.

Oral tinidazole was approved in the United States in May 2007 for the treatment of BV. A recently published randomized controlled study in 235 women with BV found no significant difference in cure rates when tinidazole was administered as 1 g daily for 5 days or 2 g daily for 2 days (Obstet. Gynecol. 2007;110:302–9).

With use of the very stringent Food and Drug Administration guidelines for cure, 32% of women using the 2-day regimen and 41% using the 5-day regimen were cured, compared with 5.7% receiving placebo, said Dr. Nyirjesy, an investigator for the study. Both tinidazole regimens were superior to placebo.

The CDC's recommended oral therapy for BV is metronidazole 500 mg taken twice a day for 7 days, with clindamycin 300 mg taken twice a day for 7 days listed as an alternative.

Although metronidazole can cause GI complaints in up to 52% of patients, it remains the cheapest therapy for BV, said Dr. Nyirjesy, professor of obstetrics and gynecology and medicine at Drexel University College of Medicine, in Philadelphia. Oral metronidazole 2 g as a single dose was dropped as an alternative oral therapy in the 2006 guidelines because it is clearly inadequate as a treatment for BV, he added.

Single-dose clindamycin 2% vaginal cream is a sustained-release preparation that uses similar technology as single-dose butoconazole-1 cream, which gynecologists may be familiar with, said Dr. Nyirjesy, who has received support from Mission Pharmacal and KV Pharmaceuticals/Ther-RX, which respectively manufacture tinidazole and single-dose clindamycin cream.

In a study of 251 women with BV, clinical cure rates were not significantly different between single-dose clindamycin (Clindesse) and clindamycin 7-day (Cleocin) vaginal creams (88% vs. 83%) (Infect. Dis. Obstet. Gynecol. 2005;13:155–60).

Lactobacillus products would seem to have a role in BV, as the goal of treatment is to reestablish naturally occurring lactobacillus flora in the vagina depleted by BV and to decrease the presence of other species, such as Mobiluncus and G. vaginalis. But study findings have been mixed.

Lactobacillus-impregnated tampons used after a course of clindamycin ovules did not improve cure rates at 2 months in one study (Acta Derm. Venereol. 2005;85:42–6). Early results with the Lactobacillus crispatus CTV-05 strain have not shown a benefit, he said at the conference sponsored by the American Society for Colposcopy and Cervical Pathology.

However, a recent study did report high satisfaction rates for an intravaginal lactobacillus capsule (J. Womens Health 2006;15:1053–60). In a separate study of 32 women with BV, 88% treated with yogurt douches for 7 days during the first trimester of pregnancy were cured, compared with 5% who were not treated (Acta Obstet. Gynecol. Scand. 1993;72:17–9).

“The bottom line is that there is no well-studied product available and no well-demonstrated benefits,” said Dr. Nyirjesy, who noted that most of the lactobacillus products are not available in the U.S.

He suggests individualizing BV therapy based on a variety of variables including cost, convenience, compliance, efficacy, spectrum coverage, and patient preference.

As for whether one antibiotic is better than another, the question has taken on new relevance in light of increasing evidence that not all BV is the same. Research has shown that, compared with other pregnant women, women with BV who have Mobiluncus morphotypes on gram stain are more likely to be symptomatic, have higher numbers of clue cells and positive “whiff” tests, and have vaginal immune and hydrolytic enzyme profiles, which are associated with a greater risk of preterm birth, Dr. Nyirjesy said.

A recent study led by Dr. Nyirjesy (Sex. Transm. Dis. 2007;34:197–202) found that significantly more patients on single-dose 2% clindamycin cream cleared Mobiluncus morphotypes than did patients on multiple doses of 0.75% metronidazole gel (97.5% vs. 80%).

Among women with Mobiluncus at baseline, clinical cure rates were significantly higher in those who received clindamycin (57.5% vs. 27%), but were not significantly different between treatment groups in women with no Mobiluncus at baseline (61% vs. 53%).

That information prompted audience members to question whether they should identify species on wet mount for all of their BV patients.

“The answer is absolutely not,” he said. “The study shows that not all bacterial vaginosis is the same and that there may be different responses to antibiotics in women with BV.”

He stressed that this last was a retrospective study from pooled data, and that marketing efforts notwithstanding, it was a preliminary paper that calls for further investigation.

More Treatments Emerging to Fight Bacterial Vaginosis