A simplified once-weekly treatment regimen using oral secnidazole granules demonstrated superior efficacy in preventing bacterial vaginosis recurrence compared to current CDC-recommended therapies, according to results presented at the 2025 American College of Obstetricians and Gynecologists Annual Clinical and Scientific Meeting.
The prospective longitudinal pilot study, led by Dr. Chemen M. Neal from Indiana University School of Medicine, enrolled 24 women aged 18-50 years with recurrent bacterial vaginosis. After excluding ineligible patients and those who failed initial therapy, 15 participants entered the suppressive treatment phase, receiving 2g of oral secnidazole granules once weekly for 16 weeks, followed by a 3-month post-treatment observation period.
Significant Reduction in Recurrence Rates
The study achieved a recurrence rate of only 20% (3 of 15 participants) over the total 28-week study period. This represents a marked improvement compared to historic recurrence rates cited in CDC guidelines, which range from 35% to 70%. Specifically, the researchers noted previous studies showing recurrence rates of 51% (26/51 patients), 70% (7/10 patients), and 35% with current standard treatments.
Diagnosis and treatment response were assessed using established clinical criteria, including Amsel's criteria (score of 3 or higher) and Nugent score (7 or greater). The most frequently reported side effect among study participants was yeast infection.
Addressing Treatment Compliance Challenges
Current CDC guidelines for recurrent bacterial vaginosis recommend complex regimens including metronidazole 500 mg orally twice daily for 7 days, metronidazole gel 0.75% intravaginally once daily for 5 days, or clindamycin cream 2% intravaginally at bedtime for 7 days. The study authors emphasized that "patient compliance with complicated treatment regimens is a barrier to successful outcomes" and stressed that simplified treatment protocols could improve patient adherence and reduce recurrent disease.
Dr. Neal highlighted the practical challenges patients face with traditional BV regimens, noting that current methods often involve daily oral antibiotic administration followed by twice-weekly doses, or intravaginal gels that can cause discomfort. In some cases, both oral and intravaginal treatments are prescribed simultaneously, further increasing the risk of treatment non-adherence.
Pharmacological Advantages
Secnidazole is an orally administered broad-spectrum nitroimidazole antimicrobial currently approved for treating bacterial vaginosis and trichomoniasis. While structurally related to metronidazole and tinidazole, secnidazole exhibits superior oral absorption and a longer terminal elimination half-life, which may contribute to its effectiveness in suppressive therapy.
Clinical Impact and Market Implications
Bacterial vaginosis affects approximately 29% of reproductive-aged women in the United States, making it the most common cause of vaginal discharge in this population. Beyond symptoms of discharge, odor, and irritation that can lead to embarrassment and social withdrawal, BV is associated with serious complications including adverse birth outcomes, increased risk of HIV and other sexually transmitted infections, and pelvic inflammatory disease.
Recurrence within 6 months has been reported in up to 50% of women treated for BV, highlighting the significant unmet medical need for effective suppressive therapies. According to Evofem Biosciences, the manufacturer of secnidazole oral granules (SOLOSEC), the negative outcomes associated with BV have generated increased interest in therapeutic options, with a projected U.S. market of $1 billion for BV treatments by 2033.
Clinical Recommendations
Dr. Neal emphasized the importance of accurate BV diagnosis, noting that patients are often misdiagnosed. She recommended that clinical evaluations should include detailed patient history, in-office microscopy, and proper use of testing modalities to ensure accurate diagnosis.
"When they do [receive an accurate diagnosis], to really partner with their patients and let them know that recurrent bacterial vaginosis can be difficult to get rid of, and that long-term suppressive therapy seems to be the best route," Neal concluded.
The trial represents one of the first studies to assess secnidazole's efficacy specifically against recurrent bacterial vaginosis, as the drug is currently approved only for acute, non-recurrent cases. The findings suggest potential for expanding secnidazole's indication to include long-term suppressive treatment of recurrent bacterial vaginosis.
