RecruitingPhase 4NCT07186465

Microbiome-Modulating Prophylaxis RCT: Antibiotic vs Gynoflor in Postmenopausal Women With Recurrent Cystitis

Evaluating Urinary Microbiome Modulation :An RCT of Antibiotic vs Gynoflor Prophylaxis in Postmenopausal Women With Recurrent Cystitis

Sponsor

Mahidol University

Enrollment

100 participants

Start Date

Sep 11, 2025

Study Type

INTERVENTIONAL

Conditions

Cystitis, Recurrent Urinary Tract Infections

Summary

This open-label, parallel-group randomized controlled trial compares two prophylaxis strategies for recurrent urinary tract infection (rUTI) in postmenopausal women: (1) nightly oral nitrofurantoin 100 mg for 6 months versus (2) a vaginal tablet containing Lactobacillus with ultra-low-dose estriol (Gynoflor: nightly for 14 days, then twice weekly to month 6). Participants (≥40 years) are randomized 1:1 in computer-generated blocks and followed for 6 months. The primary endpoint is the proportion with rUTI recurrence within 6 months. Secondary endpoints include time to first recurrence, antibiotic resistance in breakthrough infections, change in lower urinary tract symptoms (Thai RUTISS), and urinary microbiome measures (Lactobacillus dominance and community diversity by qPCR and 16S rRNA). Key assessments occur at baseline and month 6 (urinalysis, culture, urinary microbiome sampling, and kidney function). Adherence and adverse events are captured via twice-weekly phone/Line contacts. Approximately 100 participants (50 per arm) will be enrolled as a feasibility-sized pilot.

Eligibility

Sex: FEMALEMin Age: 40 Years

Inclusion Criteria6

Female, postmenopausal, age ≥40 years
Clinical history of recurrent urinary tract infection (rUTI) as assessed by the investigator
Able and willing to take assigned prophylaxis for 6 months
Able to attend baseline and Month 6 study visits and provide urine samples
Able to provide written informed consent
Willing and able to complete twice-weekly phone/LINE follow-ups

Exclusion Criteria8

Current symptomatic UTI at enrollment (may be treated and reconsidered after resolution)
Known hypersensitivity or contraindication to nitrofurantoin or to the Lactobacillus/estriol vaginal tablet (Gynoflor) or their excipients; significant renal impairment or other label-based contraindications to nitrofurantoin per local practice
Planned urologic surgery or procedure expected during the 6-month study period
Recent bacterial vaginosis (e.g., within the past month) or active vulvovaginal skin disorders precluding vaginal product use
History of hormone-dependent malignancy (e.g., breast, uterine, or cervical cancer) or unexplained abnormal vaginal bleeding
Significant liver disease (e.g., active hepatitis) or other conditions judged by the investigator to make participation unsafe
Participation in another interventional trial that could interfere with outcomes
Withdrawal of consent or severe adverse event requiring discontinuation

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Interventions

DRUGNitrofurantoin

Nightly oral nitrofurantoin 100 mg for 6 months as prophylaxis for recurrent UTI in postmenopausal women. If symptomatic UTI occurs, treat per standard care and, once resolved, continue assigned prophylaxis to complete 6 months. Monitoring per protocol: baseline and month-6 visits with urinalysis, urine culture, urinary microbiome, and kidney function; twice-weekly phone/Line check-ins for adherence, symptoms, and adverse events.

DRUGGynoflor

Vaginal tablet containing Lactobacillus with ultra-low-dose estriol. Insert 1 tablet nightly for 14 days, then twice weekly through month 6 as prophylaxis against recurrent urinary tract infection. If a symptomatic UTI occurs, treat per standard of care; after resolution, continue assigned prophylaxis to complete 6 months. Monitoring identical to comparator.