Microbiome-Modulating Prophylaxis RCT: Antibiotic vs Gynoflor in Postmenopausal Women With Recurrent Cystitis
Trial statusRecruiting
Trial phasePhase 4
Trial typeInterventional
Biological sexFemale
Age40+
SponsorMahidol University
About this trial
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 criteria
This trial does not accept healthy volunteersQualifiers
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
Disqualifiers
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
Trial design
Design model
Parallel
Treatments tested in this trial
Nitrofurantoin
DrugNightly 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.
Gynoflor
DrugVaginal 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.
Treatment groups
100 Participants
are divided into 2 treatment groupsGroup A: Nitrofurantoin ProphylaxisActive comparator 1 intervention
Group B: Gynoflor Vaginal TabletExperimental treatment 1 intervention
Trial outcomes
Primary outcomes
1
Proportion of participants with recurrent UTI within 6 months
Number of participants who experience ≥1 episode of symptomatic urinary tract infection (UTI) during the 6-month prophylaxis period, confirmed by clinical symptoms and positive urine culture per hospital standard. Event counted once per participant; groups compared between arms.
Time frame
Baseline to 6 months after randomizationSecondary outcomes
1
Time to first recurrent UTI
Days from randomization to first symptomatic, culture-confirmed UTI during the 6-month period; participants without an event are censored at 6 months.
Time frame
Baseline to 6 months2
Antibiotic resistance among breakthrough infections
Proportion of bacterial isolates from breakthrough UTIs that are non-susceptible to commonly tested antibiotics per local microbiology reporting.
Time frame
During the 6-month prophylaxis period3
Change in lower urinary tract symptom score (RUTISS, Thai)
Change in Recurrent Urinary Tract Infection Symptom Scale (RUTISS) Section C Severity Score Description: Mean change in the Recurrent Urinary Tract Infection Symptom Scale (RUTISS) Section C total severity score from baseline to Month 6. Section C summarizes four domains (urinary symptoms, urinary presentation, UTI pain/discomfort, bodily sensations). The Overall RUTISS Severity Score is calculated as: sum of Section C responses ÷ 11 × 10, yielding a 0-100 scale. Higher scores = worse symptom/pain severity. Time Frame: Baseline and Month 6. Unit of Measure: Points (0-100). Scale Details: Minimum = 0, Maximum = 100, Higher = worse
Time frame
Baseline and month 64
Lactobacillus abundance by qPCR
Change in Lactobacillus copy number/relative abundance in midstream urine measured by quantitative PCR.
Time frame
Baseline and month 6Sponsors and contacts
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Source ClinicalTrials.gov