Table 1 Characteristics of included trials

Hillier, 2017 [17]

- Parallel design

- three arms

- Phase II

- Country: USA (24 ambulatory gynecology clinics) no single site contributed more than 16% to the study population .

- Follow-up period: Efficacy was evaluated at 21–30 days post treatment.

- Unit of randomization: participant

- Analysis unit: participant

- Enrolled: 215

- Randomized: Secnidazole 1 g: 71 patients, Secnidazole 2 g: 72 patients, and placebo: 72 patient

- Age: Median (min,max): Secnidazole 2 g: 31 (19, 54); Senidazole 1 g: 34 (19, 49), Placebo: 33 (19, 49)

- Number of BV episodes in past 12 months (median(min, max): Secnidazole 2 g: 2 (1, 12); Senidazole 1 g: 1 (1, 13), Placebo: 3 (1, 12)

- Number of BV episodes in past 12 months, n (%):

1) ≤3: Secnidazole 2 g: 41 (66.1); Senidazole 1 g: 44 (68.8), Placebo: 43 (69.4).

2) ≥4: Secnidazole 2 g: 21 (33.9); Senidazole 1 g: 20 (31.3); Placebo: 19 (30.6)

- Baseline nugent score: median (min, max): Secnidazole 2 g:8 (4, 10); Senidazole 1 g: 9 (5, 10), Placebo: 8 (4, 10)

1. Secnidazole 2 g single oral dose

2. Secnidazole 1 g single oral dose

3. Placebo

- Primary:

Clinical cure: based on the 1998 FDA guidance regarding evaluation of treatment for bacterial vaginosis: 1) Normal vaginal discharge, 2) negative 10% potassium hydroxide whiff test, and 3) clue cells less than 20% of total epithelial cells on microscopic examination of the vaginal wet mount using saline at the test of cure visit.

- Secondary:

1) Nugent score (microbiologic cure): with a score of 0–3 considered Lactobacillus-dominant and a score of 4 or greater considered abnormal.

2) Therapeutic cure: defined as meeting the criteria for both clinical and microbiologic cure.

- Safety: were based on the incidence, intensity, and type of adverse events and changes in patients’ physical examination findings, vital signs, and clinical laboratory results,

- Trial registration number: Clinical Trials.gov,

NCT02147899

- A priori sample size estimation: yes

- Trial conduction date: between May 28 and September 5, 2014

- Funding for this study was provided to Magee-Womens

Research Institute (Hillier), Drexel University (Nyirjesy),

Downtown Women’s Health Care (Waldbaum), the University of Alabama (Schwebke), and Tidewater Clinical Research, Inc. (Morgan), by Symbiomix Therapeutics, LLC, Baltimore, MD

Nunez,2005 [16]

- Parallel design

- Two arm

- Phase III

- Country: Manuel Noriega Trigo Hospital, Maracaibo, Venezuela

- Follow-up period: one week

- Unit of randomization: participant

- Analysis unit: participant

- Enrolled: 76

- Randomization: 1 g single oral dose Secnidazole: 44 patients, 2 g single oral dose Secnidazole: 32 patients

- Age: Mean (SD): Secnidazole 2 g: 39.4 (9.9); Senidazole 1 g: 41.1 (11.6)

- Number of BV episodes in past 12 months: Not reported

- Baseline nugent score: Not reported

1. single oral dose of Secnidazole 1 g

2. single oral dose of Secnidazole 2 g

- Primary:

clinical cure: defined as an absence of the characteristic symptoms of BV (bad odor and a grossly abnormal discharge), and at least 2 of the following: vaginal pH less than 4.5, no fish odor on addition of KOH, and no G. vaginalis or clue cells on wet-mount examination.

- Secondary:

cytologic cure: was defined as an absence of G. vaginalis on a Pap smear

- A priori sample size estimation: No

- Trial conduction date: Not reported

- Sponsor: Not reported

Bohbot, 2010 [13]

- Parallel design

- Two arm

- Phase III

- Country: France: Multicenter (27 centers)

- Follow-up period: Assessed after 14 days and after 28 days

- Unit of randomization: participant

- Analysis unit: participant

- Number enrolled: 577

- Randomized:

1) metronidazole group: 237 in modified intention to treat analysis group and 2) Secnidazole group: 243 in modified intention to treat analysis group

- Age: mean age: 36 years in both groups

- Number of BV episodes in past 12 months:

Approximately 28% of patients (secnidazole: 27.2%; metronidazole: 28.6%) had experienced at least one episode of BV during the two years preceding inclusion.

- Baseline nugent score: Not reported

1. Intervention: 500 mg metronidazole twice per day for 7 days

2. Control: single oral dose of Secnidazole 2 g

- Primary outcomes:

1) Clinical cure: was defined as the normalisation of the three Amsel criteria and 2) bacteriological cure: was defined as a Nugent score lower or equal than three

- Secondary outcomes:

therapeutic success at D14, clinical cure at D14 and D28, bacteriological cure at D14 and D28, mean time to symptom disappearance, and safety

- Safety assessments:

Safety was assessed on the basis of adverse events reported

- Trial registration number: Not reported

- Trial conduction date: between March 2007 and July 2008

Saracoglu, 1998 [22]

- Parallel design

- 8 arms

- Phase III

Country: Turky: Ankara Numune Hospital Obstetrics and Gynecology Outpatient Clinic

- Follow-up period: Assessed during first week and after 30–40 days “We called the patients to inform us about their symptoms after the first week and all the patients visited the clinic within 30–40 days for evaluation of the clinical and laboratory results”

- Unit of randomization: participant

- Analysis unit: participant

- Enrolled: 152

- Randomized:

1) Oral ornidazole: 34 pts.

2) Vaginal ornidazole: 21

3) Oral +vaginal ornidazole: 14

4) Oral secnidazole: 29

5) Oral secnidazole + vaginal ornidazole: 10

6) Oral secnidazole + vaginal metronidazole: 11

7) Oral ornidazole + vaginal metronidazole: 10

8) Vaginal metronidazole: 23

- Age: The ages of the patients in the treatment groups ranged between 19 and 45 with no statistical difference in between.

- Number of BV episodes in past 12 months: Not reported

- Baseline nugent score: Not reported

1. oral single dose 2 g Secnidazole

2. “oral secnidazole 2 g in a single dose and vaginal ornidazole 500 mg/day for 5 days”

3. “oral secnidazole 2 g in a single dose and vaginal metronidazole 2X

500 mg for 7 days”

4. “oral ornidazole 2X500 mg/day for 5 days and vaginal metronidazole

2X500 mg/day for 7 days;”

5. “vaginal metronidazole

2X500 mgrday for 7 days”

6. oral ornidazole 2 X 500 mg /day for 5 days

7. vaginal ornidazole 500 mg/day for 5 days

8. Oral + vaginal ornidazole for 5 days

Clinical cure: Absence of symptoms, vaginal discharge resulting from bacterial vaginosis and clue cells was accepted as cure.

- Trial registration number: Not reported

- A priori sample size estimation: no

- Trial conduction date: between January and May 1996

- Sponsor: Not reported

- Role of sponsor: No reported

Schwebke, 2017 [20]

- Parallel design

- Two arms

- Phase III

- Country: USA: Multicenter (21 center in USA).

- Follow-up period: 21 to 30 days

- Unit of randomization: participant

- Analysis unit: participant

- Enrolled: 164

- Randomized: 1) 107 ptients to Secnidazole 2 g, 2) 57 patients to placebo group

- Age: mean (SD): 1) Secnidazole group: 32 (8.7) and 2) placebo group: 30 (7.6)

- Number of BV episodes in past 12 months: Mean (SD): 1) Secnidazole group: 3 (2.4) and 2) Placebo: 3 (2.6)

- Number of BV episodes in past 12 months, n (%):1) ≤3: Secnidazole 2 g:83 (77.6), Placebo: 43 (75.4) . 2) ≥4: Secnidazole 2 g: 24 (22.4); Placebo: 14 (24.6)

- Baseline Nugent score: mean (SD): 1) Secnidazole gourp: 8 (1.8); Placebo gourp: 9 (1.3)

1. oral single dose 2 g Secnidazole

2. placebo

- Primary: “Proportion of clinical outcome responders (CORs):

Normal discharge, negative KOH whiff test, and clue cells < 20% at TOC/EOS visit (study days 21–30)

- Secondary: “An alternate definition of responder defined as:

Normal discharge after treatment or abnormal discharge that is inconsistent with BV; negative KOH whiff test; clue cells < 20% assessed at the interim visit (study days 7–14) and TOC/EOS (study days 21–30)

- Safety: “Rates of adverse events (AEs), serious AEs, vital signs, physical examination findings, and laboratory test results

- Trial registration number: NCT02418845

- A priori sample size estimation: yes

- Trial conduction date: April 16, 2015 to March 30, 2016

- Sponsor: The study was funded by Symbiomix Therapeutics.

Dr. Schwebke received grant

Thulkar, 2012 [21]

- Parallel design

- Four arms

- Phase III

- Country: Department of Obstetrics and Gynecology, All India Institute of Medical Sciences, New Delhi, India

- Follow-up period: four weeks

- Unit of randomization: participant

- Analysis unit: participant

- Enrolled: 344

- Randomized: 86 patients to each group

-Age: mean (SD): 27.9 ± 4.5 years, with a range of 20–40 years

- Number of BV episodes in past 12 months: Not reported

- Baseline Nugent score: Not reported

1. oral single dose of Secnidazole (2 g)

2. oral single dose of Metronidazole (2 g)

3. oral single dose of Tinidazole (2 g)

4. oral single dose of Ornidazole (1.5 g)

- Primary: Cure rate using Amsel criteria: Complete cure was considered when none of the four criteria were present. Improvement in the disease was considered when only one criterion was present. Partial cure was labelled when two criteria were present, and failure of treatment was labelled when three or four criteria were present.”

- Secondary: effect on vaginal flora, and recurrence rate

- Trial registration number: This clinical trial was registered at the Clinical Trials Registry-India (CTRI; Reg. No: 2009–001093)

- A priori sample size estimation: yes

- Trial conduction date: from December 2008 to November 2009