Trial Outcomes & Findings for A Study Assessing Colonisation & Immunogenicity After Nasal Inoculation With N. Lactamica and Eradication on Day 4 or 14 (NCT NCT03549325)
NCT ID: NCT03549325
Last Updated: 2026-02-12
Results Overview
Measure any rise in serological specific antibodies from samples taken at the start of the study (Day 0) and samples taken on Day 14 post inoculation and Day 28 post antibiotic eradication (Group 1 = Day 32 or Group 2 = Day 42)
Recruitment status
TERMINATED
Study phase
NA
Target enrollment
21 participants
Primary outcome timeframe
Up to 42 Days
Results posted on
2026-02-12
Participant Flow
Healthy adult volunteers were recruited according to a REC approved recruitment strategy between 3/3/17 and 14/4/20. Participants attended a face to face screening visit at NIHR Southampton CRF to obtain informed consent and determine eligiblity
All enrolled participants were allocated to a group upon enrolment
Participant milestones
| Measure |
Group 1
Nasal drops containing Neisseria lactamica are administered at Day 0 by the study doctor.
Eradication therapy with the antibiotic Ciprofloxacin given on Day 4, unless required sooner.
Follow up visits occur on Days 5, 14 and 32.
|
Group 2
Nasal drops containing Neisseria lactamica are administered at Day 0 by the study doctor.
Follow up visits on Day 4 and 7 to check for N. lactamica carriage. Eradication therapy with the antibiotic Ciprofloxacin given on Day 14, unless required sooner.
Follow up visits occur on Days 15, 24 and 42.
|
|---|---|---|
|
Overall Study
STARTED
|
13
|
8
|
|
Overall Study
COMPLETED
|
12
|
7
|
|
Overall Study
NOT COMPLETED
|
1
|
1
|
Reasons for withdrawal
| Measure |
Group 1
Nasal drops containing Neisseria lactamica are administered at Day 0 by the study doctor.
Eradication therapy with the antibiotic Ciprofloxacin given on Day 4, unless required sooner.
Follow up visits occur on Days 5, 14 and 32.
|
Group 2
Nasal drops containing Neisseria lactamica are administered at Day 0 by the study doctor.
Follow up visits on Day 4 and 7 to check for N. lactamica carriage. Eradication therapy with the antibiotic Ciprofloxacin given on Day 14, unless required sooner.
Follow up visits occur on Days 15, 24 and 42.
|
|---|---|---|
|
Overall Study
Withdrawal by Subject
|
1
|
1
|
Baseline Characteristics
Race and Ethnicity were not collected from any participant.
Baseline characteristics by cohort
| Measure |
Group 1
n=13 Participants
Nasal drops containing Neisseria lactamica are administered at Day 0 by the study doctor.
Eradication therapy with the antibiotic Ciprofloxacin given on Day 4, unless required sooner.
Follow up visits occur on Days 5, 14 and 32.
|
Group 2
n=8 Participants
Nasal drops containing Neisseria lactamica are administered at Day 0 by the study doctor.
Follow up visits on Day 4 and 7 to check for N. lactamica carriage. Eradication therapy with the antibiotic Ciprofloxacin given on Day 14, unless required sooner.
Follow up visits occur on Days 15, 24 and 42.
|
Total
n=21 Participants
Total of all reporting groups
|
|---|---|---|---|
|
Age, Continuous
|
33 Years
n=13 Participants
|
29 Years
n=8 Participants
|
31 Years
n=21 Participants
|
|
Sex: Female, Male
Female
|
8 Participants
n=13 Participants
|
8 Participants
n=8 Participants
|
16 Participants
n=21 Participants
|
|
Sex: Female, Male
Male
|
5 Participants
n=13 Participants
|
0 Participants
n=8 Participants
|
5 Participants
n=21 Participants
|
|
Race and Ethnicity Not Collected
|
—
|
—
|
0 Participants
Race and Ethnicity were not collected from any participant.
|
|
Specific IgG titres
Nlac-specific IgG titre
|
5.3 Antibody titre
n=6 Participants • Serological assessment only conducted in those participants in each group who were colonised and with serum samples available at each timepoint
|
4.6 Antibody titre
n=6 Participants • Serological assessment only conducted in those participants in each group who were colonised and with serum samples available at each timepoint
|
5.0 Antibody titre
n=12 Participants • Serological assessment only conducted in those participants in each group who were colonised and with serum samples available at each timepoint
|
|
Specific IgG titres
Nmen-specific IgG titre
|
22.6 Antibody titre
n=6 Participants • Serological assessment only conducted in those participants in each group who were colonised and with serum samples available at each timepoint
|
10.4 Antibody titre
n=6 Participants • Serological assessment only conducted in those participants in each group who were colonised and with serum samples available at each timepoint
|
17.1 Antibody titre
n=12 Participants • Serological assessment only conducted in those participants in each group who were colonised and with serum samples available at each timepoint
|
PRIMARY outcome
Timeframe: Up to 42 DaysPopulation: Participants analysed are only those colonised in each group.
Measure any rise in serological specific antibodies from samples taken at the start of the study (Day 0) and samples taken on Day 14 post inoculation and Day 28 post antibiotic eradication (Group 1 = Day 32 or Group 2 = Day 42)
Outcome measures
| Measure |
Day 0
n=6 Participants
Antigen specific IgG titres in serum prior to inoculation
|
Day 14
n=6 Participants
Antigen specific IgG titres in serum 14 days after inoculation
|
Eradication + 28
n=6 Participants
Antigen specific IgG titres in serum 28 days after eradication
|
|---|---|---|---|
|
Measure the Antibodies, by Serological Antibody Titration, of Short Term Colonisation and Longer Colonisation
Nlac-IgG Group 2
|
4.6 Titres of antigen specific IgG
Interval 3.2 to 9.5
|
13.4 Titres of antigen specific IgG
Interval 9.3 to 14.7
|
10.3 Titres of antigen specific IgG
Interval 7.7 to 13.1
|
|
Measure the Antibodies, by Serological Antibody Titration, of Short Term Colonisation and Longer Colonisation
Nlac-IgG Group 1
|
5.3 Titres of antigen specific IgG
Interval 3.3 to 6.4
|
5.5 Titres of antigen specific IgG
Interval 3.9 to 6.6
|
5.6 Titres of antigen specific IgG
Interval 4.6 to 7.1
|
|
Measure the Antibodies, by Serological Antibody Titration, of Short Term Colonisation and Longer Colonisation
Nmen-IgG Group 1
|
22.6 Titres of antigen specific IgG
Interval 20.4 to 26.1
|
23.7 Titres of antigen specific IgG
Interval 18.5 to 27.8
|
23.2 Titres of antigen specific IgG
Interval 19.4 to 26.6
|
|
Measure the Antibodies, by Serological Antibody Titration, of Short Term Colonisation and Longer Colonisation
Nmen-IgG Group 2
|
10.4 Titres of antigen specific IgG
Interval 8.0 to 13.9
|
17.3 Titres of antigen specific IgG
Interval 9.5 to 33.6
|
14.5 Titres of antigen specific IgG
Interval 9.5 to 22.3
|
SECONDARY outcome
Timeframe: Up to 14 DaysPopulation: Only those participants with at least one throat swab available at a post-challenge visit were included in the analysis
Measure if Neisseria lactamica is able to colonise at or before Day 4 (for group 1) or Day 14 (for group 2) from cultured throat swabs.
Outcome measures
| Measure |
Day 0
n=13 Participants
Antigen specific IgG titres in serum prior to inoculation
|
Day 14
n=7 Participants
Antigen specific IgG titres in serum 14 days after inoculation
|
Eradication + 28
Antigen specific IgG titres in serum 28 days after eradication
|
|---|---|---|---|
|
Measure the Colonisation of Neisseria Lactamica
|
7 Participants
|
6 Participants
|
—
|
SECONDARY outcome
Timeframe: Up to 42 DaysPopulation: Only includes those participants who were colonised at the visit at which they received antibiotic eradication
Record how successful eradication is up to Day 42, using throat swab samples.
Outcome measures
| Measure |
Day 0
n=6 Participants
Antigen specific IgG titres in serum prior to inoculation
|
Day 14
n=4 Participants
Antigen specific IgG titres in serum 14 days after inoculation
|
Eradication + 28
Antigen specific IgG titres in serum 28 days after eradication
|
|---|---|---|---|
|
Measure the Eradication of Neisseria Lactamica
|
6 Participants
|
4 Participants
|
—
|
Adverse Events
Group 1
Serious events: 0 serious events
Other events: 3 other events
Deaths: 0 deaths
Group 2
Serious events: 0 serious events
Other events: 6 other events
Deaths: 0 deaths
Serious adverse events
Adverse event data not reported
Other adverse events
| Measure |
Group 1
n=13 participants at risk
Nasal drops containing Neisseria lactamica are administered at Day 0 by the study doctor.
Eradication therapy with the antibiotic Ciprofloxacin given on Day 4, unless required sooner.
Follow up visits occur on Days 5, 14 and 32.
|
Group 2
n=8 participants at risk
Nasal drops containing Neisseria lactamica are administered at Day 0 by the study doctor.
Follow up visits on Day 4 and 7 to check for N. lactamica carriage. Eradication therapy with the antibiotic Ciprofloxacin given on Day 14, unless required sooner.
Follow up visits occur on Days 15, 24 and 42.
|
|---|---|---|
|
General disorders
Malaise / lethargy / headache
|
0.00%
0/13 • From enrolment until the end of follow up - 32 days post inoculation for Group 1 and 42 days post inoculation for Group 2
Adverse events were reported for all enrolled participants for the duration of their involvement in the study and were defined as per the ClinicalTrials.gov definitions
|
25.0%
2/8 • Number of events 3 • From enrolment until the end of follow up - 32 days post inoculation for Group 1 and 42 days post inoculation for Group 2
Adverse events were reported for all enrolled participants for the duration of their involvement in the study and were defined as per the ClinicalTrials.gov definitions
|
|
Gastrointestinal disorders
Diarrhoea / vomiting
|
0.00%
0/13 • From enrolment until the end of follow up - 32 days post inoculation for Group 1 and 42 days post inoculation for Group 2
Adverse events were reported for all enrolled participants for the duration of their involvement in the study and were defined as per the ClinicalTrials.gov definitions
|
12.5%
1/8 • From enrolment until the end of follow up - 32 days post inoculation for Group 1 and 42 days post inoculation for Group 2
Adverse events were reported for all enrolled participants for the duration of their involvement in the study and were defined as per the ClinicalTrials.gov definitions
|
|
Renal and urinary disorders
Dysuria / cystitis
|
0.00%
0/13 • From enrolment until the end of follow up - 32 days post inoculation for Group 1 and 42 days post inoculation for Group 2
Adverse events were reported for all enrolled participants for the duration of their involvement in the study and were defined as per the ClinicalTrials.gov definitions
|
12.5%
1/8 • From enrolment until the end of follow up - 32 days post inoculation for Group 1 and 42 days post inoculation for Group 2
Adverse events were reported for all enrolled participants for the duration of their involvement in the study and were defined as per the ClinicalTrials.gov definitions
|
|
Respiratory, thoracic and mediastinal disorders
Respiratory tract symptoms
|
23.1%
3/13 • Number of events 4 • From enrolment until the end of follow up - 32 days post inoculation for Group 1 and 42 days post inoculation for Group 2
Adverse events were reported for all enrolled participants for the duration of their involvement in the study and were defined as per the ClinicalTrials.gov definitions
|
25.0%
2/8 • Number of events 3 • From enrolment until the end of follow up - 32 days post inoculation for Group 1 and 42 days post inoculation for Group 2
Adverse events were reported for all enrolled participants for the duration of their involvement in the study and were defined as per the ClinicalTrials.gov definitions
|
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place