Trial Outcomes & Findings for Doxy-Post-exposure Prophylaxis (NCT NCT05853120)
NCT ID: NCT05853120
Last Updated: 2025-09-11
Results Overview
Rectal biopsies were collected 24 hours after administration of the initial dose of doxycycline
Recruitment status
COMPLETED
Study phase
PHASE4
Target enrollment
45 participants
Primary outcome timeframe
Day 2
Results posted on
2025-09-11
Participant Flow
Participants were recruited from Emory Healthcare System in Atlanta, Georgia, USA. Participant enrollment began May 31, 2023, and all follow-up was completed by December 24, 2024.
Participant milestones
| Measure |
Doxycycline 100 mg
Doxycycline 100mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 1
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
Doxycycline 200 mg
Doxycycline - 200 mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 10
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
|---|---|---|
|
Overall Study
STARTED
|
26
|
19
|
|
Overall Study
COMPLETED
|
14
|
13
|
|
Overall Study
NOT COMPLETED
|
12
|
6
|
Reasons for withdrawal
| Measure |
Doxycycline 100 mg
Doxycycline 100mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 1
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
Doxycycline 200 mg
Doxycycline - 200 mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 10
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
|---|---|---|
|
Overall Study
Lost to Follow-up
|
4
|
4
|
|
Overall Study
Physician Decision
|
3
|
0
|
|
Overall Study
Withdrawal by Subject
|
5
|
2
|
Baseline Characteristics
Doxy-Post-exposure Prophylaxis
Baseline characteristics by cohort
| Measure |
Doxycycline 100 mg
n=26 Participants
Doxycycline 100mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 1
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
Doxycycline 200 mg
n=19 Participants
Doxycycline - 200 mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 10
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
Total
n=45 Participants
Total of all reporting groups
|
|---|---|---|---|
|
Age, Categorical
<=18 years
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Age, Categorical
Between 18 and 65 years
|
26 Participants
n=5 Participants
|
19 Participants
n=7 Participants
|
45 Participants
n=5 Participants
|
|
Age, Categorical
>=65 years
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Age, Continuous
|
40.7 years
STANDARD_DEVIATION 12.1 • n=5 Participants
|
35.4 years
STANDARD_DEVIATION 9.2 • n=7 Participants
|
38.5 years
STANDARD_DEVIATION 11.2 • n=5 Participants
|
|
Sex: Female, Male
Female
|
7 Participants
n=5 Participants
|
10 Participants
n=7 Participants
|
17 Participants
n=5 Participants
|
|
Sex: Female, Male
Male
|
19 Participants
n=5 Participants
|
9 Participants
n=7 Participants
|
28 Participants
n=5 Participants
|
|
Ethnicity (NIH/OMB)
Hispanic or Latino
|
1 Participants
n=5 Participants
|
1 Participants
n=7 Participants
|
2 Participants
n=5 Participants
|
|
Ethnicity (NIH/OMB)
Not Hispanic or Latino
|
25 Participants
n=5 Participants
|
18 Participants
n=7 Participants
|
43 Participants
n=5 Participants
|
|
Ethnicity (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
1 Participants
n=5 Participants
|
1 Participants
n=7 Participants
|
2 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Asian
|
1 Participants
n=5 Participants
|
2 Participants
n=7 Participants
|
3 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Black or African American
|
13 Participants
n=5 Participants
|
9 Participants
n=7 Participants
|
22 Participants
n=5 Participants
|
|
Race (NIH/OMB)
White
|
8 Participants
n=5 Participants
|
6 Participants
n=7 Participants
|
14 Participants
n=5 Participants
|
|
Race (NIH/OMB)
More than one race
|
3 Participants
n=5 Participants
|
1 Participants
n=7 Participants
|
4 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Region of Enrollment
United States
|
26 Participants
n=5 Participants
|
19 Participants
n=7 Participants
|
45 Participants
n=5 Participants
|
PRIMARY outcome
Timeframe: Day 2Population: Participants who completed the corresponding study visit and provided samples for processing.
Rectal biopsies were collected 24 hours after administration of the initial dose of doxycycline
Outcome measures
| Measure |
Doxycycline 100 mg
n=16 Participants
Doxycycline 100mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 1
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
Doxycycline 200 mg
n=11 Participants
Doxycycline - 200 mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 10
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
|---|---|---|
|
Doxycycline Concentrations in Rectal Tissues
|
0.863 µg/g
Interval 0.4 to 7.459
|
2.193 µg/g
Interval 1.283 to 3.766
|
PRIMARY outcome
Timeframe: Day 2Population: Participants who completed the corresponding study visit and provided samples for processing
Vaginal biopsies collected 24 hours after administration of the initial dose of doxycycline
Outcome measures
| Measure |
Doxycycline 100 mg
n=5 Participants
Doxycycline 100mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 1
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
Doxycycline 200 mg
n=4 Participants
Doxycycline - 200 mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 10
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
|---|---|---|
|
Doxycycline Concentrations in Vaginal Tissues
|
0.592 µg/g
Interval 0.204 to 0.662
|
1.214 µg/g
Interval 0.616 to 1.585
|
PRIMARY outcome
Timeframe: Day 15Population: Participants who completed the corresponding study visit and provided samples for processing.
Self-collected swabs and rectal biopsies were collected 24 hours after administration of the fifth dose of doxycycline
Outcome measures
| Measure |
Doxycycline 100 mg
n=14 Participants
Doxycycline 100mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 1
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
Doxycycline 200 mg
n=6 Participants
Doxycycline - 200 mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 10
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
|---|---|---|
|
Doxycycline Concentrations in Rectal Tissues After the Fifth Dose of Doxycycline
|
0.951 µg/g
Interval 0.359 to 7.429
|
1.612 µg/g
Interval 1.222 to 3.517
|
PRIMARY outcome
Timeframe: Day 15Population: Participants who completed the corresponding study visit and provided samples for processing.
Self-collected swabs and vaginal biopsies were collected 24 hours after administration of the fifth dose of doxycycline
Outcome measures
| Measure |
Doxycycline 100 mg
n=4 Participants
Doxycycline 100mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 1
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
Doxycycline 200 mg
n=2 Participants
Doxycycline - 200 mg Participants will receive the first assigned dose of Doxycycline at the clinic on days 0 and 3 at the clinic. The other three doses of the medication will be taken at home on days 7 and 10
Doxycycline: Doxycycline is used to treat or prevent infections that are strongly suspected to be caused by bacteria; it is an antimicrobial drug indicated for bacterial infections such as sexually transmitted infections. Doxycycline (DOX) will be given orally at 100 and 200 mg doses.
|
|---|---|---|
|
Doxycycline Concentrations in Vaginal Tissues Collected 24 Hours After the Fifth Dose of Doxycycline
|
0.590 µg/g
Interval 0.106 to 1.119
|
1.534 µg/g
Interval 1.528 to 1.54
|
OTHER_PRE_SPECIFIED outcome
Timeframe: Throughout study up to 3 months after fifth doseBlood samples will be taken at each in person visit
Outcome measures
Outcome data not reported
OTHER_PRE_SPECIFIED outcome
Timeframe: Throughout study up to 3 months after fifth doseUrine samples will be taken at each in person visit
Outcome measures
Outcome data not reported
OTHER_PRE_SPECIFIED outcome
Timeframe: Throughout study up to 3 months after fifth doseSelf-collected swab samples will be collected 24 hours after administration of the first dose.
Outcome measures
Outcome data not reported
OTHER_PRE_SPECIFIED outcome
Timeframe: Throughout study up to 3 months after fifth doseSelf-collected vaginal swabs will be collected at each in person visit
Outcome measures
Outcome data not reported
OTHER_PRE_SPECIFIED outcome
Timeframe: Throughout study up to 3 months after fifth doseSelf-collected and staff assisted vaginal swabs will be collected at each in person visit
Outcome measures
Outcome data not reported
OTHER_PRE_SPECIFIED outcome
Timeframe: Throughout study up to 3 months after fifth doseStaff-Assisted urethral and glans swabs will be collected
Outcome measures
Outcome data not reported
Adverse Events
Doxycycline 100 mg
Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths
Doxycycline 200 mg
Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths
Serious adverse events
Adverse event data not reported
Other adverse events
Adverse event data not reported
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place