Sexually Transmitted Infection (STI) PreventionSPEARNCT06778083
STI Prophylaxis and Emergence of Antimicrobial Resistance
An observational study of Sexually Transmitted Infection (STI) Prevention and Antibiotic Prophylaxis, run by University College, London at 1 site in United Kingdom.
Trial summary
The goal of this observational study is to understand the risk of antibiotic resistance and changes in the human microbiome (bacteria that live inside and on us), if people use antibiotics to prevent sexually transmitted infections (STI prophylaxis, doxycycline post-exposure prophylaxis, or 'doxyPEP'). Read more about this study
- Who is it for?
- Ages 18 years and older, men onlyHealthy volunteers can take part
- Conditions the study is for
- Sexually Transmitted Infection (STI) Prevention, Antibiotic Prophylaxis, Antibiotic Resistance, Bacterial
- How many people
- 108 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 10 Feb 2025to 30 Apr 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Men only
- Healthy volunteers accepted
- Adult, Older adult
Study population: Men-who-have-sex-with men aged ≥ 18 years living in the United Kingdom. Target of 108 participants, with minimum 40 participants living with HIV.
Who may be able to join
- Aged ≥ 18 years.
- Identifies as a man (cis or trans).
- Has sex with men.
- Able to provide informed consent.
Who cannot join
- Use of an antibiotic other than doxycycline in the 3 months prior to enrolment
- Currently being treated for an STI with doxycycline
- Use of doxycycline within the prior 3 months for an indication other than STI treatment or STI prevention.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United Kingdom1 site, 1 recruiting
- Recruiting
Central and North West London NHS Foundation Trust
London
Manik Kohli, cnwl.spear@nhs.net
Manik Kohli
About this study
The goal of this observational study is to understand the risk of antibiotic resistance and changes in the human microbiome (bacteria that live inside and on us), if people use antibiotics to prevent sexually transmitted infections (STI prophylaxis, doxycycline post-exposure prophylaxis, or 'doxyPEP'). The study will assess how easy and acceptable it is to find antibiotic resistance and microbiome changes in the throats and guts of men-who-have-sex-with-men (MSM) who use STI prophylaxis.
The study will recruit 108 MSM who are using and not using STI prophylaxis. Participants will visit the clinic every 6 months. At each visit, they will provide a throat swab and stool sample, and complete a questionnaire. DNA of the bacteria from the samples will be analysed to identify the bacteria and look for antibiotic resistance.
- Conditions
- Sexually Transmitted Infection (STI) Prevention, Antibiotic Prophylaxis, Antibiotic Resistance, Bacterial, Microbiome, Doxycycline
- Keywords
- DoxyPEP, STI Prophylaxis, Doxycycline, STI Prevention, Antimicrobial Resistance, Antibiotic Resistance, Microbiome, Men-who-have-sex-with-men
- Medical subject headings
- Sexually Transmitted Diseases, Homosexuality
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| DoxyPEP users | Previous use of doxycycline post-exposure prophylaxis within 3 months of baseline visit. | |
| Doxycycline treatment | Previous use of doxycycline for STI treatment within 3 months of baseline visit. Once enrolled all participants may use doxycycline post-exposure prophylaxis. | |
| No antibiotics | No antibiotics within previous 3 months of baseline visit. Once enrolled all participants may use doxycycline post-exposure prophylaxis. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Detection of antimicrobial resistance genes of interest and characterisation of microbiome
The successful detection of antimicrobial resistance genes of interest (tetracycline and other antibiotic classes) and identification of bacterial species (microbiome) and in the oropharynx and gastrointestinal tract.
Measured: From enrolment to 12 months
Secondary outcomes (4)
Detection of differences in prevalence of antimicrobial resistance genes of interest between people using and not using antibiotic STI prophylaxis.
Measured: From enrolment to 12 months
Detection of differences in microbiome between people using and not using antibiotic STI prophylaxis.
Measured: From enrolment to 12 months
Change over time in prevalence of antimicrobial resistance genes of interest between people using and not using antibiotic STI prophylaxis.
Measured: From enrolment to 12 months
Change over time in microbiome between people using and not using antibiotic STI prophylaxis.
Measured: From enrolment to 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Jan 2025
- Study start10 Feb 2025
- Primary completion30 Apr 2027 (estimated)
- Study completion30 Apr 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (6)Papers the sponsor has linked to this study.
- Other trials for Sexually Transmitted Infection (STI) PreventionStudies of the same condition, open and under way.
- More trials run by University College, LondonThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 108 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University College, London
- Sponsor type
- University, hospital or other
- Collaborators
- University of Oxford
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06778083
- Sponsor's protocol ID
- 174194
- Other IDs
- REC Ref: 24/EM/0282
- Acronym
- SPEAR
- Status last verified
- Mar 2025
- First submitted
- 10 Jan 2025
- Last updated
- 27 Mar 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Kohli M, Reid D, Pulford CV, Howarth A, Brown J, Mohammed H, Hughes G, Mercer CH, Saunders J. Choice of antibiotics for prophylaxis of bacterial STIs among individuals currently self-sourcing. Sex Transm Infect. 2022 Mar;98(2):158. doi: 10.1136/sextrans-2021-055310. Epub 2021 Dec 6. No abstract available.
PubMed 34873029Kohli M, Medland N, Fifer H, Saunders J. BASHH updated position statement on doxycycline as prophylaxis for sexually transmitted infections. Sex Transm Infect. 2022 May;98(3):235-236. doi: 10.1136/sextrans-2022-055425. No abstract available.
PubMed 35414633Chu VT, Glascock A, Donnell D, Grabow C, Brown CE, Ward R, Love C, Kalantar KL, Cohen SE, Cannon C, Woodworth MH, Kelley CF, Celum C, Luetkemeyer AF, Langelier CR. Impact of doxycycline post-exposure prophylaxis for sexually transmitted infections on the gut microbiome and antimicrobial resistome. Nat Med. 2025 Jan;31(1):207-217. doi: 10.1038/s41591-024-03274-2. Epub 2024 Oct 3.
PubMed 39363100Molina JM, Charreau I, Chidiac C, Pialoux G, Cua E, Delaugerre C, Capitant C, Rojas-Castro D, Fonsart J, Bercot B, Bebear C, Cotte L, Robineau O, Raffi F, Charbonneau P, Aslan A, Chas J, Niedbalski L, Spire B, Sagaon-Teyssier L, Carette D, Mestre SL, Dore V, Meyer L; ANRS IPERGAY Study Group. Post-exposure prophylaxis with doxycycline to prevent sexually transmitted infections in men who have sex with men: an open-label randomised substudy of the ANRS IPERGAY trial. Lancet Infect Dis. 2018 Mar;18(3):308-317. doi: 10.1016/S1473-3099(17)30725-9. Epub 2017 Dec 8.
PubMed 29229440Molina JM, Bercot B, Assoumou L, Rubenstein E, Algarte-Genin M, Pialoux G, Katlama C, Surgers L, Bebear C, Dupin N, Ouattara M, Slama L, Pavie J, Duvivier C, Loze B, Goldwirt L, Gibowski S, Ollivier M, Ghosn J, Costagliola D; ANRS 174 DOXYVAC Study Group. Doxycycline prophylaxis and meningococcal group B vaccine to prevent bacterial sexually transmitted infections in France (ANRS 174 DOXYVAC): a multicentre, open-label, randomised trial with a 2 x 2 factorial design. Lancet Infect Dis. 2024 Oct;24(10):1093-1104. doi: 10.1016/S1473-3099(24)00236-6. Epub 2024 May 23.
PubMed 38797183Luetkemeyer AF, Donnell D, Dombrowski JC, Cohen S, Grabow C, Brown CE, Malinski C, Perkins R, Nasser M, Lopez C, Vittinghoff E, Buchbinder SP, Scott H, Charlebois ED, Havlir DV, Soge OO, Celum C; DoxyPEP Study Team. Postexposure Doxycycline to Prevent Bacterial Sexually Transmitted Infections. N Engl J Med. 2023 Apr 6;388(14):1296-1306. doi: 10.1056/NEJMoa2211934.
PubMed 37018493
Study at a glance
From the registry record, last updated by the sponsor on 27 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- STI Prophylaxis and Emergence of Antimicrobial Resistance
- ClinicalTrials.gov ID
- NCT06778083
- Acronym / sponsor ID
- SPEAR / 174194
- Conditions
- Sexually Transmitted Infection (STI) Prevention, Antibiotic Prophylaxis, Antibiotic Resistance, Bacterial, Microbiome, Doxycycline
- Keywords
- DoxyPEP, STI Prophylaxis, Doxycycline, STI Prevention, Antimicrobial Resistance, Antibiotic Resistance, Microbiome, Men-who-have-sex-with-men
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 108 participants (estimated)
- Lead sponsor
- University College, LondonUniversity, hospital or other
- Collaborators
- University of Oxford
- Study start
- 10 Feb 2025 (actual)
- Primary completion
- 30 Apr 2027 (estimated)
- Study completion
- 30 Apr 2027 (estimated)
- First posted
- 16 Jan 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this observational study is to understand the risk of antibiotic resistance and changes in the human microbiome (bacteria that live inside and on us), if people use antibiotics to prevent sexually transmitted infections (STI prophylaxis, doxycycline post-exposure prophylaxis, or 'doxyPEP'). The study will assess how easy and acceptable it is to find antibiotic resistance and microbiome changes in the throats and guts of men-who-have-sex-with-men (MSM) who use STI prophylaxis.
The study will recruit 108 MSM who are using and not using STI prophylaxis. Participants will visit the clinic every 6 months. At each visit, they will provide a throat swab and stool sample, and complete a questionnaire. DNA of the bacteria from the samples will be analysed to identify the bacteria and look for antibiotic resistance.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| DoxyPEP users | – | –Previous use of doxycycline post-exposure prophylaxis within 3 months of baseline visit. |
| Doxycycline treatment | – | –Previous use of doxycycline for STI treatment within 3 months of baseline visit. Once enrolled all participants may use doxycycline post-exposure prophylaxis. |
| No antibiotics | – | –No antibiotics within previous 3 months of baseline visit. Once enrolled all participants may use doxycycline post-exposure prophylaxis. |
Who may qualify
- Ages
- 18 years and older
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Men-who-have-sex-with men aged ≥ 18 years living in the United Kingdom. Target of 108 participants, with minimum 40 participants living with HIV.
Key inclusion criteria (4 listed)
- Aged ≥ 18 years.
- Identifies as a man (cis or trans).
- Has sex with men.
- Able to provide informed consent.
Key exclusion criteria (3 listed)
- Use of an antibiotic other than doxycycline in the 3 months prior to enrolment
- Currently being treated for an STI with doxycycline
- Use of doxycycline within the prior 3 months for an indication other than STI treatment or STI prevention.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Detection of antimicrobial resistance genes of interest and characterisation of microbiome
Time frame: From enrolment to 12 months
The successful detection of antimicrobial resistance genes of interest (tetracycline and other antibiotic classes) and identification of bacterial species (microbiome) and in the oropharynx and gastrointestinal tract.
4 secondary outcomes
Detection of differences in prevalence of antimicrobial resistance genes of interest between people using and not using antibiotic STI prophylaxis.
Time frame: From enrolment to 12 months
Detection of differences in microbiome between people using and not using antibiotic STI prophylaxis.
Time frame: From enrolment to 12 months
Change over time in prevalence of antimicrobial resistance genes of interest between people using and not using antibiotic STI prophylaxis.
Time frame: From enrolment to 12 months
Change over time in microbiome between people using and not using antibiotic STI prophylaxis.
Time frame: From enrolment to 12 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Mar 2025.
- Background: PubMed 34873029Kohli M, Reid D, Pulford CV, Howarth A, Brown J, Mohammed H, Hughes G, Mercer CH, Saunders J. Choice of antibiotics for prophylaxis of bacterial STIs among individuals currently self-sourcing. Sex Transm Infect. 2022 Mar;98(2):158. doi: 10.1136/sextrans-2021-055310. Epub 2021 Dec 6. No abstract available.
- Background: PubMed 35414633Kohli M, Medland N, Fifer H, Saunders J. BASHH updated position statement on doxycycline as prophylaxis for sexually transmitted infections. Sex Transm Infect. 2022 May;98(3):235-236. doi: 10.1136/sextrans-2022-055425. No abstract available.
- Background: PubMed 39363100Chu VT, Glascock A, Donnell D, Grabow C, Brown CE, Ward R, Love C, Kalantar KL, Cohen SE, Cannon C, Woodworth MH, Kelley CF, Celum C, Luetkemeyer AF, Langelier CR. Impact of doxycycline post-exposure prophylaxis for sexually transmitted infections on the gut microbiome and antimicrobial resistome. Nat Med. 2025 Jan;31(1):207-217. doi: 10.1038/s41591-024-03274-2. Epub 2024 Oct 3.
- Background: PubMed 29229440Molina JM, Charreau I, Chidiac C, Pialoux G, Cua E, Delaugerre C, Capitant C, Rojas-Castro D, Fonsart J, Bercot B, Bebear C, Cotte L, Robineau O, Raffi F, Charbonneau P, Aslan A, Chas J, Niedbalski L, Spire B, Sagaon-Teyssier L, Carette D, Mestre SL, Dore V, Meyer L; ANRS IPERGAY Study Group. Post-exposure prophylaxis with doxycycline to prevent sexually transmitted infections in men who have sex with men: an open-label randomised substudy of the ANRS IPERGAY trial. Lancet Infect Dis. 2018 Mar;18(3):308-317. doi: 10.1016/S1473-3099(17)30725-9. Epub 2017 Dec 8.
- Background: PubMed 38797183Molina JM, Bercot B, Assoumou L, Rubenstein E, Algarte-Genin M, Pialoux G, Katlama C, Surgers L, Bebear C, Dupin N, Ouattara M, Slama L, Pavie J, Duvivier C, Loze B, Goldwirt L, Gibowski S, Ollivier M, Ghosn J, Costagliola D; ANRS 174 DOXYVAC Study Group. Doxycycline prophylaxis and meningococcal group B vaccine to prevent bacterial sexually transmitted infections in France (ANRS 174 DOXYVAC): a multicentre, open-label, randomised trial with a 2 x 2 factorial design. Lancet Infect Dis. 2024 Oct;24(10):1093-1104. doi: 10.1016/S1473-3099(24)00236-6. Epub 2024 May 23.
- Background: PubMed 37018493Luetkemeyer AF, Donnell D, Dombrowski JC, Cohen S, Grabow C, Brown CE, Malinski C, Perkins R, Nasser M, Lopez C, Vittinghoff E, Buchbinder SP, Scott H, Charlebois ED, Havlir DV, Soge OO, Celum C; DoxyPEP Study Team. Postexposure Doxycycline to Prevent Bacterial Sexually Transmitted Infections. N Engl J Med. 2023 Apr 6;388(14):1296-1306. doi: 10.1056/NEJMoa2211934.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Sexually Transmitted Infection (STI) Prevention and Antibiotic Prophylaxis, run by University College, London at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 27 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Manik Kohli, MBChB MSc (+4420276794466, m.kohli@ucl.ac.uk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Detection of antimicrobial resistance genes of interest and characterisation of microbiome (time frame: From enrolment to 12 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06778083, which also lists 6 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Mar 2025.