Early SyphilisPhase 4NCT05980871
Treatment Responses of Early Syphilis to Ceftriaxone Plus Doxycycline
A Phase 4 study testing Doxycycline, Ceftriaxone and benzathine penicillin G in people with Early Syphilis, run by National Taiwan University Hospital at 1 site in Taiwan.
Trial summary
In a prospective study investigating the prevalence of sexually transmitted infections (STIs) among at-risk people living with HIV (PLWH), the prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae was 24.7% and 12.1%, respectively. Surprisingly, the study found high rates of C. trachomatis and/or N. Read more about this study
- Who is it for?
- Ages 20 years and older
- Conditions the study is for
- Early Syphilis
- What is being tested?
- Doxycycline, Ceftriaxone and benzathine penicillin G
- Type of treatment
- Pill or oral medicine, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 109 participants
- Where
- 1 siteTaiwan
- Study dates
- 10 Mar 2023to 25 Jul 2025
- Phase
- Phase 4
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 20 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- PLWH aged 20 years or more
- PLWH with early syphilis (i.e. primary, secondary, or early latent syphilis), confirmed by a positive rapid plasma reagin (RPR) titer with a reactive Treponema pallidum particle agglutination (TPPA) assay.
- PLWH has provided informed consent
Who cannot join
- PLWH with RPR titers of less than 4
- Exposure to antibiotics with activity against T. pallidum, such as penicillins, third-generation cephems, doxycycline, or macrolides, within the preceding 4 weeks
- A known or suspected infection other than syphilis requiring additional treatment with an antimicrobial active against T. pallidum
- A history of intolerance to penicillin, ceftriaxone, or doxycycline
- Pregnancy
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Treatment Responses of Early Syphilis to Single-dose Ceftriaxone Plus Doxycycline Versus Single-dose Benzathine Penicillin G Plus Doxycycline in People Living With HIV (PLWH)
In a prospective study investigating the prevalence of sexually transmitted infections (STIs) among at-risk people living with HIV (PLWH), the prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae was 24.7% and 12.1%, respectively. Surprisingly, the study found high rates of C. trachomatis and/or N. gonorrhoeae co-infections in PLWH with recent hepatitis C virus (HCV) infection (50%), HBsAg positivity (44%), and early syphilis (36%). Considering the high rate of sexually transmitted co-infections, combination therapy of single-dose ceftriaxone plus 7-day doxycycline for early syphilis may provide convenience and benefit to treatment of N. gonorrhoeae and C. trachomatis co-infections at a single clinic encounter. In the present study, this study aim to compare the efficacy of ceftriaxone plus doxycycline versus benzathine penicillin G (BPG) plus doxycycline as the treatment for early syphilis among PLWH.
Read the detailed description
Enrolled criteria:
- PLWH aged 20 years or more
- PLWH with early syphilis (i.e. primary, secondary, or early latent syphilis), confirmed by a positive rapid plasma reagin (RPR) titer with a reactive Treponema pallidum particle agglutination (TPPA) assay.
- PLWH has provided informed consent *A participant with repeated syphilis can be repeated enrolled after signing an informed consent if the previous episode of early syphilis was successfully treated with achieving at least a 4-fold decrease in RPR titers and 48-week follow-up is completed.
Exclusion criteria:
- PLWH with RPR titers of less than 4
- Exposure to antibiotics with activity against T. pallidum, such as penicillins, third-generation cephems, doxycycline, or macrolides, within the preceding 4 weeks
- A known or suspected infection other than syphilis requiring additional treatment with an antimicrobial active against T. pallidum
- A history of intolerance to penicillin, ceftriaxone, or doxycycline
- Pregnancy
Primary outcome:
Serologic response at month 6 (defined as either a 4-fold or greater decline in RPR titer compared to baseline or being RPR-nonreactive)
Secondary outcomes:
- Microbiologic response of syphilis (defined as T. pallidum PCR Ct value >38) at week 4
- Microbiologic response of bacterial STIs (defined as negative PCR results) at week 4
- Serologic response at months 3 and 12
- Safety of study treatment recorded by using a diary (all adverse events will be coded and graded according to Common Terminology Criteria for Adverse Events [CTCAE] v4.0.)
- Adherence evaluation (the noting of tablet intake in the diary for the 7 days of the treatment period)
- Conditions
- Early Syphilis
- Being tested
- Doxycycline, Ceftriaxone, benzathine penicillin G
- Keywords
- sexually transmitted infection, Treponema pallidum, gonorrhea, chlamydia
- Medical subject headings
- Syphilis, Sexually Transmitted Diseases, Treponemal Infections, Gonorrhea, Chlamydia Infections
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
DoxycyclineDrug
doxycycline (100 mg orally twice daily for 7 days)
CeftriaxoneDrug
Ceftriaxone (1g intramuscularly once)
benzathine penicillin GDrug
benzathine penicillin G (2.4 MU intramuscularly once)
| Study group | Role | What they receive |
|---|---|---|
| single-dose ceftriaxone plus doxycycline | Active comparator | single-dose ceftriaxone (1g intramuscularly once) plus doxycycline (100 mg orally twice daily for 7 days) Receives: Drug: Doxycycline; Drug: Ceftriaxone |
| single-dose BPG plus doxycycline | Active comparator | single-dose BPG (2.4 million unit [MU] intramuscularly once) plus doxycycline (100 mg orally twice daily for 7 days) Receives: Drug: Doxycycline; Drug: benzathine penicillin G |
What is being measured
The primary outcome is the main question the study is designed to answer.
Rate of Serologic Response at Month 6
Serologic response is defined as either a 4-fold or greater decline in RPR titer compared to baseline or being RPR-nonreactive
Measured: Month 6
Secondary outcomes (4)
Rate of Microbiologic Response of Syphilis at Week 4
Microbiologic response of syphilis is defined as T. pallidum PCR Ct value >38
Measured: Week 4
Rate of Microbiologic Response of Bacterial STIs at Week 4
Microbiologic response of bacterial STIs is defined as negative PCR results
Measured: Week 4
Rate of Serologic Response at Month 3
Serologic response is defined as either a 4-fold or greater decline in RPR titer compared to baseline or being RPR-nonreactive
Measured: Month 3
Rate of Serologic Response at Month 12
Serologic response is defined as either a 4-fold or greater decline in RPR titer compared to baseline or being RPR-nonreactive
Measured: Month 12
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Aug 2023
- Study start10 Mar 2023
- Primary completion25 Jul 2025
- Study completion25 Jul 2025
Why it stopped: An error of the sample size calculation occurred. A previous calculation based on a previous trial by Cao et al estimated to assign 150 participants to each group. A corrected calculation showed that 43 participants for each group is sufficient.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Early SyphilisStudies of the same condition, open and under way.
- More trials run by National Taiwan University HospitalThe 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
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 109 participants (actual)
Sponsor and investigators
- Lead sponsor
- National Taiwan University Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Kuan-Yin Lin, Principal investigator, National Taiwan University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05980871
- Sponsor's protocol ID
- 202206138MIND
- Status last verified
- Dec 2025
- First submitted
- 8 Mar 2023
- Last updated
- 25 Feb 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 25 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Treatment Responses of Early Syphilis to Single-dose Ceftriaxone Plus Doxycycline Versus Single-dose Benzathine Penicillin G Plus Doxycycline in People Living With HIV (PLWH)
- ClinicalTrials.gov ID
- NCT05980871
- Acronym / sponsor ID
- 202206138MIND
- Conditions
- Early Syphilis
- Keywords
- sexually transmitted infection, Treponema pallidum, gonorrhea, chlamydia
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: An error of the sample size calculation occurred. A previous calculation based on a previous trial by Cao et al estimated to assign 150 participants to each group. A corrected calculation showed that 43 participants for each group is sufficient.
- Enrolment
- 109 participants (actual)
- Lead sponsor
- National Taiwan University HospitalUniversity, hospital or other
- Study start
- 10 Mar 2023 (actual)
- Primary completion
- 25 Jul 2025 (actual)
- Study completion
- 25 Jul 2025 (actual)
- First posted
- 8 Aug 2023 (actual)
- Results
- Posted 25 Feb 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
In a prospective study investigating the prevalence of sexually transmitted infections (STIs) among at-risk people living with HIV (PLWH), the prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae was 24.7% and 12.1%, respectively. Surprisingly, the study found high rates of C. trachomatis and/or N. gonorrhoeae co-infections in PLWH with recent hepatitis C virus (HCV) infection (50%), HBsAg positivity (44%), and early syphilis (36%). Considering the high rate of sexually transmitted co-infections, combination therapy of single-dose ceftriaxone plus 7-day doxycycline for early syphilis may provide convenience and benefit to treatment of N. gonorrhoeae and C. trachomatis co-infections at a single clinic encounter. In the present study, this study aim to compare the efficacy of ceftriaxone plus doxycycline versus benzathine penicillin G (BPG) plus doxycycline as the treatment for early syphilis among PLWH.
Detailed description
Enrolled criteria:
- PLWH aged 20 years or more
- PLWH with early syphilis (i.e. primary, secondary, or early latent syphilis), confirmed by a positive rapid plasma reagin (RPR) titer with a reactive Treponema pallidum particle agglutination (TPPA) assay.
- PLWH has provided informed consent *A participant with repeated syphilis can be repeated enrolled after signing an informed consent if the previous episode of early syphilis was successfully treated with achieving at least a 4-fold decrease in RPR titers and 48-week follow-up is completed.
Exclusion criteria:
- PLWH with RPR titers of less than 4
- Exposure to antibiotics with activity against T. pallidum, such as penicillins, third-generation cephems, doxycycline, or macrolides, within the preceding 4 weeks
- A known or suspected infection other than syphilis requiring additional treatment with an antimicrobial active against T. pallidum
- A history of intolerance to penicillin, ceftriaxone, or doxycycline
- Pregnancy
Primary outcome:
Serologic response at month 6 (defined as either a 4-fold or greater decline in RPR titer compared to baseline or being RPR-nonreactive)
Secondary outcomes:
- Microbiologic response of syphilis (defined as T. pallidum PCR Ct value >38) at week 4
- Microbiologic response of bacterial STIs (defined as negative PCR results) at week 4
- Serologic response at months 3 and 12
- Safety of study treatment recorded by using a diary (all adverse events will be coded and graded according to Common Terminology Criteria for Adverse Events [CTCAE] v4.0.)
- Adherence evaluation (the noting of tablet intake in the diary for the 7 days of the treatment period)
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| single-dose ceftriaxone plus doxycycline | Active comparator | Drug: Doxycycline, Drug: Ceftriaxonesingle-dose ceftriaxone (1g intramuscularly once) plus doxycycline (100 mg orally twice daily for 7 days) |
| single-dose BPG plus doxycycline | Active comparator | Drug: Doxycycline, Drug: benzathine penicillin Gsingle-dose BPG (2.4 million unit [MU] intramuscularly once) plus doxycycline (100 mg orally twice daily for 7 days) |
Who may qualify
- Ages
- 20 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- PLWH aged 20 years or more
- PLWH with early syphilis (i.e. primary, secondary, or early latent syphilis), confirmed by a positive rapid plasma reagin (RPR) titer with a reactive Treponema pallidum particle agglutination (TPPA) assay.
- PLWH has provided informed consent
Key exclusion criteria (5 listed)
- PLWH with RPR titers of less than 4
- Exposure to antibiotics with activity against T. pallidum, such as penicillins, third-generation cephems, doxycycline, or macrolides, within the preceding 4 weeks
- A known or suspected infection other than syphilis requiring additional treatment with an antimicrobial active against T. pallidum
- A history of intolerance to penicillin, ceftriaxone, or doxycycline
- Pregnancy
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Doxycyclinedoxycycline (100 mg orally twice daily for 7 days) | Drug | single-dose BPG plus doxycycline, single-dose ceftriaxone plus doxycycline |
| CeftriaxoneCeftriaxone (1g intramuscularly once) | Drug | single-dose ceftriaxone plus doxycycline |
| benzathine penicillin Gbenzathine penicillin G (2.4 MU intramuscularly once) | Drug | single-dose BPG plus doxycycline |
Primary outcome
Rate of Serologic Response at Month 6
Time frame: Month 6
Serologic response is defined as either a 4-fold or greater decline in RPR titer compared to baseline or being RPR-nonreactive
4 secondary outcomes
Rate of Microbiologic Response of Syphilis at Week 4
Time frame: Week 4
Rate of Microbiologic Response of Bacterial STIs at Week 4
Time frame: Week 4
Rate of Serologic Response at Month 3
Time frame: Month 3
Rate of Serologic Response at Month 12
Time frame: Month 12
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 25 Feb 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- 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. This study is not recruiting at the moment.
Kuan-Yin Lin principal investigator
National Taiwan University Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Doxycycline, Ceftriaxone and benzathine penicillin G in people with Early Syphilis, run by National Taiwan University Hospital at 1 site in Taiwan.
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 3 inclusion and 5 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: stopped early, as of the sponsor's last update on 25 Feb 2026. 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 Taiwan. 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.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 25 Feb 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Rate of Serologic Response at Month 6 (time frame: Month 6). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 25 Feb 2026.