ClinicalTrials.gg
CompletedNCT00031499Updated Apr 29, 2013

Azithromycin/Bicillin Syphilis

A Phase 3 interventional study of Azithromycin and Benzathine Penicillin in Syphilis, sponsored by National Institute of Allergy and Infectious Diseases (NIAID). Completed at 10 sites in 2 countries. Open to participants aged 18 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2013-04-29.

Sponsored by National Institute of Allergy and Infectious Diseases (NIAID) · Phase 3, Interventional, and Treatment

Phase
Phase 3
Study type
Interventional
Enrollment
593
Allocation
Randomized
Ages
18 Years to 55 Years
Sex
All
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Study summary

The purpose of this study is to determine if azithromycin, a drug approved for treatment of other infections, is as effective for syphilis (a sexually transmitted disease) as the standard treatment. Approximately 600 healthy adults, who are HIV-negative, ages 18 to 55 years of age, with primary, secondary or early latent syphilis, will participate in this research study. Volunteers will be enrolled in 5 U.S. cities and in Madagascar. Participants will be chosen randomly (by chance) to receive 1 of 2 study drugs: benzathine penicillin given (2 shots in the buttocks) or 4 tablets of azithromycin. Subjects who report a history of a penicillin allergy will be given either 2.0 g of oral azithromycin or 100 mg doxycycline taken orally, twice a day for 14 days. Over 2 years, 10 visits will be required. Procedures will include blood samples, physical exams, and swabs of sores.

Read the detailed description

Syphilis is a disease with a worldwide distribution. It causes genital ulceration, thereby amplifying risk for HIV acquisition and transmission and it may cause congenital infection, spontaneous abortion, and stillbirth if untreated in pregnant women. About one third of all cases, if untreated, result in late sequelae which include neurosyphilis, gumma formation and cardiovascular involvement. This study will be a multi-center, randomized, open-label trial to evaluate the efficacy of azithromycin in treating primary, secondary and early latent syphilis in HIV (Human Immunodeficiency Virus) uninfected volunteers. Up through version 6.0 of this protocol volunteers were only followed for 12 months. The protocol was amended starting with version 7.0 to include follow-up visits at month 18 and 24 in order to capture possible "late failures." Each subject will be randomized into a treatment group. If the subject does not have a self-reported history of penicillin allergy, the subject will be randomized to receive either a single 2.0 gram dose of azithromycin administered orally, or 2.4 million units of benzathine penicillin G administered intramuscularly once. Eligible patients who report a history of penicillin allergy will be randomized (using a separate randomization schedule) to receive either a single dose of azithromycin or doxycycline, 100 milligrams, taken orally, twice a day for 14 days. Block randomization will be used within each clinical center with subjects allocated in equal numbers to either standard therapy or azithromycin. Participants found to be ineligible for study participation after they have been randomized and treated, will be treated again with benzathine penicillin G (or doxycycline if they are allergic to penicillin) and will continue follow-up for safety evaluation. The treatment assignments will not be blinded. No attempt will be made to recruit a sufficient sample size among penicillin allergic subjects to attain the desired power for the primary outcome. Therefore these results will be seen as preliminary to a possible future trial and as confirmatory to the primary comparison. Although the study endpoint will be determined at 6 months, all participants, will have follow-up visits for 2 full years. At the end of the 6 month evaluation period, all participants will have been classified in one of the following groups: cure; clinical response/serological nonresponse; or failure.

02

Conditions studied

  • Syphilis

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Keywords

  • Azithromycin, Syphilis, Penicillin
03

In context

Syphilis

126 studies on the registry are indexed under Syphilis; 34 are open to participants now.

This study's enrollment of 593 is above the median of 354 across 85 interventional studies indexed under Syphilis.

Browse Syphilis studies →

Lead sponsor

National Institute of Allergy and Infectious Diseases (NIAID) is the lead sponsor of 2,446 studies on the registry; 179 are open to participants now.

Of its 405 completed or terminated interventional studies of FDA-regulated products, 302 (75%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 55 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • The subject is 18 to 55 years of age.
  • The subject has signed written .
  • The subject has untreated primary [darkfield or Treponema (T.) pallidum by a rapid, direct, fluorescent antibody darkfield (DFA-TP)] positive genital ulcers, secondary (based on classical palmar/plantar rash, condylomata lata, mucous patches, etc. or darkfield or DFA-TP positive lesions), or early latent syphilis (e.g., current reactive serologic tests for syphilis (STS), and a documented non-reactive STS or documented sexual exposure to a known early latent, primary or secondary syphilis patient in last 12 months; identification of this sexual contact must occur within 60 days of admission into the study).
  • The subject has laboratory evidence of syphilis, i.e., reactive serologic test for syphilis (RPR).
  • The subject is not pregnant, as documented by a negative urine or serum pregnancy test, or lactating.
  • The subject is willing to have an test, and, participate in HIV counseling and return to the clinic for follow-up treatment.

Exclusion criteria

Exclusion Criteria:

  • The subject does not have reactive serologic tests for syphilis.
  • The subject has latent syphilis of unknown duration, late latent syphilis or evidence of neurosyphilis.
  • The subject has a known or suspected allergy to macrolide or azalide antibiotics.
  • The subject has a known or suspected sexually transmitted disease (STD), other than syphilis requiring treatment with a drug, other than azithromycin, active against T. pallidum.
  • The subject has used antibiotics active against T. pallidum in the preceding 30 days. (Note: the use of antimicrobials known to NOT be effective against T. pallidum such as quinolones, sulfonamides, trimethoprim, metronidazole and spectinomycin will be allowed).
  • The subject is known to be positive prior to enrollment.
  • The subject has suspected or known ongoing drug use that might interfere with study participation and follow-up treatment.
  • The subject has a history of cardiovascular disease, known , or known AIDS, which might compromise response to therapy.
  • The subject is judged by the investigators to be unlikely to reliably participate in the study follow-up.
  • The subject has used any drugs in the past 30 days.
  • The subject has any other condition that may impair drug absorption (malabsorption syndrome or active peptic ulcer disease).
Terms in these criteria, in plain language(4)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

HIV

The human immunodeficiency virus, which weakens the immune system.

Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.

Immunosuppression

A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.

Read whether the line is about a condition or about medicines, and which medicines and doses it means.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

05

Study design

Phase
Phase 3
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
593 participants (actual)

Study arms

  • Experimental
    Azithromycin

    Azithromycin 2.0 gram single oral dose.

    Drug: Azithromycin

  • Active comparator
    Benzathine Penicillin

    Benzathine penicillin 2.4 million units administered intramuscularly. Doxycycline will be administered if the patient is allergic to Benzathine Penicillin.

    Drug: Benzathine Penicillin · Drug: Doxycycline

Interventions

  • Single 2 gram oral dose (4 tablets) at Day 1.

  • Supplied in pre-filled syringes containing 1.2 million units of benzathine penicillin; 2.4 million units administered intramuscularly at Day 1, in one or both buttocks.

  • Baseline visit, 28 capsules dispensed, for a dose of 100 mg twice a day (BID).

06

What researchers measure

Primary outcomes

  1. Cure of syphilis defined as a negative reactive serologic test for syphilis (RPR) titer or greater than or equal to a 4-fold (2 dilution) decrease in RPR titer at 6 months following treatment and resolution of all signs and symptoms of syphilis.

    Time frame: Month 6.

Secondary outcomes

  1. Cure rates at 9, 12 and 24 months post treatment and the rate of relapse or reinfection defined as cure followed by recurrent clinical manifestations or a 2-dilution increase in RPR titer over previous lowest result.

    Time frame: Months 9, 12, and 24.

07

Study locations

10 sites
  • University of Alabama Hospital - Infectious Diseases
    Birmingham, Alabama 35249-0001, United States
  • Indiana University
    Indianapolis, Indiana 46202, United States
  • Louisiana State University Health Sciences Center - Infectious Diseases
    New Orleans, Louisiana 70112-2865, United States
  • Johns Hopkins Hospital - Medicine - Infectious Diseases
    Baltimore, Maryland 21287-0005, United States
  • University of North Carolina at Chapel Hill
    Chapel Hill, North Carolina 27514, United States
  • University of North Carolina School of Medicine - Center for Infectious Diseases
    Chapel Hill, North Carolina 27599-7030, United States
  • Durham County Health Department
    Durham, North Carolina 27701-3720, United States
  • Laboratoire National de Reference sur le VIH/SIDA (LNR)
    Analamanga, Antananarivo 101, Madagascar
  • Hopitaly Kely
    Tamatave, Antsiranana, Madagascar
  • Hopitaly Mahabibo
    Mahajanga Majunga, Mahajanga 401, Madagascar
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References and documents

Publications

  • Sena AC, Wolff M, Martin DH, Behets F, Van Damme K, Leone P, Langley C, McNeil L, Hook EW. Predictors of serological cure and Serofast State after treatment in HIV-negative persons with early syphilis. Clin Infect Dis. 2011 Dec;53(11):1092-9. doi: 10.1093/cid/cir671. Epub 2011 Oct 12. PubMed 21998287 ↗
  • Hook EW 3rd, Behets F, Van Damme K, Ravelomanana N, Leone P, Sena AC, Martin D, Langley C, McNeil L, Wolff M. A phase III equivalence trial of azithromycin versus benzathine penicillin for treatment of early syphilis. J Infect Dis. 2010 Jun 1;201(11):1729-35. doi: 10.1086/652239. PubMed 20402591 ↗
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Timeline

Tracking since Sep 25, 2026
Not marked actual or estimatedDates not marked actual or estimated

The record gives a start of Jun 2000, a primary completion of Aug 2007 and a completion of Mar 2009. It does not say whether these dates are actual or estimated.

How these figures are worked out, and which studies are left out of them.

Registered
Mar 6, 2002
First posted
Mar 7, 2002
Start
Jun 2000
Primary completionActual
Aug 2007
CompletionActual
Mar 2009
Last update
Apr 29, 2013
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Apr 29, 2013, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT00031499
Responsible party
Sponsor
First posted
Mar 7, 2002
Start date
Jun 2000
Primary completion
Aug 2007
Completion
Mar 2009
Last update
Apr 29, 2013
View the source record on ClinicalTrials.gov ↗

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This study is completed, as verified in Apr 2013. You cannot join it, but the record below documents what was studied.

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Studies of the drug tested here: Azithromycin

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