Phase 4 Comparative Trial of Benzathine Penicillin G for Treatment of Early Syphilis in Subjects With or Without HIV Infection

A Phase 4 Comparative Trial of Benzathine Penicillin G 2.4 Million Units Administered as a Single Dose Versus Three Successive Weekly Doses for Treatment of Early Syphilis in Subjects With or Without HIV Infection

This is a phase 4, randomized, open-label, multicenter trial to evaluate the efficacy of a single injected dose of Benzathine Penicillin G (BPG) 2.4 MU (Arm 1) compared to three successive weekly injected doses of BPG 2.4 MU (Arm 2) for treatment of early syphilis in human immunodeficiency virus (HIV)-infected and HIV-uninfected subjects. The study will enroll 560 adults (to achieve 420 evaluable subjects) aged 18 years or older with untreated early syphilis (primary, secondary, or early latent). It will be conducted at 9 sites in the US and last for 48 months with patient participation duration of 12 months. The primary objective is to compare the serological response to therapy in subjects with early (primary, secondary, or early latent) syphilis treated with Benzathine Penicillin G (BPG) 2.4 million units (MU) once or weekly for three successive weeks.

Study Overview

• Status: Completed
• Conditions: Syphilis
• Intervention / Treatment: Drug: Benzathine Penicillin

Detailed Description

This is a phase 4, randomized, open-label, multicenter trial to evaluate the efficacy of a single injected dose of Benzathine Penicillin G (BPG) 2.4 MU (Arm 1) compared to three successive weekly injected doses of BPG 2.4 MU (Arm 2) for treatment of early syphilis in human immunodeficiency virus (HIV)-infected and HIV-uninfected subjects. The study will enroll 560 adults (to achieve 420 evaluable subjects) aged 18 years or older with untreated early syphilis (primary, secondary, or early latent). It will be conducted at 9 sites in the US and last for 48 months with patient participation duration of 12 months. The primary objective is to compare the serological response to therapy in subjects with early (primary, secondary, or early latent) syphilis treated with Benzathine Penicillin G (BPG) 2.4 million units (MU) once or weekly for three successive weeks. The secondary objectives are: 1) to determine if the difference in response to therapy between treatment arms by Month 6 differs among subjects with or without HIV infection; 2) to determine the impact of multiple BPG injected doses on subject compliance with study product and adherence to the corresponding scheduled visits; 3) to determine the incidence and manifestations of the Jarisch-Herxheimer reaction among subjects treated for early syphilis with BPG; 4) to collect prospective data up to Month 12 on the serological response to therapy in subjects treated for early syphilis with either BPG regimen; 5) to compare epidemiological characteristics of early syphilis among subjects with or without HIV infection.

• Study Type: Interventional
• Enrollment (Actual): 249
• Phase: Phase 4

Contacts and Locations

Study Locations

• United States
  • Alabama
    • Birmingham, Alabama, United States, 35294
      • University of Alabama at Birmingham School of Medicine - Infectious Disease
  • Georgia
    • Atlanta, Georgia, United States, 30308
      • Emory University Hospital Midtown - Emory Clinic Infectious Diseases
  • Indiana
    • Indianapolis, Indiana, United States, 46202
      • Indiana University School of Medicine - Infectious Diseases
  • Louisiana
    • New Orleans, Louisiana, United States, 70119
      • Louisiana State University Health Sciences Center
  • Maryland
    • Baltimore, Maryland, United States, 21224
      • Johns Hopkins Bayview Medical Center - Infectious Diseases
  • Massachusetts
    • Boston, Massachusetts, United States, 02115
      • Fenway Health - The Fenway Institute
  • North Carolina
    • Durham, North Carolina, United States, 27701-3720
      • University of North Carolina School of Medicine - Center for Infectious Diseases
    • Winston-Salem, North Carolina, United States, 27157
      • Wake Forest Baptist Health - Infectious Diseases
  • Pennsylvania
    • Pittsburgh, Pennsylvania, United States, 15213
      • Magee Women's Hospital of UPMC - Reproductive Infectious Disease Research
  • Washington
    • Seattle, Washington, United States, 98104-2433
      • University of Washington - Harborview Medical Center - Center for AIDS and STD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 99 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Subject is aged 18 years or older.
2. Subject has provided informed consent.

3. Subject has untreated primary*, secondary**, or early latent*** syphilis.

   *Primary syphilis is characterized by the presence of an ulcerative lesion at a potential site of inoculation (while classically solitary, shallow, painless and with an indurated, clean base, primary lesions may be multiple, may vary considerably in appearance, and/or may not be painless) or by darkfield, acceptable polymerase chain reaction (PCR), or direct fluorescence antibody-T. pallidum (DFA-TP) positive ulcers.

   **Secondary syphilis is characterized by classical palmar/plantar rash, condylomata lata, mucous patches, etc. or by darkfield, acceptable PCR, or DFA-TP positive lesions.

   ***Early latent syphilis is characterized by current reactive serologic tests for syphilis (STS) and a documented non-reactive STS, or documented sexual exposure to an individual known to have primary, secondary, or early latent syphilis diagnosed within the last 12 months.

4. Subject either has a newly reactive non-treponemal test (such as an RPR test) or a history of syphilis and a current increase in RPR titer of two or more dilutions (i.e., four-fold).
5. If subject is of childbearing potential, subject has a negative urine or serum pregnancy test.
6. Subject is willing to have an human immunodeficiency virus (HIV) test, participate in HIV counseling, and return to clinic for follow-up.
7. In the opinion of the investigator, subject is able and willing to comply with study procedures, including receipt of three Benzathine Penicillin G (BPG) injected doses if randomized to Arm 2.

8. If female, subject must be of non-childbearing potential* or must be using an acceptable method of birth control** to avoid becoming pregnant.

   • Non-childbearing potential is defined as being post-menopausal for at least 1 year, status after bilateral tubal ligation, or status after bilateral oophorectomy, or status after hysterectomy.

     • Subject must agree to avoid becoming pregnant by using one of the following acceptable methods of birth control for the entire duration of participation in the trial:

       • Intrauterine contraceptive device; OR
       • Oral contraceptives; OR
       • Hormonal injections; OR
       • Hormonal implants; OR
       • Contraceptive patches; OR
       • Monogamous relationship with vasectomized partner; OR
       • Exclusively same-sex relationships; OR
       • Use of condoms by the male partner; OR
       • Abstinence

Exclusion Criteria:

1. Subject previously enrolled in this trial.

2. Subject has latent syphilis of unknown duration, late latent syphilis, or evidence of neurosyphilis, including ocular syphilis.*

   *e.g., eye pain/redness, recent ocular change, and/or changes in visual acuity

3. Subject has a known or suspected allergy or hypersensitivity to penicillin or other beta-lactam antibiotics.
4. Subject has a known or suspected sexually transmitted infection (STI) other than syphilis requiring treatment with a drug active against T. pallidum.

5. 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 (e.g., quinolones, sulfonamides, trimethoprim, metronidazole, spectinomycin) will be allowed.

6. Subject has suspected or known ongoing drug use that might interfere with study participation and follow-up treatment.
7. Subject is breastfeeding.

8. Subject has used an investigational drug in the past 30 days that might interfere with safety or efficacy assessment.

   *If the subject has used any investigational drugs in the past 30 days, contact the Principal Investigator, Division of Microbiology and Infectious Diseases (DMID) Clinical Project Manager, DMID Medical Officer, and FHI 360 to confirm eligibility.

9. Subject has any other condition that, in the opinion of the investigator, would interfere with participation in the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: 1; 2.4 million units (MU) of Benzathine penicillin G (BPG) intramuscularly on Day 1, n=280	Drug: Benzathine Penicillin; BPG will be administered as a deep intramuscular injection in the upper, outer quadrant of the buttock.
Experimental: 2; 2.4 million units (MU) of Benzathine penicillin G (BPG) intramuscularly weekly for three successive weeks, n=280	Drug: Benzathine Penicillin; BPG will be administered as a deep intramuscular injection in the upper, outer quadrant of the buttock.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The Number of Participants With a Serological Response by Month 6.	Serological response to therapy by Month 6 was defined as follows, where available rapid plasma reagin (RPR) results from all visits prior to the end of the Month 6 visit window (i.e., scheduled visits up to and including the Month 6 visit, early termination visit, or any unscheduled visit that occurred prior to the end of month 6 visit window) were evaluated: 4-fold or greater decline in RPR titer at any visit prior to the end of the Month 6 visit window compared to baseline, OR; RPR-negative at any visit prior to the end of the Month 6 visit window (i.e., seroreversion).	Day 1 to Day 180

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Categorical Descriptive Statistics of Sexual History at Baseline Collected Via a Study-specific Questionnaire	Gender identity, sexual orientation, sexual partner, sex history in last 60 days	Day 1
Continuous Descriptive Statistics of Sexual History at Baseline Collected Via a Study-specific Questionnaire	Sex history in last 60 days	Day 1
Categorical Descriptive Statistics of Socio-epidemiologic Characteristics at Baseline Collected Via a Study-specific Questionnaire	Highest level of education completed, stage of syphilis, prior syphilis history	Day 1
Continuous Descriptive Statistics of Socio-epidemiologic Characterictics at Baseline Collected Via a Study-specific Questionnaire	Years of formal education	Day 1
Categorical Descriptive Statistics of Participant Baseline Demographics Collected Via a Study-specific Questionnaire	Sex, Ethnicity, Race	Day 1
Continuous Descriptive Statistics of Participant Baseline Demographics Collected Via a Study-specific Questionnaire	Age	Day 1
The Number of Participants Who Receive All Assigned Doses Within the Assigned Visit Windows	Compliance with study product will be defined as the participant received all assigned doses within the assigned visit windows. A participant is not adherent to study product if they miss at least one dose or receive at least one dose out of the visit window.	Through Month 12
The Number of Participants Who Report Jarisch-Herxheimer Reaction Manifestations	Approximately 24 hours after Visit 1, participants were contacted and evaluated for symptoms of a JHR, which included fever, chills, myalgia, weakness, flushing, worsening of skin rash, tachycardia, heart palpitations, arthralgia, nausea, headache, and dizziness, including time of onset and time of resolution of each symptom reported.	Day 1 through Day 2
Number of Participants With Serological Response by Month 6 Among Participants With or Without HIV Infection	Serological response to therapy by Month 6 was defined as follows, where available rapid plasma reagin (RPR) results from all visits prior to the end of the Month 6 visit window (i.e., scheduled visits up to and including the Month 6 visit, early termination visit, or any unscheduled visit that occurred prior to the end of month 6 visit window) were evaluated: 4-fold or greater decline in RPR titer at any visit prior to the end of the Month 6 visit window compared to baseline, OR; RPR-negative at any visit prior to the end of the Month 6 visit window (i.e., seroreversion). Serological response to therapy by Month 6 was examined among participants with and without HIV infection,	Day 1 to Day 180
Number of Participants With Serological Response (Defined as Either a 4-fold or Greater Decline in Rapid Plasma Regain (RPR) Titer Compared to Baseline or Being Rapid Plasma Regain -Negative [Seroreversion]) by Month 12.	Serological response to therapy by Month 12 was defined as follows, where available rapid plasma reagin (RPR) results from all visits prior to the end of the Month 12 visit window (i.e., scheduled visits up to and including the Month 12 visit, early termination visit, or any unscheduled visit that occurred prior to the end of month 12 visit window) were evaluated: 4-fold or greater decline in RPR titer at any visit prior to the end of the Month 12 visit window compared to baseline, OR; RPR-negative at any visit prior to the end of the Month 12 visit window (i.e., seroreversion).	Through month 12
Number of Participants With Serological Response by Month 12 Among Subjects With or Without HIV Infection	Serological response to therapy by Month 12 was defined as follows, where available rapid plasma reagin (RPR) results from all visits prior to the end of the Month 12 visit window (i.e., scheduled visits up to and including the Month 12 visit, early termination visit, or any unscheduled visit that occurred prior to the end of month 6 visit window) were evaluated: 4-fold or greater decline in RPR titer at any visit prior to the end of the Month 12 visit window compared to baseline, OR; RPR-negative at any visit prior to the end of the Month 12visit window (i.e., seroreversion). Serological response to therapy by Month 12 was examined among participants with and without HIV infection,	Through month 12
Categorical Descriptive Statistics of Sexual History at Week 1 Collected Via a Study-specific Questionnaire	Sex history since last visit.	Through week 1
Categorical Descriptive Statistics of Sexual History at Week 2 Collected Via a Study-specific Questionnaire	Sex history since last visit.	Through week 2
Categorical Descriptive Statistics of Sexual History at Month 1 Collected Via a Study-specific Questionnaire	Sex history since last visit.	Through month 1
Categorical Descriptive Statistics of Sexual History at Month 3 Collected Via a Study-specific Questionnaire	Sex history since last visit.	Through month 3
Categorical Descriptive Statistics of Sexual History at Month 6 Collected Via a Study-specific Questionnaire	Sex history since last visit.	Through month 6
Categorical Descriptive Statistics of Sexual History at Month 9 Collected Via a Study-specific Questionnaire	Sex history since last visit.	Through month 9
Categorical Descriptive Statistics of Sexual History at Month 12 Collected Via a Study-specific Questionnaire	Sex history since last visit.	Through month 12
Continuous Descriptive Statistics of Sexual History at Week 1 Collected Via a Study-specific Questionnaire	Sex history since last visit	Through week 1
Continuous Descriptive Statistics of Sexual History at Week 2 Collected Via a Study-specific Questionnaire	Sex history since last visit	Through week 2
Continuous Descriptive Statistics of Sexual History at Month 1 Collected Via a Study-specific Questionnaire	Sex history since last visit	Through month 1
Continuous Descriptive Statistics of Sexual History at Month 3 Collected Via a Study-specific Questionnaire	Sex history since last visit	Through month 3
Continuous Descriptive Statistics of Sexual History at Month 6 Collected Via a Study-specific Questionnaire	Sex history since last visit	Through month 6
Continuous Descriptive Statistics of Sexual History at Month 9 Collected Via a Study-specific Questionnaire	Sex history since last visit	Through month 9
Continuous Descriptive Statistics of Sexual History at Month 12 Collected Via a Study-specific Questionnaire	Sex history since last visit	Through month 12

Collaborators and Investigators

• Sponsor: National Institute of Allergy and Infectious Diseases (NIAID)

Publications and helpful links

General Publications

• Dionne-Odom J, Workowski K, Perlowski C, Taylor SN, Mayer KH, McNeil CJ, Hamill MM, Dombrowski JC, Batteiger TA, Sena AC, Wiesenfeld HC, Newman L, Hook EW 3rd. Coinfection With Chlamydial and Gonorrheal Infection Among US Adults With Early Syphilis. Sex Transm Dis. 2022 Aug 1;49(8):e87-e89. doi: 10.1097/OLQ.0000000000001605. Epub 2022 Jan 24.

Study record dates

Study Major Dates

• Study Start (Actual): October 31, 2018
• Primary Completion (Actual): September 7, 2022
• Study Completion (Actual): March 20, 2023

Study Registration Dates

• First Submitted: August 16, 2018
• First Submitted That Met QC Criteria: August 16, 2018
• First Posted (Actual): August 20, 2018

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: December 19, 2024
• Last Verified: September 19, 2019

More Information

Terms related to this study

• Keywords: HIV; Phase 4; Benzathine penicillin G; Early Syphillis
• Additional Relevant MeSH Terms: Blood-Borne Infections; Urogenital Diseases; Genital Diseases; Immune System Diseases; Infections; RNA Virus Infections; Virus Diseases; Communicable Diseases; Sexually Transmitted Diseases, Viral; Sexually Transmitted Diseases; Lentivirus Infections; Retroviridae Infections; Immunologic Deficiency Syndromes; Bacterial Infections; Bacterial Infections and Mycoses; Gram-Negative Bacterial Infections; Spirochaetales Infections; Sexually Transmitted Diseases, Bacterial; Treponemal Infections; HIV Infections; Syphilis; Anti-Bacterial Agents; Anti-Infective Agents; Penicillins; Penicillin G; Penicillin G Benzathine; Penicillin G Procaine
• Other Study ID Numbers: 17-0101

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No