SCIP III: Clinical evaluation of a single, high dose subcutaneous infusion of benzathine penicillin G (SCIP) for treatment of syphilis
SCIP III: Clinical evaluation of a single, high dose subcutaneous infusion of benzathine penicillin G for treatment of syphilis in adults
The Kids Research Institute Australia
35 participants
Mar 7, 2025
Interventional
Conditions
Summary
Syphilis is an important public health threat in Australia. Benzathine penicillin G (BPG) is the current treatment of choice of non-CNS syphilis infection. Primary, secondary or early latent syphilis is treated with 2.4 million units (MU) of intramuscular BPG injections, while late latent syphilis requires 2.4MU weekly for 3 consecutive weeks. IM BPG injections are associated with significant pain and discomfort for recipients. Consequently, treatment uptake is low, especially where multiple doses are required. Subcutaneous (SC) delivery of BPG is potentially a more efficacious alternative to the current IM injection. Our team has demonstrated acceptability and a superior pharmacokinetic profile in healthy volunteers. Additionally, a small cohort of patients with syphilis reported SC delivery of BPG as a preferred alternative. This study aims to further demonstrate safety and tolerability of a single 7.2MU dose of BPG given as a subcutaneous infusion for the treatment of syphilis. Secondary objectives include demonstrating efficacy of 7.2MU BPG as subcutaneous infusion for the treatment of syphilis and to estimate the proportion of patients with penicillin concentrations above the target concentration of 18mg/mL. Primary outcome is the assessment of safety and tolerability including serious adverse events and reactions. Secondary outcomes are the change in nontreponemal specific serology at 6 months, plasma penicillin concentrations at 6 weeks and the proportion of participants with treatment failure requiring re-treatment at 6 months. We aim to recruit 35 patients with confirmed syphilis infection or contacts of confirmed syphilis infection who would require empirical treatment, at the M Clinic. This study will incorporate self-guided online surveys exploring participant experiences receiving subcutaneous infusion of BPG for syphilis treatment. Participants will be followed up for 24 weeks from day of treatment.
Eligibility
Inclusion Criteria7
- Males and non-pregnant females aged 18 years and older (confirmed by negative HCG test)
- Diagnosis of syphilis infection (made by a clinician) AND requiring treatment with BPG in the form of Bicillin® L-A. This is defined as follows:
- a. Positive treponemal serology (Total antibody AND TPPA)
- b. Primary syphilis (diagnosed clinically) with PCR confirmation of T. pallidum
- Contact of an individual with a diagnosis of syphilis infection, requiring empirical treatment with BPG in the form of Bicillin® L-A.
- Participants who are considered likely to adhere to the trial guidelines for the duration of the trial and are willing and deemed reliable to attend follow up appointments as outlined in the protocol.
- Able to provide informed consent in accordance with Good Clinical Practice.
Exclusion Criteria6
- Pregnant or breastfeeding females.
- Diagnosis of neurosyphilis (CNS, otic or optic syphilis) made by a medical practitioner
- Known hypersensitivity or contraindication to use of penicillin.
- History of anaphylactic reaction to cephalosporin antibiotics.
- Existing dermatological conditions or other abnormalities (e.g., extensive scarring) that may affect skin integrity at the site of injection, especially abdomen or lateral hips.
- Existing circumstances which are likely to impact patient’s participation in the study, as determined by the research clinician. This may include clinical conditions (i.e., surgery), out of study catchment area, not reliably contactable.
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Interventions
7.2MU (13.8mL) of benzathine penicillin G as Bicillin® L-A given as a single subcutaneous infusion (0.5-1mL/min over 10-30minutes) administered by trained clinicians to adults with non-central nervous system syphilis infections. As this is a one-off treatment, monitoring of participant adherence is not required.
Locations(1)
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ACTRN12625000210471