Study to Evaluate the Effect of a Single Oral Dose of Zoliflodacin 3 g on Testicular Function in Healthy Adult Men

A Randomized, Double-blind, Placebo-controlled Study to Evaluate the Effect of a Single Oral Dose of Zoliflodacin 3 g on Testicular Function in Healthy Adult Men

This study is a randomized, double-blind, placebo-controlled clinical trial to evaluate the effect of zoliflodacin on testicular function in healthy adult men. Participants will be screened within 21 days before randomization (Day 1), including collection of 2 semen samples (each collected after a ≥48 hours and ≤7 days ejaculation-free period). Approximately 220 participants who provide written informed consent and meet all inclusion and no exclusion criteria will be enrolled and randomized in a 1:1 fashion to receive a single dose of either zoliflodacin 3 g or placebo administered as an oral suspension on Day 1.

Each participant will be contacted by telephone at Week 1 and at Week 7 post dosing to review adverse events (AEs), concomitant medications and procedures, and genitourinary symptoms.

Each participant will return to the trial site at Week 13 for collection of 2 semen samples (each collected after a ≥48 hours and ≤7 days ejaculation-free period). A serum sample will also be collected for hormone testing (luteinizing hormone [LH], follicle-stimulating hormone [FSH], and total testosterone) at Week 13 to support biological interpretation of any decrease in sperm concentration.

Participants who do not have a ≥50% decrease from baseline in sperm concentration at Week 13 will complete the trial at Week 13 (end of trial). Participants with a ≥50% decrease from baseline in sperm concentration at Week 13 will return to the trial site at Week 26 for collection of 2 semen samples (independent ejaculates, each collected after a ≥48 hours and ≤7 days ejaculation-free period) for evaluation of the reversibility of the Week 13 finding, following completion of a one additional spermatogenic cycle post completion of dosing/drug exposure (FDA 2018) (end of trial).

All Adverse Events, medications, and procedures will be recorded from the signing of the informed consent form (ICF) through the end-of-trial visit (Week 13, Week 26, or Early Termination)

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

200

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Jovana Albig, MD
  • Phone Number: +41 22 555 19 90
  • Email: info@gardp.org

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Man with good general health status, as determined by medical history, physical examination, screening laboratory tests, vital signs (including temperature), and clinical judgment
  2. Age 18 to 45 years at informed consent
  3. Weight ≥35 kg at Screening
  4. Laboratory results at Screening, including FSH, LH, and total testosterone, within laboratory reference ranges
  5. Semen parameters for each semen sample collected during Screening meeting the following criteria (WHO 2021):

    • sperm concentration ≥16 million/mL
    • semen volume ≥1.4 mL
    • total sperm per ejaculate ≥39 million
    • progressive motility ≥ 30%
    • sperm morphology : normal forms ≥4%
  6. Willingness to use a highly effective form of contraception with female sexual partners of reproductive potential for 3 months after the last study drug dose
  7. Provision of written informed consent
  8. Willingness to participate and comply with all aspects of the trial through the entire trial period

Exclusion Criteria:

  1. History of male reproductive health issues including, but not limited to, known hypothalamic-pituitary disorders (e.g., pituitary macroadenomas, pituitary infarction, hyperprolactinemia, panhypopituitarism), primary hypogonadism (e.g., cryptorchidism, Klinefelter's syndrome), Grade III varicocele, testicular torsion, orchitis, unilateral orchiectomy, or prostate gland pathology
  2. Prior diagnosis of male impaired fertility (including reduced fertility)
  3. History of antisperm antibodies
  4. History of radiation to the testicles
  5. History of clinically significant trauma to or surgery on the scrotum or testicles, including vasectomy
  6. Known hypersensitivity to zoliflodacin or formulation excipients
  7. Disorders of sperm transport including, but not limited to, retrograde ejaculation and immotile cilia syndrome
  8. Sexual dysfunction of a nature that would prevent sperm collection in accordance with the protocol requirements (phosphodiesterase inhibitor use is permitted)
  9. Uncontrolled thyroid dysfunction (e.g., untreated hypothyroidism or hyperthyroidism)
  10. Any chronic medical or psychiatric condition that, in the opinion of the investigator, may harm the participant or make the participant unsuitable for the trial or would prevent compliance with the trial protocol procedures
  11. History of major surgery or trauma within 4 weeks before Day 1 or anticipated need for major surgery during the trial
  12. Febrile illness within 4 weeks before Screening
  13. Clinically significant urinary tract infection, prostatitis, epididymitis, or STI diagnosed or treated within 4 weeks before Screening
  14. Genitourinary sign or symptom indicative of a current STI (urethral discharge, dysuria, or genital lesion) at Screening or Day 1
  15. Positive nucleic acid amplification test (NAAT) result for N gonorrhoeae at Screening
  16. Positive serologic test for HIV-1 or HIV-2 antibody, hepatitis B surface antigen, or hepatitis C antibody or for any other pathogen tested according to the trial site standards for blood and semen handling
  17. Use within 13 weeks before Screening of or anticipated need during the trial for a medication known to affect spermatogenesis or reproductive hormone regulation including, but not limited to, the following medications:

    • testosterone
    • gonadotropin analogues
    • anabolic steroids
    • antiandrogens (e.g., spironolactone, finasteride, dutasteride, ketoconazole)
    • 5-α reductase inhibitors
    • α-1 blockers
    • chemotherapeutic agents
    • chronic (≥90 days) use of opioids
    • other hormone-modulating medications
  18. Use within 14 days before Day 1 of a moderate or strong cytochrome P450 isoenzyme 3A4 (CYP3A4) inducer (e.g., rifampin, carbamazepine, phenytoin, St. John's Wort) or anticipated need for moderate or strong CYP3A4 inducers from Day 1 to Day 3
  19. Current tobacco use of ≥1 pack/day or equivalent
  20. Current alcohol use >5 units per week
  21. Known or suspected drug abuse
  22. A positive drug or alcohol screen result at Screening or Day 1 visit
  23. Participation in an interventional clinical study within 30 days or 5 half-lives of the study drug, whichever is longer, before Day 1 -

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Screening
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo
Oral suspension of matching placebo
Experimental: Zoliflodacin
Oral suspension of Zoliflodacin 3g

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Sperm concentration
Time Frame: Week 13 (and potentially week 26)
Percentage of participants with a ≥50% decrease from baseline in sperm concentration (million/mL) at Week 13
Week 13 (and potentially week 26)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Semen Volume
Time Frame: At baseline and week 13
Change in semen volume (in mL)
At baseline and week 13
Sperm count
Time Frame: At Baseline and week 13
Total sperm count per ejaculate (million)
At Baseline and week 13
Progressive mobility
Time Frame: At Baseline and Week 13
Sperm exhibiting active forward movement (μm/s)
At Baseline and Week 13
Morphology
Time Frame: At baseline and week 13
Evaluated using Tygerberg Strict Criteria (%)
At baseline and week 13
Serum Hormones (LH)
Time Frame: At Baseline and Week 13
Change in luteinizing hormone (LH), shift analysis relative to reference ranges
At Baseline and Week 13
Serum hormones (FSH)
Time Frame: At Baseline and Week 13
Change in Follicle Stimulating Hormone (FSH), shift analysis relative to reference ranges
At Baseline and Week 13
Serum Hormones (Testosterone)
Time Frame: At baseline and week 13
Change in Testosterone, shift analysis relative to reference ranges
At baseline and week 13

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

October 1, 2026

Primary Completion (Estimated)

November 1, 2027

Study Completion (Estimated)

November 1, 2027

Study Registration Dates

First Submitted

June 1, 2026

First Submitted That Met QC Criteria

June 5, 2026

First Posted (Actual)

June 10, 2026

Study Record Updates

Last Update Posted (Actual)

June 10, 2026

Last Update Submitted That Met QC Criteria

June 5, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • STI_PMR_Zoli007

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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