CClinicalTrials.gg
Not yet recruitingNCT07640477Updated Jun 10, 2026

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

A Phase 4 interventional study of Zoliflodacin and Placebo in Testicular Abnominalies, sponsored by Global Antibiotics Research and Development Partnership. Not yet recruiting at 2 sites in 2 countries. Open to male participants aged 18 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-06-10.

Sponsored by Global Antibiotics Research and Development Partnership · Phase 4, Interventional, and Screening

Phase
Phase 4
Study type
Interventional
Enrollment
200
Allocation
Randomized
Ages
18 Years to 45 Years
Sex
Male
01

Study summary

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)

02

Conditions studied

  • Testicular Abnominalies

Keywords

  • Testicular toxicities
03

In context

Lead sponsor

Global Antibiotics Research and Development Partnership is the lead sponsor of 3 studies on the registry; 1 is open to participants now.

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

04

Who can participate

Ages eligible
18 Years to 45 Years
Sexes eligible
Male
Accepts healthy volunteers
Yes

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

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 -
05

Study design

Phase
Phase 4
Primary purpose
Screening
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
200 participants (estimated)

Study arms

  • Experimental
    Zoliflodacin

    Drug: Zoliflodacin

  • Placebo comparator
    Placebo

    Drug: Placebo

Interventions

  • DrugZoliflodacin

    Oral suspension of Zoliflodacin 3g

  • DrugPlacebo

    Oral suspension of matching placebo

06

What researchers measure

Primary outcomes

  1. Sperm concentration

    Percentage of participants with a ≥50% decrease from baseline in sperm concentration (million/mL) at Week 13

    Time frame: Week 13 (and potentially week 26)

Secondary outcomes

  1. Semen Volume

    Change in semen volume (in mL)

    Time frame: At baseline and week 13

  2. Sperm count

    Total sperm count per ejaculate (million)

    Time frame: At Baseline and week 13

  3. Progressive mobility

    Sperm exhibiting active forward movement (μm/s)

    Time frame: At Baseline and Week 13

  4. Morphology

    Evaluated using Tygerberg Strict Criteria (%)

    Time frame: At baseline and week 13

  5. Serum Hormones (LH)

    Change in luteinizing hormone (LH), shift analysis relative to reference ranges

    Time frame: At Baseline and Week 13

  6. Serum hormones (FSH)

    Change in Follicle Stimulating Hormone (FSH), shift analysis relative to reference ranges

    Time frame: At Baseline and Week 13

  7. Serum Hormones (Testosterone)

    Change in Testosterone, shift analysis relative to reference ranges

    Time frame: At baseline and week 13

07

Study locations

2 sites
  • Parexel EPCU
    Berlin, Germany
  • Parexel EPCU
    London, United Kingdom
08

References and documents

Individual participant data

Plan to share: Undecided

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jun 10, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT07640477
Lead sponsor
Global Antibiotics Research and Development Partnership
Responsible party
Sponsor
First posted
Jun 10, 2026
Start date
Oct 2026 (estimated)
Primary completion
Nov 2027 (estimated)
Completion
Nov 2027 (estimated)
Last update
Jun 10, 2026

Study contacts

Jovana Albig, MD
Contact
info@gardp.org
+41 22 555 19 90

Oversight

Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is not yet recruiting, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Sign in to follow

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Start the discussion