Gonorrhea drug zoliflodacin put to the test: will it harm male fertility?
NCT ID NCT07640477
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study will give 200 healthy men a single dose of either zoliflodacin or a placebo to see if the drug affects sperm count, movement, shape, or hormone levels. Participants provide semen and blood samples before and 13 weeks after dosing. If a significant drop in sperm concentration is seen, they will be followed for another 13 weeks to check if the effect reverses.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- zoliflodacin
- What this could lead to
- If this trial shows no harm to testicular function, it would support zoliflodacin as a safe treatment option for gonorrhea without affecting male fertility.
- What could go wrong
- This is a safety study in healthy volunteers, not a treatment trial. It only looks at short-term effects after one dose, so long-term risks remain unknown.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 4
Runs after approval, following long-term safety and how well the treatment works in everyday use.
- Participants
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About 200 people
The number the study aims to enrol. It can still change while the study runs.
- Expected to start
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Oct 2026
An estimate. Start dates often move.
- Expected to finish
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Nov 2027
An estimate. End dates often move.
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 45 years
- Sex
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Male participants only
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
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 -
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As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The study's own enquiry address
This study publishes an address for enquiries. See it below .
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The places running it
2 sites in 2 countries. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
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Contacts and locations
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Genom att skicka in godkänner du våra Användarvillkor
Study contacts
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Contact
Email: •••••@•••••
Locations
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Parexel EPCU
Berlin, Germany
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Parexel EPCU
London, United Kingdom
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