A Clinical Trial Evaluating the Efficacy and Safety of Leflutrozole on Testicular Function

NCT06993155 | Recruiting Phase 2 FDA Drug

• 1 other identifier: RPN-LFT01
• Study Type: interventional
• Target: 200
• Locations: 1 country
• Sites: 4

Brief Summary

The goal of this clinical trial is to evaluate three doses of the drug leflutrozole on improvement of semen quality in men. It will also study the safety of leflutrozole. The main questions it aims to answer are:

• Does leflutrozole improve semen quality?
• What medical problems do participants experience when taking leflutrozole? Researchers will compare leflutrozole to a placebo (a look-alike substance that contains no drug). Participants will:
• Take leflutrozole or a placebo orally once a week for 16 weeks.
• Visit the clinic every 4 weeks for checkups and tests.
• Provide semen samples to measure changes in semen quality.
• Have their blood tested to measure hormone levels and ensure safety.
• Be monitored for any side effects.

Conditions

Semen Quality

Outcome Measures

Primary Outcomes (1)

• Change in total motile sperm count (TMSC) after 16 weeks of treatment.

  Total motile sperm count will be assessed through semen analysis conducted at specialized andrology laboratories.

  From baseline to the end of treatment at 16 weeks.

Secondary Outcomes (21)

• Changes in total sperm count (TSC), sperm concentration, sperm motility, normal sperm morphology, and semen volume after 16 weeks of treatment.

  From baseline to the end of treatment at 16 weeks.

• Percentage of participants with TMSC ≥5 million, ≥10 million, and ≥20 million after 16 weeks of treatment.

  At end of treatment at 16 weeks.

• Percentage of participants with a relative increase of ≥50%, ≥75% and ≥100% in TMSC after 16 weeks of treatment.

  From baseline to the end of treatment at 16 weeks.

• Percentage of participants with sperm DNA fragmentation index (DFI) <15%, <25% and <30% after 16 weeks of treatment.

  At end of treatment at 16 weeks.

• Percentage of participants with serum total testosterone levels within the range of 450-1000 ng/dL after 4, 8, 12 and 16 weeks of treatment.

  At 4 , 8, 12 and 16 weeks of treatment.

Study Arms (4)

Leflutrozole, 0.05 mg

EXPERIMENTAL

Leflutrozole, 0.05 mg, oral capsule, once weekly for 16 weeks

Drug: Leflutrozole, Dose 1

Leflutrozole, 0.1 mg

EXPERIMENTAL

Leflutrozole, 0.1 mg, oral capsule, once weekly for 16 weeks

Drug: Leflutrozole, Dose 2

Leflutrozole, 0.3 mg

EXPERIMENTAL

Leflutrozole, 0.3 mg, oral capsule, once weekly for 16 weeks

Drug: Leflutrozole, Dose 3

Placebo

PLACEBO COMPARATOR

Placebo, oral capsule, once weekly for 16 weeks

Drug: Placebo

Interventions

Leflutrozole, Dose 1 DRUG

Leflutrozole, Dose 1 once weekly for 16 weeks

Leflutrozole, 0.05 mg

Leflutrozole, Dose 2 DRUG

Leflutrozole, Dose 2 once weekly for 16 weeks

Leflutrozole, 0.1 mg

Leflutrozole, Dose 3 DRUG

Leflutrozole, Dose 3 once weekly for 16 weeks

Leflutrozole, 0.3 mg

Placebo DRUG

Placebo once weekly for 16 weeks

Placebo

Eligibility Criteria

• Age: 18 Years - 49 Years
• Sex: male
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Signed informed consent form prior to any-related trial activity.
• Adult men aged 18-49 years (both inclusive).
• Low serum total testosterone concentration on two occasions.
• Serum estradiol (E2) level within or above normal range at screening.
• Serum Luteinizing Hormone level within or below normal range at screening.
• Low total motile sperm count in two samples.
• Semen volume ≥1.0 mL in two samples.
• Ability to understand and comply with the requirements of the protocol.

You may not qualify if:

• Anatomical abnormalities of the testes or malignant or benign tumors of the testes.
• Pituitary or hypothalamic disease.
• Prostate disease.
• Treatment with one or more of the following prescription drugs or over-the-counter medications or supplements for 6 months prior to the screening visit:
• Compounds with androgenic or estrogenic properties (i.e., agonist or antagonist) or that affect production of sex hormones.
• α reductase inhibitors, e.g., finasteride and dutasteride.
• Fertility drugs, including clomiphene, FSH, hMG and hCG preparations.
• Growth hormone.
• Opioid-receptor antagonists, e.g., naloxone and long-acting opioids.
• Selective α-adrenergic-receptor antagonists (alpha blockers).
• Topical or systemic testosterone replacement therapy (TRT).
• Anabolic steroids.
• Inability to reliably produce the required semen samples for trial assessments due to significant erectile dysfunction, anorgasmia, or other reasons.
• Participation in any clinical trial using clinical intervention within 3 months before the screening visit or 5 half-lives of investigational product administration, whichever is shorter.
• Any clinically significant 12-lead ECG abnormalities at screening.

Sponsors & Collaborators

• ReproNovo Aps: lead

Study Sites (4)

ReproNovo Investigational Site

North Hollywood, California, 91606, United States

RECRUITING

ReproNovo Investigational Site

Pomona, California, 91767, United States

RECRUITING

ReproNovo Investigational Site

Garden City, New York, 11530, United States

RECRUITING

ReproNovo Investigational Site

Middleburg Heights, Ohio, 44130, United States

RECRUITING

MeSH Terms

Interventions

leflutrozole

Study Officials

• Medical Director

  ReproNovo Aps

  STUDY DIRECTOR

Central Study Contacts

Public Disclosure

CONTACT

+45 32225466; publicdisclosure@repronovo.com

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 19, 2025
• First Posted: May 28, 2025
• Study Start: June 27, 2025
• Primary Completion (Estimated): July 1, 2026
• Study Completion (Estimated): November 1, 2026
• Last Updated: February 27, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

US (4)