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

Inclusion Criteria:

• 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.

Exclusion Criteria:

• 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-countermedications or supplements for 6 months prior to the screening visit:

1. Compounds with androgenic or estrogenic properties (i.e., agonist orantagonist) or that affect production of sex hormones.

2. 5-α reductase inhibitors, e.g., finasteride and dutasteride.

3. Fertility drugs, including clomiphene, FSH, hMG and hCG preparations.

4. Growth hormone.

5. Opioid-receptor antagonists, e.g., naloxone and long-acting opioids.

6. Selective α-adrenergic-receptor antagonists (alpha blockers).

7. Topical or systemic testosterone replacement therapy (TRT).

8. Anabolic steroids.

• Inability to reliably produce the required semen samples for trial assessments dueto significant erectile dysfunction, anorgasmia, or other reasons.

• Participation in any clinical trial using clinical intervention within 3 monthsbefore the screening visit or 5 half-lives of investigational productadministration, whichever is shorter.

• Any clinically significant 12-lead ECG abnormalities at screening.

• Known history of thromboembolic disease.

• Grade 3 lower extremity edema.

• Known cardiovascular disease.

• Known history of osteoporosis or fragility fractures.

• Known moderate or severe impairment of renal or hepatic function.

• Untreated diagnosis of sleep apnea.

• History of cancer within the last 5 years.

• Known alcohol and/or drug abuse within the last 12 months prior to randomization orevidence of such abuse indicated by the laboratory results during the screeningassessments.

• Known chronic opioid use and/or misuse within the last 12 months prior torandomization.

• Any psychiatric or medical disorder or circumstance, which in the investigator'sopinion might jeopardize participant's safety or compliance with the protocol.

• Hypersensitivity to any active ingredients or excipients in the medicinal productsused in this trial.