A Novel Aromatase Inhibitor, Leflutrozole, for Treatment of Non-Obstructive Azoospermia
Run by Martin Blomberg Jensen · NCT07571928 · Data updated 2026-11-12
Fully enrolled, still running. This study is not taking new participants. Its registered completion date is 2027-05-31.
This clinical interventional study aims to assess whether treatment with with leflutrozole can improve sperm production in infertile men with non-obstructive azoospermia selected by serum anti-mullerian hormone (AMH) or Inhibin B as a positive predictive biomarker.
Quick facts
| Phase | Phase 1/2 |
|---|---|
| Study type | Interventional |
| Ages | 18 Years to 55 Years |
| Sex | Men only |
| Enrollment | 15 (estimated) |
| Sponsor | Martin Blomberg Jensen Academic / other |
| Drugs / interventions | Leflutrozole, Dose 2 |
| Locations | 1 site (Denmark) |
| Trial ID | NCT07571928 on ClinicalTrials.gov |
What this trial studies
Non-obstructive azoospermia (NOA) is the most severe form of male factor infertility and reflects a profound impairment of spermatogenesis. Men with NOA typically require surgical sperm retrieval procedures, such as testicular sperm aspiration (TESA), testicular sperm extraction (TESE), or micro-TESE, followed by intracytoplasmic sperm injection (ICSI). Even with surgical retrieval, sperm recovery rates remain limited and live birth rates are modest. At present, no pharmacological treatments are approved for male infertility, underscoring a substantial unmet clinical need. Aromatase inhibitors reduce the conversion of testosterone to estradiol by inhibiting the CYP19A1 enzyme, thereby increasing the testosterone-to-estradiol ratio and stimulating gonadotropin secretion. Letrozole and anastrozole have been used off-label in infertile men, including selected patients with NOA, with small studies demonstrating that aromatase inhibition may induce the appearance of spermatozoa in the ejaculate. Leflutrozole is a novel, non-steroidal aromatase inhibitor and a derivative of letrozole with an extended half-life, allowing once-weekly oral dosing at substantially lower doses than conventional daily aromatase inhibitor regimens. Previous clinical studies in men with obesity-associated functional hypogonadism have demonstrated that once-weekly leflutrozole improves serum testosterone concentrations and semen parameters with an acceptable safety profile. The NOVA-NOA trial is a single-…
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Signed informed consent by participant * Signed informed consent by participant's partner (must just be obtained before the par-ticipant starts treatment at Visit 1), if applicable, regarding blood samples, data collec-tion about fertility treatment as well as pregnancy and pregnancy outcome * 18-55 years * Azoospermia verified by at least 2 semen samples, average semen volume \>= 1,0 ml with no identifiable sign of obstruction (samples taken at Visit -1 and at Visit 0 prior to confirmation of eligibility and dosing). * Serum AMH or Inhibin B level above the lower limit of quantification (LLOQ) at screening or within 6 months prior to screening * Testosterone \< 15 nmol/L at screening or within 6 months prior to screening * Serum estradiol above the lower limit of normal range (48 pmol/L) at screening or within 6 months prior to screening Exclusion Criteria: * Klinefelter or other major genetic conditions including large deletions on sex chromosomes * Average testis size \> 20 mL unless obstruction has been excluded * TESE procedure \< ½ year ago * LH concentration \> 15 IU/L at screening * Current abuse of steroids * BMI \> 45 kg/m2 * Severe chronic diseases requiring daily medication * Prior thromboembolic event within the last 24 months * Cardiovascular event within the last 6 months judged as significant by the investigator * Osteoporosis requiring medical treatment * Use of any prescription or non-prescription medication (apart from routine vitamins, occasional use of paracetamol, acetylsalicylic acid, or ibuprofen) which could interfere with pharmacokinetic or pharmacodynamic results, as judged by the investigator, such as: * Herbal products and non-routine vitamins * Insulin * Medication such as systemic corticosteroids, tricyclic antidepressants, and atypical antipsychotics * Surgery scheduled for the trial duration period, except for minor, non-gastrointestinal surgical procedures at the discretion of the investigator * Cancer (past or present, except basal cell skin cancer or squamous cell skin cancer), which in the investigator's opinion could interfere with the results of the trial * Serum prostate specific antigen (PSA) \> 3 ng/mL at screening or within 6 months prior to screening * Hematocrit \>50% at screening or within 6 months prior to screening * Mental incapacity, language barriers or unwillingness to comply with the requirements of the protocol, which may preclude adequate understanding or co-operation during the trial, as judged by the investigator
Where it's running
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Division of Translational Endocrinology, Department of Endocrinology and Internal Medicine, Copenhagen University Hospital Herlev., Herlev,
Herlev, Denmark
Study contacts
- Principal investigator: Martin Blomberg Jensen, D.M.Sc. — Herlev Hospital
How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.