A Phase 3 interventional study of Anastrozole and Semaglutide in Klinefelter Syndrome, sponsored by Georgios Papadakis. Recruiting at 1 site in Switzerland. Open to male participants aged 16 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-05-11.
Sponsored by Georgios Papadakis · Phase 3, Interventional, and Treatment
The study seeks primarily to determine whether modulation of systemic and testicular sex steroids balance by aromatase inhibitors will positively affect the metabolic health and spermatogenesis of men with Klinefelter syndrome (KFS) as compared to the current state of the art for each issue.
Secondary objectives of this study are (i) to unravel the heterogeneity of the reproductive and metabolic phenotype of men with KFS by performing a multi-omic analysis in a large cohort at baseline; (ii) to evaluate the efficacy of semaglutide-induced weight loss to achieve metabolic and reproductive benefit in men with Klinefelter syndrome as compared to standard testosterone replacement; (ii) to assess whether addition of hCG to aromatase inhibitors further increases intratesticular testosterone and promotes spermatogenesis in men with KFS.
47 studies on the registry are indexed under Klinefelter Syndrome; 17 are open to participants now.
This study's planned enrollment of 150 is above the median of 44 across 19 interventional studies indexed under Klinefelter Syndrome.
Browse Klinefelter Syndrome studies →This is the only study on the registry with Georgios Papadakis as lead sponsor.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
-Diagnosis of Klinefelter syndrome (47,XXY or mosaicism)
Design 1:
Design 2:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Men with Klinefelter syndrome seeking fertility or interested in fertility preservation that undergo mTESE biopsy after wash-out of testosterone replacement therapy and have positive sperm retrieval (detectable spermatozoids)
Men with Klinefelter syndrome seeking fertility or interested in fertility preservation that undergo mTESE biopsy after wash-out of testosterone replacement therapy and have negative sperm retrieval (no detectable spermatozoids), subsequently randomized to receive an hormonal stimulation for 26 weeks
Drug: Anastrozole
Men with Klinefelter syndrome seeking fertility or interested in fertility preservation that undergo mTESE biopsy after wash-out of testosterone replacement therapy and have negative sperm retrieval (no detectable spermatozoids), subsequently randomized to receive an hormonal stimulation for 26 weeks
Drug: Anastrozole · Drug: human chorionic gonadotropin
Men with Klinefelter syndrome not interested in fertility that present with high metabolic risk and consent to a wash-out of testosterone replacement therapy. They are subsequently randomized to receive an hormonal treatment to improve metabolic health. This arm will receive an active comparator by a testosterone gel
Drug: Testosterone gel
Men with Klinefelter syndrome not interested in fertility that present with high metabolic risk and consent to a wash-out of testosterone replacement therapy. They are subsequently randomized to receive an hormonal treatment to improve metabolic health. This arm will receive an an experimental treatment
Drug: Anastrozole
Men with Klinefelter syndrome not interested in fertility that present with high metabolic risk and consent to a wash-out of testosterone replacement therapy. They are subsequently randomized to receive an hormonal treatment to improve metabolic health. This arm will receive an an experimental treatment
Drug: Semaglutide
This will be an experimental treatment for 26 weeks in Group 1 Arm A and Arm B as well for Group 2 Arm D
Also known as: Anastrozole Teva
This will be an experimental treatment for 26 weeks in Group 2 Arm E
Also known as: Ozempic
This will be an experimental treatment for 26 weeks in addition to anastrozole in Group 1 - Arm B
Also known as: Choriomon
This will be an active comparator for 26 weeks in Group 2 - Arm C
Also known as: Tostran
Design 1 : sperm retrieval rate at mTESE biopsy
Sperm retrieval rate at mTESE biopsy (Group A and B)
Time frame: mTESE biopsy 26 weeks after hormonal intervention
Design 2 : change in insulin resistance index (HOMA-IR)
HOMA-IR calculated using fasting glucose and insulin levels
Time frame: From baseline to week 26 of intervention
Plan to share: Yes — Upon reasonable request and data transfer agreement
Supporting information: Study protocol, Clinical study report
Time frame: At study completion
No publications or documents are linked to this record.
Started Mar 2023 (actual). Primary completion is estimated for Apr 2027, 49 months after the start.
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Studies of the drugs tested here: Anastrozole · Semaglutide · Chorionic Gonadotropin