Recruiting
Phase 2

Tamoxifen

Sponsor:

University Health Network, Toronto

Code:

NCT07535905

Conditions

Hypogonadism

Prostate Cancer

Eligibility Criteria

Sex: Male

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Tamoxifen

Study Details

Brief summary:

Androgen deprivation therapy (ADT) is a cornerstone therapy in the treatment of curable prostate cancer (PCa). However, ADT often leads to a protracted testosterone recovery period in most men or absence of complete recovery in 10-25% of cases. The hypogonadal state has significant psychosocial and physical side effects. Therefore, limiting ADT effect's duration beyond the prescribed castration period is very compelling to patients and providers alike.

Tamoxifen, a well-established selective estrogen receptor modulator, offers a novel and cost-effective approach to accelerate testosterone recovery in men with secondary hypogonadism. This project addresses a critical gap in global cancer care by evaluating Tamoxifen as a viable solution for reducing the burden of delayed testosterone recovery and its associated side effects, particularly in resource-limited settings.

Conditions

Hypogonadism

Prostate Cancer

Study ID

NCT07535905

Start date

Dec 31, 2026

Status verified date

Oct, 2026

Completion date

Oct, 2030

Anticipated

Primary completion date

Oct, 2030

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: Male

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • At least 18 years of age;
  • Ability to understand the purposes and risks of the trial and has signed a written informed consent form. Have a diagnosis of prostate cancer;
  • Patient received ADT for a duration of either 6 or 18-36 months as part of the curative intent treatment. Curative intent prostate cancer patients who completed ADT and have had no further ADT for the length of the last ADT injection depot formulation (e.g., if the last ADT injection depot formulation is for 3 months, the patient must have no ADT for 3 months after last injection)
  • Have effectively castrated testosterone (< 1.7 nmol/L \[50 ng/dL\]) within 6 weeks of enrollment;
  • ECOG Performance status 0-2

Exclusion Criteria:

  • Harbouring certain CYP2D6 alleles (i.e. CYP2D6\*4) or from the chronic use of a CYP2D6 inhibitor(s);
  • History of blood clots (venous thromboembolism or pulmonary embolism);
  • History of stroke or transient ischemic attack (TIA);
  • Reduced liver function within last 120 days prior to enrolment, defined as follows:

1. Total Bilirubin: 1.5 > upper limit of normal (ULN) (For Gilbert's syndrome, if total bilirubin is <1.5 x ULN, measure direct and indirect bilirubin. If direct bilirubin is greater than 1.5 x ULN, participant is ineligible;
2. AST(SGOT) and ALT(SGPT): > 2.5x ULN;
3. Or other liver disease as deemed ineligible by the investigator
  • Baseline QT/QTc > 500ms;
  • Active therapy with selective serotonin reuptake inhibitor (SSRI) antidepressants (e.g. paroxetine, a known CYP2D6 inhibitor);
  • Active therapy with coumarin-type anticoagulants;
  • Active therapy with cytotoxic agents;
  • Active therapy with aromatase inhibitors;
  • Other invasive malignancy within the last 5 years, other than squamous or basal cell carcinoma of the skin;
  • Treatment with a non-approved or experimental drug during the 3 months before informed consent;
  • Patients known to have one of the following hereditary illnesses; galactose- intolerance, Lapp lactase deficiency or glucose-galactose malabsorption;
  • Any other significant concomitant disease or condition that could interfere with the conduct of the study, or that would, in the opinion of the investigator, pose an unacceptable risk to the participant in this trial;

Study Design

Enrollment

96 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

no intervention: Non-Experimental Intervention: Observation

Participant will not receive intervention after treatment with ADT. Per routine care, participant will undergo observation for testosterone recovery

experimental: Experimental Intervention: Tamoxifen

Participant will take 2 tamoxifen pills by mouth, every day, for a total of 40 mg each day. The duration of tamoxifen treatment will depend on the duration of the participant's previous ADT treatment. If the participant received ADT treatment for 6 months, they will receive daily Tamoxifen for 3 months. If the participant received ADT treatment for 18-36 months, they will receive daily Tamoxifen for 6 months.

Interventions

Tamoxifen

Selective estrogen receptor modulator, oral tablet

Primary outcome measure

  • Normal Testosterone Recovery [ Time Frame: 6 months after starting intervention ]

Central Contacts and Locations

Central contacts

Alejandro Berlin, MD

416-946-4501alejandro.berlin@uhn.ca

Locations

University Health Network - Princess Margaret Cancer Center

Recruiting

Toronto, Ontario, Canada, M5G 2M9

Contacts

Alejandro Berlin, MD

416-946-4501alejandro.berlin@uhn.ca

More Information

Sponsor

University Health Network, Toronto

Last update posted

Oct 22, 2026

Last verified

Oct, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-10-23. This information was provided to ClinicalTrials.gov by University Health Network, Toronto on 2026-10-22. Recruitment status is synced daily from ClinicalTrials.gov and may not reflect the sponsor's current status. Confirm during your call.