An Open-Label Study of 50 mg Oral Testosterone Undecanoate (Kyztrex) in Menopausal Women With Low Testosterone and HSDD

San Diego Sexual Medicine (Other)
Overall Status
Not yet recruiting ID

Study Details

Study Description

Brief Summary

This is an unblinded study to be conducted at a single research center, San Diego Sexual Medicine. Eligible subjects will receive 50 mg capsules of Kyzatrax® to be taken orally daily over a 3-month period. Multiple blood samples will be taken at baseline and on days 7, 28 and 56 to assess safety and pharmacokinetics of the testosterone. After the informed consent is signed and for up to 84 days after baseline, subjects will have serial blood samples collected in addition to other routine study procedures (e.g. vital signs measured, adverse events assessed, validated outcome scales completed).

Condition or Disease Intervention/Treatment Phase
  • Drug: Oral Testosterone Undecanoate
Phase 2

Detailed Description

This study is being conducted in an unblinded fashion because the primary endpoint is pharmacokinetic information, and all subjects will receive the same active drug at the same dosage. The primary objectives of this study are to assess the short-term safety and to investigate the pharmacokinetics of serum concentration of total testosterone with daily administration of one (1) 50 mg capsule of testosterone undecanoate (Kyzatrax®) in thirty menopausal women with hypoactive sexual desire disorder (HSDD) and low testosterone. The secondary objective of this study is to assess the efficacy of daily oral administration of one (1) 50 mg capsule of testosterone undecanoate (Kyzatrax®) in thirty menopausal women with HSDD and low testosterone.

The eligibility criterion for testosterone concentration (< 25 ng/mL [< 0.87 nmol/L]) is based on the lower limit of the normal testosterone reference range for adult females. The dose of 50 mg was chosen because this is the lowest oral testosterone currently being manufactured and it represents 12.5% of the starting dose of Kyzatrex FDA approved for men (see Attachment 1). Based on the guidelines of the International Society for the Study of Women's Sexual Health, the starting dose of testosterone for peri- and post-menopausal women is approximately 10% of a testosterone product FDA approved for men. In clinical practice, women are typically prescribed testosterone therapy at 10-20% of the dose given to men, depending on individual adsorption and metabolism characteristics.

Study Design

Study Type:
Anticipated Enrollment :
30 participants
Intervention Model:
Single Group Assignment
Intervention Model Description:
Open label 50mg daily dosing with pharmacokinetics assessed by multiple blood drawsOpen label 50mg daily dosing with pharmacokinetics assessed by multiple blood draws
None (Open Label)
Primary Purpose:
Official Title:
An Open-Label Pilot Study of the Pharmacokinetics and Safety of 50 Mg Oral Testosterone Undecanoate (Kyzatrex) in Menopausal Women With Low Testosterone and Hypoactive Sexual Desire Disorder
Anticipated Study Start Date :
Dec 1, 2023
Anticipated Primary Completion Date :
Jun 1, 2025
Anticipated Study Completion Date :
Dec 1, 2025

Arms and Interventions

Arm Intervention/Treatment
Experimental: Active

Participants will receive 50mg oral testosterone undecanoate daily, have pharmacokinetics assessed and complete validated instruments

Drug: Oral Testosterone Undecanoate
50mg oral testosterone undecanoate daily
Other Names:
  • Kyzatrex
  • Outcome Measures

    Primary Outcome Measures

    1. Testosterone [days 0, 7, 28, 56]

      serum concentration of total testosterone to assess pharmacokinetics

    Secondary Outcome Measures

    1. Female Sexual Function Index [Days 0, 28, 56, 84]

      Female Sexual Function Index to assess changes in each domain and total, total range 2-36, lower the score the more dysfunction therefore worse function

    Eligibility Criteria


    Ages Eligible for Study:
    21 Years to 75 Years
    Sexes Eligible for Study:
    Accepts Healthy Volunteers:
    Inclusion Criteria:
    1. Participant provides written informed consent and HIPAA authorization before any study procedures are conducted;

    2. Participant is female;

    3. Participant is aged 21 years or greater;

    4. Participant is menopausal either naturally (at least 12 months amenorrheic) or after a bilateral salpingo-oophorectomy prior to natural menopause. Subjects with hysterectomy only must meet the following menopause criteria: ≤54 years must be experiencing hot flushes or receiving estrogen therapy for hot flushes (if these subjects are asymptomatic they require a serum FSH > 30 mIU/mL); > 54 years is considered postmenopausal.

    5. Participant is in a monogamous relationship ≥ 6 months;

    6. Participant has a body mass index (BMI) ≤ 35 kg/m2;

    7. Participant has a history of any of the clinical symptoms of low testosterone for at least 6 months prior to the screening visit;

    8. At screening, subject has a calculated free testosterone concentration < 0.6 ng/dL;

    9. Participant agrees to comply with the study procedures and visits.

    Exclusion Criteria:
    1. Participant has a hypersensitivity to testosterone, gelatin, glycerin, sorbitol, and titanium dioxide (the constituents of Kyzatrex capsule);

    2. Participant has received intramuscular testosterone injections, oral or transdermal testosterone within 4 weeks, or subcutaneous testosterone pellet within 6 months prior to the screening visit, or receives any form of testosterone other than study medication during this trial;

    3. Participant has documented or suspected breast cancer, history of heart attack or stroke;

    4. Participant has a clinically significant history of disease which could alter absorption, distribution, metabolism, or elimination, such as hepatic, renal, hematologic, gastrointestinal, respiratory, endocrine, or neurological disease;

    5. Participant has an EKG with an abnormality of clinical significance;

    6. Participant has any chronic medical condition or psychologic disorder that the Principal Investigator feels makes her ineligible for the study;

    7. Participant requires major surgery within 4 weeks before signing consent or at any time during the study;

    8. Participant requires a treatment with any medication listed in Appendix 1 at any time between 30 days before study medication is started or any time until the end of the study;

    9. Participant has a history of substance abuse within 12 months prior to signing consent;

    10. Participant has received an investigational drug within 30 days prior to signing consent;

    11. Participant has any condition or exhibits behavior that indicates to the Principal Investigator that the subject is unlikely to be compliant with study procedures and visits.

    Contacts and Locations


    Site City State Country Postal Code
    1 San Diego Sexual Medicine San Diego California United States 92120

    Sponsors and Collaborators

    • San Diego Sexual Medicine


    • Principal Investigator: Irwin Goldstein, MD, San Diego Sexual Medicine

    Study Documents (Full-Text)

    None provided.

    More Information


    Responsible Party:
    San Diego Sexual Medicine Identifier:
    Other Study ID Numbers:
    • SDSM-2023-03
    First Posted:
    Oct 13, 2023
    Last Update Posted:
    Oct 16, 2023
    Last Verified:
    Oct 1, 2023
    Individual Participant Data (IPD) Sharing Statement:
    Plan to Share IPD:
    Studies a U.S. FDA-regulated Drug Product:
    Studies a U.S. FDA-regulated Device Product:
    Additional relevant MeSH terms:

    Study Results

    No Results Posted as of Oct 16, 2023