Actively Recruiting
Open-Label, Multiple-Dose, 52-Week Study and 24-Month Long-Term Safety Extension to Evaluate XYOSTED for Testosterone Replacement in Male Adolescents with Hypogonadism
Led by Halozyme Therapeutics · Updated on 2026-02-18
100
Participants Needed
20
Research Sites
104 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Researchers are evaluating the use of XYOSTED as a testosterone replacement therapy in adolescent males aged 12 to under 18 years with primary or secondary hypogonadism, a condition where the body produces little or no testosterone. This Phase 3/4 open-label study aims to assess how well XYOSTED supports the continuation or start of puberty, along with its safety and the testosterone levels it maintains. Participants will receive XYOSTED injections at doses tailored to their weight and targeted pubertal stage. Dose adjustments will be made based on testosterone levels measured at specific intervals after dosing, with evaluations approximately every three months to reach the desired hormone levels. After completing the 52-week initial study period, participants may enter a 24-month extension to further monitor long-term safety and treatment effects. Throughout the study and extension, participants will undergo clinical examinations including pubertal staging, blood tests for testosterone and other labs, bone density scans, body composition assessments, and X-rays to monitor bone age. Researchers will track changes in puberty progression, bone health, body measurements, and hormone levels. Participants will attend regular clinic visits every six months during the extension phase to continue safety and pharmacokinetic evaluations.
CONDITIONS
Brief Title
52 Week Study + 24-Month Long-Term Extension of Safety, PK, & Efficacy of XYOSTED® for Testosterone Replacement in Male Adolescents With Hypogonadism
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Diagnosed with low or absent testosterone due to primary or secondary hypogonadism with known cause
- Stable testosterone dose for at least 12 weeks before screening or no prior testosterone treatment
- Male aged 12 to under 18 years at consent
- Parent or legal guardian willing to provide written informed consent
- Participant willing to provide assent
- Requires ongoing testosterone treatment to start or continue puberty
- Body mass index above the 5th percentile and weight at least 30 kg
- If sexually active with a female partner who can bear children, agrees to use abstinence or two effective contraceptive methods during and 30 days after treatment
You will not qualify if you...
- Abnormal thyroid function tests at screening
- Suspected or known constitutional delay of growth and puberty
- Nutritional or gastrointestinal disorders affecting growth
- Allergy to XYOSTED or its ingredients including sesame oil
- Unstable testosterone treatment dose or recent changes
- Allergy to foods containing sesame seeds or oil
- Stage 1 hypertension or high blood pressure at screening or day 1
- Significant abnormal lab test results including high hematocrit
- History of blood clots or pulmonary embolism
- Abnormal ECG at screening
- Active or recent pituitary tumors except some stable cysts or microadenomas
- Active cancer or recent cancer treatment within 12 months
- Current use of antipsychotic or SSRI medications
- Other medications or conditions that would affect safety or study evaluation
- History of suicidal behavior or ideation within past year
- Recent use of certain hormone therapies or investigational drugs
- Use of CYP3A4 or P-gp affecting medications within 30 days
- History of alcohol or drug abuse
- Significant kidney, liver, heart, metabolic, neurological, psychiatric, or other conditions precluding participation
- Chronic urticaria or dermatographism
- Vitamin D level below 20 ng/mL without supplementation
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - Up to 28 days
Participants are screened for eligibility to participate in the trial.
1 screening and enrollment visit
Duration - 52 weeks
Participants receive XYOSTED injections with dose adjustments to achieve targeted testosterone levels and Tanner Stage progression.
Visits approximately every 2 to 4 weeks for dose adjustments and evaluations, with additional assessments approximately every 3 months
Duration - 24 months
Participants who continue in the extension study return for clinical, laboratory, and pharmacokinetic evaluations every 6 months to monitor safety and efficacy.
Visits every 6 months
Trial Site Locations
Total: 20 locations
1
Children's Hospital Los Angeles
Los Angeles, California, United States, 90027
Actively Recruiting
2
Rady Children's Hospital - San Diego
San Diego, California, United States, 92123
Actively Recruiting
3
University of California San Francisco
San Francisco, California, United States, 94143
Actively Recruiting
4
Children's Hospital Colorado
Aurora, Colorado, United States, 80045
Actively Recruiting
5
Nemours Children's Specialty Care - Jacksonville
Jacksonville, Florida, United States, 32207
Actively Recruiting
6
Ann & Robert H. Lurie Children's Hospital of Chicago
Chicago, Illinois, United States, 60611
Actively Recruiting
7
Boston Children's Hospital
Boston, Massachusetts, United States, 02115
Actively Recruiting
8
University of Massachusetts Memorial Medical Center
Worcester, Massachusetts, United States, 01655
Actively Recruiting
9
M Health Fairview U Minnesota
Minneapolis, Minnesota, United States, 55454
Actively Recruiting
10
Washington University School of Medicine in St. Louis
St Louis, Missouri, United States, 63110
Actively Recruiting
11
The DOCS
Las Vegas, Nevada, United States, 89113
Actively Recruiting
12
Children's Hospital at Montefiore
The Bronx, New York, United States, 10467
Actively Recruiting
13
OUHSC Pediatric Diabetes & Endocrinology
Oklahoma City, Oklahoma, United States, 73104
Actively Recruiting
14
Children's Hospital of Philadelphia
Philadelphia, Pennsylvania, United States, 19104
Actively Recruiting
15
Prisma Health Children's Hospital - Midlands
Columbia, South Carolina, United States, 29203
Actively Recruiting
16
MedResearch
El Paso, Texas, United States, 79902
Actively Recruiting
17
Texas Children's Hospital
Houston, Texas, United States, 77030
Actively Recruiting
18
Primary Children's Hospital
Salt Lake City, Utah, United States, 84112
Actively Recruiting
19
Seattle Children's Hospital
Seattle, Washington, United States, 98105
Actively Recruiting
20
MultiCare Institute for Research & Innovation
Tacoma, Washington, United States, 98405
Actively Recruiting
Research Team
D
Director Clinical Operations, MPH, CPM
C
Chief Medical Officer, MD, PhD
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
TREATMENT
Number of Arms
1
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