What is KK8123 studying for X-linked hypophosphatemia?

KK8123 is being studied to assess its safety, how it behaves in the body, and its effects in adults with X-linked hypophosphatemia. This trial aims to better understand this drug's potential impact on the condition. The study is sponsored by Kyowa Kirin Co., Ltd. and includes dose escalation and safety evaluation phases.

Who may be eligible for this X-linked hypophosphatemia clinical trial?

Adults aged 18 to 65 years with a confirmed diagnosis of X-linked hypophosphatemia may be eligible. Participants must weigh at least 40 kg and have certain lab values within specific ranges. People with active infections or recent use of certain medications may be excluded. Please review eligibility criteria for more details.

Is there any cost to participate in this X-linked hypophosphatemia clinical trial?

Study-related care, including the study drug and all trial visits, is provided at no cost. Personal travel expenses may vary and are not guaranteed to be covered. Participants should plan accordingly for any travel or accommodation costs.

Actively Recruiting

Phase 1

Phase 2

Age: 18Years - 65Years

All Genders

ID06525636

Phase 12 Multicenter Study of Subcutaneous KK8123 Treatment in Adults Aged 18 to 65 With X-linked Hypophosphatemia

Led by Kyowa Kirin Co., Ltd. · Updated on 2025-11-14

Participants Needed

Research Sites

12 weeks

Total Duration

AI-Summary

What this Trial Is About

Researchers are evaluating the safety, tolerability, pharmacokinetics PK, and pharmacodynamics PD of KK8123 in adults with X-linked hypophosphatemia XLH through a Phase 12, multicenter, open-label, dose-escalation study. This first-in-human study aims to better understand how KK8123 behaves in the body and its effects on patients with this condition. The study is sponsored by Kyowa Kirin Co., Ltd. and includes an optional safety extension period. The study includes a Screening Period of up to 28 days, followed by Part 1, which is a Dose Escalation Period consisting of a planned Treatment Period and an Observation Period lasting 32 to 44 weeks. Part 2 is an optional Extension Period for additional safety evaluation. Participants receive subcutaneous doses of KK8123 at different levels, including low dose single dose, mild dose multiple doses, and high dose multiple doses, with dosing confirmed for later cohorts. The study groups include several cohorts receiving escalating doses and an extension group. Participants will undergo multiple assessments during the study, including laboratory tests for hematology and clinical chemistry, measurement of serum phosphorus levels, echocardiograms, renal ultrasounds, and monitoring of vital signs such as heart rate and blood pressure. Researchers will track treatment-emergent adverse events TEAEs and measure KK8123 drug concentrations over time. Follow-up periods last up to 44 weeks in Part 1 and up to 52 weeks in Part 2. Participants are expected to adhere to study visit schedules and complete all assessments throughout their involvement.

CONDITIONS

Brief Title

A First-in-human Study of KK8123 in Adults With X-linked Hypophosphatemia

Who Can Participate

Age: 18Years - 65Years

All Genders

Eligibility Criteria

You may qualify if you...

Male or female patients aged 18 to 65 years inclusive at the time of signing the informed consent form.
Body weight of at least 40 kg.
Diagnosed with X-linked hypophosphatemia (XLH) as documented by the investigator.
Fasting serum phosphorus level less than 2.5 mg/dL (0.81 mmol/L) at screening.
Renal TmP/GFR less than 2.5 mg/dL (0.81 mmol/L) at screening.
Estimated glomerular filtration rate (eGFR) of 60 mL/min or higher at screening.
Corrected serum calcium level less than 10.8 mg/dL (2.7 mmol/L) at screening.
Provide signed informed consent.
Agree not to change diet and exercise regimen from one week prior to dosing to end of study.
Negative pregnancy test at screening and willingness to have additional pregnancy tests during the study (female participants only).
If taking chronic pain medications, stable regimen for at least 21 days before screening and willingness to maintain stable dose during the study (dose not exceeding 60 mg oral morphine equivalents/day).
Willingness to use contraception during the study and for 5 months after last dose if sexually active and of childbearing potential.
Willing and able to complete all study aspects, adhere to visits, and comply with assessments as judged by investigator.

You will not qualify if you...

Use of burosumab within 7 months prior to informed consent.
Positive test history for HIV antibody, hepatitis B surface antigen, or hepatitis C antibody at screening.
History of hypersensitivity to any therapeutic monoclonal antibody ingredient.
Active infection.
Grade 3 or greater nephrocalcinosis confirmed by renal ultrasound.
Uncontrolled diabetes mellitus at screening.
History of known immunodeficiency.
History of alcoholism or drug abuse.
Blood donation within 60 days prior to screening.
Use of investigational products or devices within 30 days prior to screening.
Use of therapeutic monoclonal antibodies within 90 days prior to screening.
Use of certain medications including pharmacologically active vitamin D, oral phosphate, aluminum hydroxide antacids, acetazolamide, thiazide diuretics, systemic corticosteroids within 14 days prior to screening.
Use of medication to suppress parathyroid hormone within 2 months prior to screening.
Use of denosumab within 6 months prior to screening.
Use of oral bisphosphonates within 2 years prior to screening.
Use of teriparatide or abaloparatide within 2 months prior to screening.
Plasma intact parathyroid hormone ≥ 2.5 times upper limit of normal at screening.
Planned or recommended orthopedic surgery during the study.
Traumatic fracture or orthopedic surgery within 6 months prior to screening.
Lactating participants.
Current active and symptomatic COVID-19 infection at Day -1.
Any condition that may increase risk of poor treatment compliance or study completion as judged by investigator.

Research Team

Kyowa Kirin

Not the Right Trial for You?

Explore thousands of other clinical trials that might be a better match.
Sign up to get personalized trial recommendations delivered to your inbox.

Already have an account? Log in here

Phase 12 Multicenter Study of Subcutaneous KK8123 Treatment in Adults Aged 18 to 65 With X-linked Hypophosphatemia

On this page

AI-Summary

What this Trial Is About

Brief Title

Who Can Participate

Eligibility Criteria

Research Team

Not the Right Trial for You?

On this page

Who Can Participate

Eligibility Criteria