X-Linked HypophosphatemiaSUNFLOWERNCT03745521
Study of Longitudinal Observation for Patient With X-linked Hypophosphatemic Rickets/Osteomalacia in Collaboration With Asian Partners
An observational study of X-Linked Hypophosphatemia, run by Kyowa Kirin Co., Ltd. at 1 site in Japan.
Trial summary
Through observation of patients with X-linked hypophosphatemic rickets/osteomalacia (XLH) for up to 10 years, the study intends to collect data that allow achievement of the following objectives: 1. To determine medical characteristics of the disease and the disease process 2. Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- X-Linked Hypophosphatemia
- How many people
- 226 participants
- Where
- 1 siteJapan
- Study dates
- 1 May 2018to 31 Dec 2028
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: Patients with XLH independent of treatment regimen
Who may be able to join
- Patients must meet at least one of the following:
- Documented PHEX gene mutation
- Documented PHEX gene mutation in at least one family member with X-linked genetic relationship
- Documented FGF23 >30 pg/mL
- Typical clinical findings of rickets/osteomalacia
- Written informed consent obtained from patients aged >=18 years or from parents or legally acceptable representatives of patients aged <18 years
Who cannot join
- Participation in any clinical study (trial) at the time of informed consent
- Any patient whose participation in the study is considered inappropriate by the investigator or the subinvestigator
Trial locations and contacts
1 site in 1 country.
About this study
Official title: An International, Multicenter, Prospective, Longitudinal Observational Study for Patient With X-linked Hypophosphatemic Rickets/Osteomalacia
Through observation of patients with X-linked hypophosphatemic rickets/osteomalacia (XLH) for up to 10 years, the study intends to collect data that allow achievement of the following objectives:
- To determine medical characteristics of the disease and the disease process
- To determine physical and psychological burden on patients as well as economic burden
- To assess the efficacy and safety of the treatment of the disease
- Conditions
- X-Linked Hypophosphatemia
- Being tested
- no intervention
- Keywords
- XLH
- Medical subject headings
- Familial Hypophosphatemic Rickets
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
no interventionOther
no intervention
| Study group | Role | What they receive |
|---|---|---|
| X-linked Hypophosphatemia (XLH) | Hypophosphatemic Rickets/osteomalacia Receives: Other: no intervention |
What is being measured
The primary outcome is the main question the study is designed to answer.
Height
Height in centimeters
Measured: After enrollment, patients will be observed annually or every 2 years for up to 10 years.
The 6-Minutes Walking Test
The 6-Minutes Walking Test performed according to International Guidelines, will be measured as distance in meters.
Measured: After enrollment, patients will be observed annually for up to 10 years.
Timed Up and Go Test(TUGT)
The time required for each patient to do the TUGT will be recorded: Stand up from sitting in a chair, walk 3 meters, turn around, walk back, and sit down.
Measured: After enrollment, patients will be observed every 2 years for up to 10 years.
Secondary outcomes (3)
Fracture
Incidence of fracture of all parts
Measured: 10 years
Radiography
Radiography of the sites listed below will be performed. AP views of both knees, PA vies of both wrists, and both long legs. Sites with symptoms such as pain, sites of suspected fracture, and spine (cervical, thoracic and lumber).
Measured: After enrollment, patients will be observed annually or every 2 years for up to 10 years.
Nephrocalcinosis
The renal ultrasound will be performed and the presence and/or progression of nephrocalcinosis will be measured.
Measured: After enrollment, patients will be observed annually or every 2 years for up to 10 years.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Nov 2018
- Study start1 May 2018
- Primary completion31 Dec 2028 (estimated)
- Study completion31 Dec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for X-Linked HypophosphatemiaStudies of the same condition, open and under way.
- More trials run by Kyowa Kirin Co., Ltd.The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 226 participants (actual)
Sponsor and investigators
- Lead sponsor
- Kyowa Kirin Co., Ltd.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03745521
- Sponsor's protocol ID
- SUNFLOWER
- Other IDs
- UMIN000031605
- Acronym
- SUNFLOWER
- Status last verified
- Aug 2025
- First submitted
- 6 Nov 2018
- Last updated
- 5 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Ozono K, Kang HG, Namba N, Ito N, Kubota T, Shintani A, Kawai R, Miyazaki O, Kanematsu M, Ishii H, Michigami T. Burosumab improves alkaline phosphatase and rickets severity in X-linked hypophosphatemia: 3-year SUNFLOWER analysis. Bone Rep. 2026 Aug 30;30:101944. doi: 10.1016/j.bonr.2026.101944. eCollection 2026 Sep.
PubMed 42756680Fukumoto S, Haffner D, Imel EA, Ozono K, Brandi ML, Ishii H, Li Z, Sandilands K, Joos-Vandewalle P, Lee C, Kanematsu M, McCullough KP, Carpenter TO. Real-world impact of treatment on growth in children with X-linked hypophosphatemia. J Clin Endocrinol Metab. 2026 Aug 13;111(9):2513-2524. doi: 10.1210/clinem/dgag136.
PubMed 41911946Carpenter TO, Fukumoto S, Haffner D, Imel EA, Ozono K, Ishii H, Li Z, Sandilands K, Joos-Vandewalle P, Lee C, Kanematsu M, McCullough KP, Brandi ML. Advancing Patient Evidence in XLH (APEX): Baseline analysis of a global data unification program. Bone. 2025 Dec;201:117649. doi: 10.1016/j.bone.2025.117649. Epub 2025 Sep 15.
PubMed 40962182Ito N, Kang HG, Michigami T, Namba N, Kubota T, Shintani A, Kawai R, Kabata D, Ishii H, Nishida Y, Fukumoto S, Ozono K. Prevalence of Comorbid Hyperparathyroidism and Its Association with Renal Dysfunction in Asian Patients with X-Linked Hypophosphatemic Rickets/Osteomalacia. Calcif Tissue Int. 2025 Mar 12;116(1):50. doi: 10.1007/s00223-025-01359-9.
PubMed 40074938Kubota T, Fukumoto S, Cheong HI, Michigami T, Namba N, Ito N, Tokunaga S, Gibbs Y, Ozono K. Long-term outcomes for Asian patients with X-linked hypophosphataemia: rationale and design of the SUNFLOWER longitudinal, observational cohort study. BMJ Open. 2020 Jun 29;10(6):e036367. doi: 10.1136/bmjopen-2019-036367.
PubMed 32601114
Study at a glance
From the registry record, last updated by the sponsor on 5 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An International, Multicenter, Prospective, Longitudinal Observational Study for Patient With X-linked Hypophosphatemic Rickets/Osteomalacia
- ClinicalTrials.gov ID
- NCT03745521
- Acronym / sponsor ID
- SUNFLOWER / SUNFLOWER
- Conditions
- X-Linked Hypophosphatemia
- Keywords
- XLH
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 226 participants (actual)
- Lead sponsor
- Kyowa Kirin Co., Ltd.Industry (pharma, biotech, devices)
- Study start
- 1 May 2018 (actual)
- Primary completion
- 31 Dec 2028 (estimated)
- Study completion
- 31 Dec 2028 (estimated)
- First posted
- 19 Nov 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Through observation of patients with X-linked hypophosphatemic rickets/osteomalacia (XLH) for up to 10 years, the study intends to collect data that allow achievement of the following objectives:
- To determine medical characteristics of the disease and the disease process
- To determine physical and psychological burden on patients as well as economic burden
- To assess the efficacy and safety of the treatment of the disease
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| X-linked Hypophosphatemia (XLH) | – | Other: no interventionHypophosphatemic Rickets/osteomalacia |
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Patients with XLH independent of treatment regimen
Key inclusion criteria (6 listed)
- Patients must meet at least one of the following:
- Typical clinical findings of rickets/osteomalacia
- Written informed consent obtained from patients aged >=18 years or from parents or legally acceptable representatives of patients aged <18 years
Key exclusion criteria (2 listed)
- Participation in any clinical study (trial) at the time of informed consent
- Any patient whose participation in the study is considered inappropriate by the investigator or the subinvestigator
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| no interventionno intervention | Other | X-linked Hypophosphatemia (XLH) |
Primary outcome
Height
Time frame: After enrollment, patients will be observed annually or every 2 years for up to 10 years.
Height in centimeters
The 6-Minutes Walking Test
Time frame: After enrollment, patients will be observed annually for up to 10 years.
The 6-Minutes Walking Test performed according to International Guidelines, will be measured as distance in meters.
Timed Up and Go Test(TUGT)
Time frame: After enrollment, patients will be observed every 2 years for up to 10 years.
The time required for each patient to do the TUGT will be recorded: Stand up from sitting in a chair, walk 3 meters, turn around, walk back, and sit down.
3 secondary outcomes
Fracture
Time frame: 10 years
Radiography
Time frame: After enrollment, patients will be observed annually or every 2 years for up to 10 years.
Nephrocalcinosis
Time frame: After enrollment, patients will be observed annually or every 2 years for up to 10 years.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Sep 2025.
- Derived from this study: PubMed 42756680Ozono K, Kang HG, Namba N, Ito N, Kubota T, Shintani A, Kawai R, Miyazaki O, Kanematsu M, Ishii H, Michigami T. Burosumab improves alkaline phosphatase and rickets severity in X-linked hypophosphatemia: 3-year SUNFLOWER analysis. Bone Rep. 2026 Aug 30;30:101944. doi: 10.1016/j.bonr.2026.101944. eCollection 2026 Sep.
- Derived from this study: PubMed 41911946Fukumoto S, Haffner D, Imel EA, Ozono K, Brandi ML, Ishii H, Li Z, Sandilands K, Joos-Vandewalle P, Lee C, Kanematsu M, McCullough KP, Carpenter TO. Real-world impact of treatment on growth in children with X-linked hypophosphatemia. J Clin Endocrinol Metab. 2026 Aug 13;111(9):2513-2524. doi: 10.1210/clinem/dgag136.
- Derived from this study: PubMed 40962182Carpenter TO, Fukumoto S, Haffner D, Imel EA, Ozono K, Ishii H, Li Z, Sandilands K, Joos-Vandewalle P, Lee C, Kanematsu M, McCullough KP, Brandi ML. Advancing Patient Evidence in XLH (APEX): Baseline analysis of a global data unification program. Bone. 2025 Dec;201:117649. doi: 10.1016/j.bone.2025.117649. Epub 2025 Sep 15.
- Derived from this study: PubMed 40074938Ito N, Kang HG, Michigami T, Namba N, Kubota T, Shintani A, Kawai R, Kabata D, Ishii H, Nishida Y, Fukumoto S, Ozono K. Prevalence of Comorbid Hyperparathyroidism and Its Association with Renal Dysfunction in Asian Patients with X-Linked Hypophosphatemic Rickets/Osteomalacia. Calcif Tissue Int. 2025 Mar 12;116(1):50. doi: 10.1007/s00223-025-01359-9.
- Derived from this study: PubMed 32601114Kubota T, Fukumoto S, Cheong HI, Michigami T, Namba N, Ito N, Tokunaga S, Gibbs Y, Ozono K. Long-term outcomes for Asian patients with X-linked hypophosphataemia: rationale and design of the SUNFLOWER longitudinal, observational cohort study. BMJ Open. 2020 Jun 29;10(6):e036367. doi: 10.1136/bmjopen-2019-036367.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of X-Linked Hypophosphatemia, run by Kyowa Kirin Co., Ltd. at 1 site in Japan.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 5 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Japan. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Height (time frame: After enrollment, patients will be observed annually or every 2 years for up to 10 years.). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03745521, which also lists 5 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Sep 2025.