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X-linked HypophosphatemiaPhase 3NCT03920072

Study of the Anti-FGF23 Antibody, Burosumab, in Adults With XLH

A Phase 3 study testing Burosumab in people with X-linked Hypophosphatemia, run by Kyowa Kirin Pharmaceutical Development Ltd at 10 sites in 4 countries.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

This is phase 3b open-label, international, multicenter study to continue to monitor the long-term safety and efficacy of burosumab in adult patients with XLH that participated in previous clinical trials with burosumab (UX023-CL303 / UX023-CL304). Read more about this study

Who is it for?
Ages 18 to 70 years
Conditions the study is for
X-linked Hypophosphatemia
What is being tested?
Burosumab
Type of treatment
Injection or infusion
Could I receive a placebo?
No, everyone receives an active treatment
How many people
35 participants
Where
10 sitesin 4 countries
Study dates
7 Mar 2019to 7 Apr 2022
Phase
Phase 3
Are there results?
None posted in the registry

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 18 to 70 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Subjects who provide written informed consent after the nature of the study has been explained, and prior to any research-related procedures.
  • Subjects who participated in Study UX023-CL303 or UX023-CL304. Any subjects that did not complete Study UX023-CL303 or UX023-CL304 may be included on a case-by-case basis. Subjects' enrolment is not dependent on any response to Primary or Secondary endpoints in studies UX023-CL303 or UX023-CL304.
  • Willing to provide access to prior medical records for the collection of historical growth, biochemical and radiographic data, and disease history.
  • Must, in the opinion of the investigator, be willing and able to complete all aspects of the study, adhere to the study visit schedule and comply with the assessments.
  • Females of child-bearing potential must have a negative urine pregnancy test at Screening and be willing to have additional pregnancy tests during the study. Females considered not to be of child-bearing potential include those who have been in menopause for at least two years prior to Screening, or have had tubal ligation at least one year prior to Screening, or have had a total hysterectomy or bilateral salpingo-oophorectomy. If sexually active, male and female subjects must be willing to use one highly effective method of contraception for the duration of the study.

Who cannot join

  • Hypocalcemia or hypercalcemia, defined as serum calcium levels outside the age-adjusted normal limits and deemed as clinically significant in the opinion of the investigator.
  • Presence of a concurrent disease or condition that would interfere with study participation or affect safety in the opinion of the investigator or Sponsor.
  • Use of any investigational product other than burosumab or investigational medical device within 30 days prior to Screening, or requirement for any investigational agent prior to completion of all scheduled study assessments.
  • Subjects with major protocol deviations in Study UX023-CL303 or UX023-CL304 which in the view of the investigator places the subject at high risk of poor treatment compliance or of not completing the study.
  • Subjects who discontinued treatment from Study UX023-CL303 or UX023-CL304 due to either a grade ≥3 treatment-related hypersensitivity reaction or a burosumab-related hypersensitivity reaction reported as a SAE.

Trial locations and contacts

10 sites in 4 countries.

10 sites in 4 countries

United Kingdom5 sites
  • Western General Hospital

    Edinburgh, EH4 2XU

  • National Hospital for Neurology and Neurosurgery-University College London Hospitals NHS Foundation Trust

    London, WC1N 3BG

  • Nuffield Orthopaedic Centre - Oxford University Hospitals Nhs Trust

    Oxford, OX3 7LD

  • Northen General Hospital

    Sheffield, S5 7AU

  • Royal National Orthopaedic Hospital NHS Trust

    Stanmore, HA7 4LP

Other trials in United Kingdom

France3 sites
  • CHU de Bicetre

    Le Kremlin-Bicêtre, 94275

  • Hopital Lariboisiere

    Paris, 75010

  • Hopital Cochin

    Paris, 75014

Other trials in France

Ireland1 site
  • St. Vincent's University Hospital

    Dublin, D04 T6F4

Other trials in Ireland

Italy1 site
  • Azienda ospedaliera universitaria Careggi

    Florence, 50139

Other trials in Italy

About this study

Official title: A Phase 3b Open-label Study of the Anti-FGF23 Antibody, Burosumab (KRN23) in Adult Patients With X-linked Hypophosphatemia (XLH)

This is phase 3b open-label, international, multicenter study to continue to monitor the long-term safety and efficacy of burosumab in adult patients with XLH that participated in previous clinical trials with burosumab (UX023-CL303 / UX023-CL304).

Read the detailed description

XLH is a rare, genetic disorder that is serious, chronically debilitating and represents an unmet medical need. XLH is the most common inherited form of rickets and the most common inherited defect in renal tubular phosphate transport. XLH is transmitted as an X-linked dominant disorder. Mutations resulting in the loss of function of PHEX form the genetic basis for XLH. More than 300 different PHEX gene mutations have been identified in patients with XLH (PHEXdb); however, few definitive correlations have been observed between specific mutations and phenotypic severity.

Patients with XLH have hypophosphatemia due to excessive serum FGF23 levels. FGF23 reduces serum phosphorus levels by two distinct mechanisms of action. The primary mechanism is to inhibit phosphate reabsorption in the proximal tubule of the kidney. The secondary mechanism is to decrease phosphate absorption by the small intestine through the inhibition of 1,25(OH)2D production in the kidney.

Burosumab has the potential to block or reduce FGF23 action and improve phosphate homeostasis in XLH patients. Burosumab binds the amino-terminal domain of FGF23 that interacts with the FGF-binding portion of the combination FGFR1/Klotho receptor, preventing FGF23 from binding to and signaling from its receptor. Both intact and fragmented FGF23 polypeptides are immunoprecipitated with burosumab. By inhibiting FGF23, burosumab restores tubular reabsorption of phosphate (as measured by the ratio of renal tubular maximum reabsorption rate of phosphate to glomerular filtration rate [TmP/GFR]) from the kidney and increases the production of 1,25(OH)2D that also enhances intestinal absorption of phosphate. The dual action on kidney reabsorption and intestinal absorption improves serum phosphorus levels, which is expected to improve bone mineralization and reduce the diverse bone and non-bone manifestations associated with hypophosphatemia in XLH patients.

Being tested
Burosumab
Keywords
Crysvita, Burosumab, X-linked Hypophosphatemia (XLH), PHEX Gene Mutation, PHEXdb
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.

  • BurosumabDrug

    Also called KRN23, Crysvita

    Burosumab is a sterile, clear, colourless and preservative free solution supplied in single-use 5ml vials containing 1mL of burosumab at a concentration of 30mg/mL

Study groups in NCT03920072
Study groupRoleWhat they receive
Open labelOtherAll subjects will be administered subcutaneously burosumab every 4 weeks at the dosage defined in study UX023-CL303 or UX023-CL304 until December 2021 or when the drug becomes commercially available.
Receives: Drug: Burosumab

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Proportion of subjects achieving mean serum phosphorus levels above the LLN (2.5mg/dL[0.81mmol/L]), as averaged across dose cycles between baseline and their last administered dose.

    To establish the effect of burosumab treatment on maintaining serum phosphorus levels to within normal range in adults with XLH.

    Measured: Serum phosphorous levels will be monitored from Screening and every 12 weeks until the end of the study, at approximately 144 weeks.

Secondary outcomes (12)
  1. Effect of burosumab on pre-existing pseudofracture healing will be monitored by centrally read targeted X-Ray

    Targeted radiography at locations pre-determined by the skeletal survey performed during UX023-CL303 or UX023-CL304 will be taken to monitor healing of pseudofractures and/or fractures.

    Measured: Targetted X-Rays at ongoing fracture sites will be taken at the End of Study Visit, approximately week 144.

  2. Effect of burosumab on patients walking ability measured using the 6 Minute Walk Test.

    Patient's motor function by sustained walking will be evaluated using the 6 Minute Walk Test. (6MWT). The percent predicted values for the 6MWT will be calculated using published normative data based on age, gender and height.

    Measured: The 6MWT will be measured at Baseline and then every 12 weeks for the first 48 weeks and then every 24 weeks for up to 144 weeks

  3. Effect of burosumab on Patient mobility assessed using the Timed Up and Go Test (TUG).

    The TUG assesses transitions during ambulatory activity incorporating strength, agility and dynamic balance assessments. The TUG score will be reported as the time (in seconds) that a subject takes to rise from a chair, walk three meters (approximately 10 feet), turn around, walk back to the chair and sit down.

    Measured: The TUG Test will be assessed at Baseline and then every 12 weeks for the first 48 weeks and then every 24 weeks for up to 144 weeks

  4. Effect of burosumab on stiffness and physical function will be assessed using WOMAC.

    The patient's impression of their stiffness and physical function will be assessed by administering the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire- a 24 item patient reported questionnaire. The WOMAC will be administered in a 5-point Likert-scale format using descriptors of none, mild, moderate, severe and extreme corresponding to an ordinal scale of 0 to 4. Higher scores on the WOMAC indicate worse stiffness and functional limitations.

    Measured: The WOMAC questionnaire will be administered at Baseline and then every 12 weeks for 48 weeks and every 12 weeks for up to 48 weeks and then every 24 weeks for up to 96 weeks

  5. Effect of burosumab on patient's pain severity and the impact of pain on functioning will be assessed using the Short-form Brief Pain Inventory questionnaire.

    The patient's recall of pain over a 24 hour period will be captured by administering the short form of the Brief Pain Inventory (BPI) questionnaire. The BPI evaluates the condition of all pain over the previous 24 hours. Two dimensions are measured: pain severity (worst, least, average and now) and the impact of pain on functioning (pain interference with general activity, walking, work, mood, enjoyment of life, relations with others and sleep).

    Measured: The BPI will be administered at Baseline and then every 12 weeks for 48 weeks and then every 24 weeks for up to 144 weeks

  6. Effect of burosumab on patient's fatigue and the interference of fatigue on daily life over a 24 hour period.

    The patient's recall of fatigue will be captured by administering the Brief Fatigue Inventory (BFI) questionnaire. The BFI is a self-reported questionnaire consisting of nine items related to fatigue that are rated on a 0 to 10 numerical rating scale with a recall period of 24 hours. Two dimensions are measured: fatigue and the interference of fatigue on daily life. The change from baseline to post-baseline visits will be assessed.

    Measured: The BFI will be administered at Baseline and then every 12 weeks for up to 48 weeks and then every 12 weeks for up to 144 weeks

  7. Effect of burosumab on bone metabolism and phosphate homeostasis using urinary phosphorus as PD marker.

    Pharmacodynamic assessment.

    Measured: Pharmacodynamic analysis will be conducted at Baseline and every 12 weeks for up to 88 weeks

  8. Effect of burosumab on enthesopathy will be monitored by centrally read targeted X-Ray.

    Lateral foot views (bilateral) will be obtained in all subjects at Screening (as part of skeletal survey) and at End of Study (EOS). Size of enthesopathy spurs at both the superior and inferior calcaneus will be measured in two dimensions.

    Measured: Lateral foot views (bilateral) will be obtained at screening and at End of Study, approximately week 88.

  9. Effect of burosumab on bone metabolism and phosphate homeostasis using Serum Phosphorus as PD marker.

    Pharmacodynamic assessment.

    Measured: Pharmacodynamic analysis will be conducted at Baseline and every 12 weeks for up to 88 weeks.

  10. Effect of burosumab on bone metabolism and phosphate homeostasis using serum 1, 25(OH)2D as PD marker.

    Pharmacodynamic assessment.

    Measured: Pharmacodynamic analysis will be conducted at Baseline and every 12 weeks for up to 88 weeks.

  11. Effect of Burosumab on phosphate reabsorption as measured by the ratio of renal tubular maximum reabsorption rate of phosphate to glomerular filtrate [TmP/GFR].

    Pharmacodynamic assessment.

    Measured: Pharmacodynamic analysis will be conducted at Baseline and every 12 weeks for up to 88 weeks.

  12. Effect of burosumab on health related quality of life as measured by SF-36v2

    Patients will answer questions around their physical functioning, bodily pain, general health perceptions, vitality, social functioning, role limitations due to emotional problems and mental health

    Measured: The SF-36v2 will be administered at Baseline and then every 12 weeks for 48 weeks and then every 24 weeks for up to 144 weeks

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted18 Apr 2019
  2. Study start7 Mar 2019
  3. Primary completion7 Apr 2022
  4. Study completion7 Apr 2022

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Model description
Open-label, international, multicenter
Masking
None (open label)
Enrolment
35 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03920072
Sponsor's protocol ID
BUR02
Status last verified
May 2022
First submitted
29 Oct 2018
Last updated
20 May 2022
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Publications

  • Kamenicky P, Briot K, Brandi ML, Cohen-Solal M, Crowley RK, Keen R, Kolta S, Lachmann RH, Lecoq AL, Ralston SH, Walsh JS, Rylands AJ, Williams A, Sun W, Nixon A, Nixon M, Javaid MK. Benefit of burosumab in adults with X-linked hypophosphataemia (XLH) is maintained with long-term treatment. RMD Open. 2023 Feb;9(1):e002676. doi: 10.1136/rmdopen-2022-002676.

    PubMed 36854566

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing Burosumab in people with X-linked Hypophosphatemia, run by Kyowa Kirin Pharmaceutical Development Ltd at 10 sites in 4 countries.

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 5 inclusion and 5 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: finished, as of the sponsor's last update on 20 May 2022. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 10 sites in United Kingdom, France, Ireland, Italy. 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.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

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?

Proportion of subjects achieving mean serum phosphorus levels above the LLN (2.5mg/dL[0.81mmol/L]), as averaged across dose cycles between baseline and their last administered dose. (time frame: Serum phosphorous levels will be monitored from Screening and every 12 weeks until the end of the study, at approximately 144 weeks.). 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 NCT03920072, which also lists 1 linked publication.

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 20 May 2022.

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