Phase 2 Rare Disease Trial, Recruiting

Written by an AI model from ClinicalTrials.gov eligibility criteria and checked on a sample basis. Please confirm against the original criteria.

Who might be able to join this trial:

Part 1 (First phase of the trial):

• People aged 18 to 65 years old at the time of signing the consent form
• People who weigh at least 40 kg (about 88 pounds)
• People who have been diagnosed with X-linked hypophosphatemia (XLH)
• People whose fasting blood phosphorus level is below a certain threshold at the screening visit (confirm with trial site)
• People whose kidneys are losing phosphorus at a rate below a certain level at screening (confirm with trial site)
• People whose kidneys are functioning well enough, based on a specific blood test result at screening (confirm with trial site)
• People whose blood calcium level is below a certain level at screening (confirm with trial site)
• People who are willing to sign a consent form agreeing to take part
• People who are willing to keep their diet and exercise habits the same from one week before the first dose until the end of the study
• Women who are able to become pregnant must have a negative pregnancy test at screening and agree to further pregnancy tests during the study
• People who take regular pain medications (including strong opioid-based pain relief) must have been on a stable dose for at least 21 days before screening, be willing to stay on that same dose throughout the study, and must not be taking more than the equivalent of 60 mg of oral morphine per day
• People who are sexually active and able to have children must be willing to use contraception during the study and for 5 months after the last dose, in line with local guidelines
• People who, in the investigator's opinion, are willing and able to attend all study visits and complete all required assessments

Part 2 (Second phase of the trial):

• People who completed their relevant group in Part 1 of the study
• People who sign a new consent form after being told about what Part 2 involves
• People who weigh at least 40 kg at the start of Part 2
• Women who are able to become pregnant must have a negative pregnancy test at the start of Part 2 and agree to further pregnancy tests during the study
• People taking regular pain medications (including strong opioid-based pain relief) must have been on a stable dose for at least 21 days before the start of Part 2, be willing to maintain that dose throughout, and must not exceed the equivalent of 60 mg of oral morphine per day
• People who are sexually active and able to have children must be willing to use contraception during the study and for 5 months after the last dose, in line with local guidelines
• People who, in the investigator's opinion, are willing and able to complete all aspects of Part 2, including all visits and assessments

Who may not be able to join:

Part 1:

• People who have previously been treated with burosumab and used it within 7 months before signing the consent form
• People who have previously tested positive for HIV, hepatitis B, or hepatitis C
• People who have had an allergic reaction to any ingredient found in a type of medicine called a monoclonal antibody
• People who currently have an active infection
• People with a significant level of calcium deposits in the kidneys (grade 3 or higher), confirmed by ultrasound
• People with diabetes that is not well controlled at screening
• People with a history of a condition that weakens the immune system
• People with a history of alcohol or drug misuse
• People who have donated blood within 60 days before screening
• People who have taken part in another clinical trial or used an experimental medical device within 30 days before screening, or who will need another experimental treatment before completing this study
• People who have used any therapeutic monoclonal antibody medicine within 90 days before screening
• People who have used certain bone, kidney, or hormone-related medications — including active vitamin D, oral phosphate for XLH, certain antacids, certain water tablets (diuretics), or steroid medicines — within 14 days before screening (a 14-day washout period may apply; confirm with trial site)
• People who have used medicines to suppress a hormone called PTH (such as calcimimetics) within 2 months before screening
• People who have used a medicine called denosumab within 6 months before screening
• People who have used oral bisphosphonate medicines within the 2 years before screening
• People who have used teriparatide or abaloparatide within 2 months before screening
• People whose PTH hormone level in the blood is 2.5 times or more above the upper limit of the normal range at screening (confirm with trial site)
• People who have planned or recommended bone or joint surgery during the study period
• People who have had a bone fracture due to injury or bone/joint surgery within 6 months before screening
• People who are currently breastfeeding
• People who have an active, symptomatic COVID-19 infection at the time of their pre-study assessment
• People who, in the investigator's view, have any condition that raises safety concerns, affects the reliability of study results, or makes it unlikely they will complete the study

Part 2:

• People who used burosumab after completing Part 1
• People who currently have an active infection
• People who donated blood within 60 days before the start of Part 2
• People who used any experimental treatment (other than KK8123, the study drug) or experimental medical device within 30 days before the start of Part 2
• People who used any therapeutic monoclonal antibody medicine (other than KK8123) within 90 days before the start of Part 2
• People who used certain bone, kidney, or hormone-related medications — including active vitamin D, oral phosphate for XLH, certain antacids, certain water tablets (diuretics), or steroid medicines — within 14 days before the start of Part 2
• People who used medicines to suppress PTH (such as calcimimetics) within 2 months before the start of Part 2
• People who used oral bisphosphonate medicines after completing Part 1
• People who used teriparatide or abaloparatide within 2 months before the start of Part 2
• People who have planned or recommended bone or joint surgery during the study period
• People who have had a bone fracture due to injury or bone/joint surgery within 6 months before the start of Part 2
• People who are currently breastfeeding
• People who have an active, symptomatic COVID-19 infection at the start of Part 2, or who have experienced long-term health effects from a previous COVID-19 infection
• People who, in the investigator's view, have any condition that raises concerns about their ability to safely complete the study

Important: Always verify eligibility with the trial site directly before applying.