KK8123 for Hypophosphatemia

Recruiting at 9 trial locations

Overseen By Kyowa Kirin

Age: 18+

Sex: Any

Travel: May Be Covered

Time Reimbursement: Varies

Trial Phase: Phase 1 & 2

Recruiting

Sponsor: Kyowa Kirin, Inc.

Must not be taking: Vitamin D, Oral phosphate

Disqualifiers: Active infection, Uncontrolled hypertension, others

No Placebo Group

Trial Summary

What is the purpose of this trial?

A first-in-human study of KK8123 in adults with X-linked hypophosphatemia.

Do I need to stop my current medications for the KK8123 trial?

You may need to stop certain medications before joining the trial. Specifically, you should not use vitamin D, oral phosphate, certain antacids, and some other medications within 14 days before starting the study. If you are on chronic pain medications, you must keep the same dose and schedule throughout the trial.

What data supports the effectiveness of the drug KK8123 for treating hypophosphatemia?

Research shows that intravenous phosphorus therapy, similar to KK8123, effectively increases phosphorus levels in patients with severe hypophosphatemia, making it a safe and effective treatment option. ^{1 2 3 4 5}

How does the drug KK8123 differ from other treatments for hypophosphatemia?

KK8123 is unique because it is a human monoclonal antibody targeting FGF23, a protein involved in phosphate regulation, which is different from traditional treatments that use phosphate supplements and vitamin D. This approach directly addresses the underlying cause of certain types of hypophosphatemia by reducing the excessive action of FGF23, potentially offering more effective management of the condition. ^{3 6 7 8 9}

Research Team

Kyowa Kirin

Principal Investigator

Kyowa Kirin, Inc.

Eligibility Criteria

Adults aged 18 to 65 with X-linked hypophosphatemia (XLH) can join this trial. They must be on a stable pain medication routine, agree not to change their diet or exercise during the study, and use effective contraception. Pregnant women can't participate, nor those who've had certain treatments for XLH or have medical conditions that might interfere with the study.

Inclusion Criteria

I am on a stable pain medication plan, use effective birth control, and am willing to follow the study's requirements.

I am between 18 and 65 years old and have been diagnosed with XLH.

Agreement not to change diet and exercise regimen during the study

Exclusion Criteria

I haven't taken burosumab, don't plan surgeries soon, and can follow the study plan.

Trial Timeline

Screening

Participants are screened for eligibility to participate in the trial

4 weeks

Dose Escalation

Participants receive varying doses of KK8123 to assess safety, tolerability, PK, and PD

32 to 44 weeks

Observation

Participants are monitored for safety and effectiveness after dose escalation

32 to 44 weeks

Extension

Optional period where participants receive high doses of KK8123 as confirmed for Cohort 3

Treatment Details

Interventions

• KK8123 (Other)

Trial Overview The trial is testing KK8123, a new potential treatment for adults with XLH. This first-in-human study aims to evaluate its safety and how well it works in managing low phosphate levels associated with the condition.

Participant Groups

Group I: Part I: Cohort 4 Experimental Treatment 1 Intervention

Optional, multiple doses of KK8123

Group II: Part I: Cohort 3 Experimental Treatment 1 Intervention

High dose, multiple doses of KK8123

Group III: Part I: Cohort 2 Experimental Treatment 1 Intervention

Mild dose, multiple doses of KK8123

Group IV: Part I: Cohort 1 Experimental Treatment 1 Intervention

Low Dose, single dose of KK8123

Group V: Part 2: Extension Period Experimental Treatment 1 Intervention

High dose, multiple doses as confirmed for Cohort 3 of KK8123.

Who Is Running the Clinical Trial?

Kyowa Kirin, Inc.

Lead Sponsor

Trials

49

Recruited

5,700+

Findings from Research

In a study of 10 adult patients with severe hypophosphatemia, intravenous phosphorus therapy using 9 mmole of monobasic potassium phosphate (KH2PO4) every 12 hours significantly improved serum phosphorus levels, with all patients exceeding 1 mg/dL by 36 hours and six achieving normal levels by 48 hours.

The treatment was found to be safe, as serum potassium levels remained normal and only one patient experienced a decline in serum calcium, indicating that this approach is effective for managing severe hypophosphatemia in patients with normal kidney function.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Efficacy of intravenous phosphorus therapy in the severely hypophosphatemic patient. Vannatta, JB., Whang, R., Papper, S.[2013]

In a study involving 47 critically ill patients with hypophosphatemia, aggressive intravenous administration of potassium phosphate was found to be 98% effective in correcting phosphate levels, regardless of the infusion speed.

The rapid administration of potassium phosphate was deemed safe, with no significant adverse events reported, although one patient experienced a mild increase in serum potassium levels.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intravenous phosphate in the intensive care unit: more aggressive repletion regimens for moderate and severe hypophosphatemia. Charron, T., Bernard, F., Skrobik, Y., et al.[2018]

Severe hypophosphatemia, defined as phosphate levels below 1.0 mg/dl, can occur as a complication of acute pancreatitis, even in cases not related to alcohol abuse, which is a rare finding in the medical literature.

The study highlights the importance of recognizing hypophosphatemia as a potential complication of pancreatic inflammation, as both conditions can significantly impact various physiological systems in the body.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Severe hypophosphatemia associated with gallstone pancreatitis: a case report and review of the literature. Steckman, DA., Marks, JL., Liang, MK.[2021]

Hypophosphatemia is a common issue in ICU patients, particularly those undergoing renal replacement therapies (RRT), which can lead to serious complications like muscle weakness and respiratory failure.

There are currently no specific guidelines for treating hypophosphatemia in critically ill patients, but using phosphate-containing solutions during RRT could help prevent this electrolyte imbalance and its associated risks.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Hypophosphatemia in critically ill patients with acute kidney injury on renal replacement therapies. Pistolesi, V., Zeppilli, L., Fiaccadori, E., et al.[2021]

A revised weight-based phosphorus-dosing algorithm was evaluated in 79 critically ill trauma patients, showing that both moderate and high doses effectively increased serum phosphorus levels, with significant improvements observed by day 2.

The dosing algorithm was found to be safe, as there were no significant changes in serum concentrations of magnesium, sodium, potassium, or ionized calcium during the study, indicating stable metabolic parameters.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A new graduated dosing regimen for phosphorus replacement in patients receiving nutrition support. Brown, KA., Dickerson, RN., Morgan, LM., et al.[2017]

The nationwide survey estimated an annual incidence of 117 cases of FGF23-related hypophosphatemic diseases in Japan, with tumor-induced osteomalacia (TIO) and X-linked hypophosphatemic rickets (XLH) being the most common forms.

While complete tumor resection can improve symptoms in TIO patients, treatments for XLH, such as phosphate and active vitamin D3, do not fully normalize phosphate levels, indicating a need for better management strategies for genetic cases.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Nationwide survey of fibroblast growth factor 23 (FGF23)-related hypophosphatemic diseases in Japan: prevalence, biochemical data and treatment. Endo, I., Fukumoto, S., Ozono, K., et al.[2022]

X-linked hypophosphatemia (XLH) is characterized by renal phosphate wasting and is linked to mutations in the PHEX gene, which affects phosphate regulation and is associated with complications like osteophytes and osteoarthritis.

FGF23 plays a crucial role in XLH by reducing the expression of sodium-phosphate co-transporters in the kidneys, leading to hypophosphatemia despite normal levels of vitamin D, highlighting a novel mechanism of phosphate regulation in the body.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The expanding family of hypophosphatemic syndromes. Carpenter, TO.[2022]

KRN23, a novel anti-FGF23 antibody, effectively increases serum phosphate levels in adults with X-linked hypophosphatemia (XLH) when administered subcutaneously every 28 days, with a significant peak serum phosphate increase observed 7-10 days post-dosing.

The pharmacokinetics of KRN23 show a long elimination half-life of 17.8 days, indicating sustained effects, and the treatment demonstrated a maximum effect on serum phosphate levels, suggesting its potential as a long-term therapy for managing XLH.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Population pharmacokinetic and pharmacodynamic analyses from a 4-month intradose escalation and its subsequent 12-month dose titration studies for a human monoclonal anti-FGF23 antibody (KRN23) in adults with X-linked hypophosphatemia. Zhang, X., Peyret, T., Gosselin, NH., et al.[2021]

This case series highlights three instances of hypophosphataemia (HP) in severely malnourished children, emphasizing its potential severity and association with other electrolyte imbalances, such as hypokalaemia and hypocalcaemia.

The study suggests that HP can complicate conditions like sepsis and pneumonia in malnourished children, indicating the need for careful monitoring and treatment of phosphorus levels to improve outcomes and reduce mortality in this vulnerable population.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Hypophosphataemia among severely-malnourished children: case series. Yoshimatsu, S., Chisti, MJ., Hossain, MI., et al.[2021]

References

1. United States pubmed.ncbi.nlm.nih.gov

Efficacy of intravenous phosphorus therapy in the severely hypophosphatemic patient. [2013]

2. United States pubmed.ncbi.nlm.nih.gov

Intravenous phosphate in the intensive care unit: more aggressive repletion regimens for moderate and severe hypophosphatemia. [2018]

3. United States pubmed.ncbi.nlm.nih.gov

Severe hypophosphatemia associated with gallstone pancreatitis: a case report and review of the literature. [2021]

4. Italy pubmed.ncbi.nlm.nih.gov

Hypophosphatemia in critically ill patients with acute kidney injury on renal replacement therapies. [2021]

5. United States pubmed.ncbi.nlm.nih.gov

A new graduated dosing regimen for phosphorus replacement in patients receiving nutrition support. [2017]

6. Japan pubmed.ncbi.nlm.nih.gov

Nationwide survey of fibroblast growth factor 23 (FGF23)-related hypophosphatemic diseases in Japan: prevalence, biochemical data and treatment. [2022]

7. Japan pubmed.ncbi.nlm.nih.gov

The expanding family of hypophosphatemic syndromes. [2022]

8. England pubmed.ncbi.nlm.nih.gov

Population pharmacokinetic and pharmacodynamic analyses from a 4-month intradose escalation and its subsequent 12-month dose titration studies for a human monoclonal anti-FGF23 antibody (KRN23) in adults with X-linked hypophosphatemia. [2021]

9. Bangladesh pubmed.ncbi.nlm.nih.gov

Hypophosphataemia among severely-malnourished children: case series. [2021]