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

Part 2: Change from baseline in continuous variables for FSH

Timeframe: For up to 52 weeks.

Part 1: Change from baseline in continuous variables for estradiol

Timeframe: For up to 44 weeks.

Part 2: Change from baseline in continuous variables for estradiol

Timeframe: For up to 52 weeks.

Part 1: Change from baseline in continuous variables for temperature

Timeframe: For up to 44 weeks.

Part 2: Change from baseline in continuous variables for temperature

Timeframe: For up to 52 weeks.

Part 1: Change from baseline in continuous variables for pulse rate

Timeframe: For up to 44 weeks.

Part 2: Change from baseline in continuous variables for pulse rate

Timeframe: For up to 52 weeks.

Part 1: Change from baseline in continuous variables for respiratory rate

Timeframe: For up to 44 weeks.

Part 2: Change from baseline in continuous variables for respiratory rate

Timeframe: For up to 52 weeks.

Part 1: Change from baseline in continuous variables for systolic and diastolic blood pressure

Timeframe: For up to 44 weeks.

Part 2: Change from baseline in continuous variables for systolic and diastolic blood pressure

Timeframe: For up to 52 weeks.

Part 1: Change from baseline in continuous variables for QT

Timeframe: For up to 44 weeks.

Part 2: Change from baseline in continuous variables for QT

Timeframe: For up to 52 weeks.

Part 1: Change from baseline in continuous variables for QTc

Timeframe: For up to 44 weeks.

Part 2: Change from baseline in continuous variables for QTc

Timeframe: For up to 52 weeks.

Part 1: Change from baseline in continuous variables for QTCF

Timeframe: For up to 44 weeks.

Part 2: Change from baseline in continuous variables for QTCF

Timeframe: For up to 52 weeks.

Part 1: Change from baseline in continuous variables for QRS

Timeframe: For up to 44 weeks.

Part 2: Change from baseline in continuous variables for QRS

Timeframe: For up to 52 weeks.

Part 1: Change from baseline in continuous variables for heart rate

Timeframe: For up to 44 weeks.

Part 2: Change from baseline in continuous variables for heart rate

Timeframe: For up to 52 weeks.

Part 1: The presence or absence of abnormality on ectopic mineralization, any sign of left ventricular hypertrophy or heart failures before and after administration of KK8123 on Echocardiogram

Timeframe: For up to 44 weeks.

Part 2: The presence or absence of abnormality on ectopic mineralization, any sign of left ventricular hypertrophy or heart failures before and after administration of KK8123 on Echocardiogram

Timeframe: For up to 52 weeks.

Part 1: Before and after administration presented at each time point in categorical variables for renal ultrasound

Timeframe: For up to 44 weeks.

Part 2: Before and after administration presented at each time point in categorical variables for renal ultrasound

Timeframe: For up to 52 weeks.

Part 1: KK8123 concentrations by maximum plasma concentration (Cmax)

Timeframe: For up to 44 weeks.

Part 2: KK8123 concentrations by maximum plasma concentration (Cmax)

Timeframe: For up to 52 weeks.

Part 1: KK8123 concentrations by maximum serum concentration (tmax)

Timeframe: For up to 44 weeks.

Part 2: KK8123 concentrations by maximum serum concentration (tmax)

Timeframe: For up to 52 weeks.

Part 1: KK8123 concentrations by area under the serum concentration time curve from zero to last detectable time point (AUClast)

Timeframe: For up to 44 weeks.

Part 2: KK8123 concentrations by area under the serum concentration time curve from zero to last detectable time point (AUClast)

Timeframe: For up to 52 weeks.

Part 1: KK8123 concentrations by the area under the serum concentration time curve from zero to infinity (AUC00-inf)

Timeframe: For up to 44 weeks.

Part 2: KK8123 concentrations by the area under the serum concentration time curve from zero to infinity (AUC00-inf)

Timeframe: For up to 52 weeks.

Part 1: KK8123 concentrations by apparent volume of distribution (V/F)

Timeframe: For up to 44 weeks..

Part 2: KK8123 concentrations by apparent volume of distribution (V/F)

Timeframe: For up to 52 weeks.

Part 1: KK8123 concentrations by terminal half-life (t1/2)

Timeframe: For up to 44 weeks.

Part 2: KK8123 concentrations by terminal half-life (t1/2)

Timeframe: For up to 52 weeks.

Part 1: KK8123 concentrations by apparent clearance (CL/F)

Timeframe: For up to 44 weeks.

Part 2: KK8123 concentrations by apparent clearance (CL/F)

Timeframe: For up to 52 weeks.

Part 1: KK8123 concentrations by maximum plasma concentration steady state (Cmax,ss)

Timeframe: For up to 44 weeks.

Part 2: KK8123 concentrations by maximum plasma concentration steady state (Cmax,ss)

Timeframe: For up to 52 weeks.

Part 1: KK8123 concentrations by time to maximum serum concentration steady state (tmax,ss)

Timeframe: For up to 44 weeks.

Part 2: KK8123 concentrations by time to maximum serum concentration steady state (tmax,ss)

Timeframe: For up to 52 weeks.

Part 1: KK8123 concentrations over time by area under the serum concentration curve within a dosing interval at steady state (AUCtau,ss)

Timeframe: For up to 44 weeks.

Part 2: KK8123 concentrations over time by area under the serum concentration curve within a dosing interval at steady state (AUCtau,ss)

Timeframe: For up to 52 weeks.

Part 1: KK8123 concentrations by time to steady state

Timeframe: For up to 44 weeks.

Part 2: KK8123 concentrations by time to steady state

Timeframe: For up to 52 weeks.

Part 1: KK8123 concentrations by accumulation ratio

Timeframe: For up to 44 weeks.

Part 2: KK8123 concentrations by accumulation ratio

Timeframe: For up to 52 weeks.

Part 1: To evaluate the effect of single and multiple SC administrations of KK8123 on serum phosphorus levels

Timeframe: For up to 44 weeks.

Part 2: To evaluate the effect of multiple SC administrations of KK8123 on serum phosphorus levels

Timeframe: For up to 52 weeks.