Long Term Safety & Efficacy Study Evaluating The Effect of A4250 in Children With PFIC

Inclusion criteria

• . Completion of the 24-week Treatment Period of Study A4250-005 or withdrawn from Study A4250-005 due to patient/caregiver judgment of intolerable symptoms after completing at least 12 weeks of treatment
• . Signed informed consent and assent as appropriate
• . Patients expected to have a consistent caregiver for the duration of the study
• . Caregivers (and age appropriate patients) must be willing and able to use an eDiary device as required by the study
• . A male or female patient of any age, with a clinical diagnosis of PFIC, including episodic forms (i.e., BRIC), and with a body weight ≥5 kg at Visit S-1.
• . Patient must have clinical genetic confirmation of PFIC
• . Patients with PFIC, excluding BRIC, must have elevated serum bile acid concentration,specifically measured to be ≥100 μmol/L, taken as the average of 2 samples at least 7 days apart (Visits S-1 and S-2) prior to the Screening/Inclusion Visit (Visit 1).
• . Patients with PFIC, excluding BRIC, must have history of significant pruritus and a caregiver-reported observed scratching or patient-reported itching (for patients \>18 with no caregiver-reported observed scratching) in the eDiary average of ≥2 (on 0 to 4 scale) in the 2 weeks prior to the Screening/Inclusion Visit (Visit 1).

Exclusion criteria