A Placebo-controlled Study of Maralixibat (SHP625) in Pediatric Subjects With Progressive Familial Intrahepatic Cholestasis (PFIC)

Key Inclusion Criteria: * Informed consent and assent (as applicable for participants less than or equal to (\<=) 18 years per Institutional Review Board/Ethics Committee (IRB)/Ethics Committee (EC) as appropriate. * Male or female participants between the ages of 12 months and 18 years inclusive (primary cohort) or birth to 18 years inclusive (exploratory cohort) at time of consent, with a body weight greater than or equal to (\>=) 5 kilogram (kg). * Cholestasis as manifested by total sBA greater than (\>) 3\*upper limit of normal (ULN) * An average AM ItchRO(Obs) score \>= 1.5 during the 4 weeks leading to the baseline visit * Diagnosis of PFIC based on: a. Primary cohort: i. Participants with 2 documented mutant alleles in ABCB11 (PFIC2); participants without bile salt export pump (BSEP) function (biallelic truncating mutations in ABCB11) will not be enrolled into the primary cohort. b. Exploratory cohort: i. Participants with PFIC1/3/4 or PFIC2 with biallelic truncating mutationsiii.Infants from birth to \<12 months of age with PFIC ii. Participants with PFIC after internal or external (eg, PEBD) biliary diversion surgery with unsatisfactory pruritus control or where biliary diversion was reversed. Key Exclusion Criteria: * Chronic diarrhea requiring intravenous fluid or nutritional intervention for the diarrhea and/or its sequelae. * History of surgical disruption of the enterohepatic circulation (applies to primary cohort only). * Liver transplant * Decompensated …