A Study of Roxadustat to Treat Anemia in Children and Teenagers With Chronic Kidney Disease

Inclusion Criteria: * Participant has a diagnosis of anemia in CKD Kidney Disease Outcomes Quality Initiative stages 3 or 4 or 5. This can include participants not on dialysis or dialysis dependent (DD) participants (including hemodialysis, peritoneal dialysis and hemodiafiltration participants). * Participants not on dialysis must have an estimated glomerular filtration rate (Schwartz formula) of \< 60 mL/min per 1.73 m\^2. * ESA-treated participants should have a screening Hb level, assessed via HemoCue, between 10.0 and 12.0 g/dL; ESA-naïve participants can have a Hb level ≤ 11 g/dL. * Participant has a ferritin level \> 100 ng/mL or a transferrin saturation (TSAT) value \> 20%. * Participant has an alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2 x upper limit of normal (ULN) and total bilirubin (TBL) ≤ 1.5 x ULN at enrollment visit. * Participant is treated with an ESA or is ESA-naïve, where ESA status is defined as: * ESA-treated: Participant is taking a stable dose of an ESA for at least 4 weeks prior to screening. * ESA-naïve: Participant has no prior ESA exposure OR participant's total prior ESA exposure ≤ 3 weeks within the preceding 4 weeks from screening OR participant was previously treated with and discontinued an ESA ≥ 8 weeks prior to screening. * Female participant is not pregnant and at least 1 of the following conditions apply: * Not a woman of childbearing potential (WOCBP) * WOCBP who agrees to follow the contraceptive guidance from the time of informed consent through at least 4 weeks after final study intervention administration. * Female participant must agree not to breastfeed starting at screening and throughout the study and for 4 weeks post-last roxadustat dose. * Female participant must not donate ova starting at first administration of roxadustat and throughout the study period and for 4 weeks post-last roxadustat dose. * Male participants with female partner(s) of childbearing potential (including breastfeeding partner) must agree to use contraception throughout the treatment period and for 4 weeks post-last roxadustat dose. * Male participants must not donate sperm during the treatment period and for 4 weeks post-last roxadustat dose. * Male participants with pregnant partner(s) must agree to remain abstinent or use a condom for the duration of the pregnancy throughout the study period and for 4 weeks post-last roxadustat dose. * Participant and/or participant's parent or legal guardian agrees for the participant not to participate in another interventional study while participating in the present study. Exclusion Criteria: * Participant has received any investigational therapy within 28 days or 5 half-lives, whichever is longer, prior to screening. * Participant has any medical condition, including active, systemic or clinically significant infection which may pose a safety risk to a participant in this study, which may confound the safety or activity assessment or may interfere with study participation making the participant unsuitable for study. * Participant has a known or suspected hypersensitivity to roxadustat, related hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHI), or any components of the formulation used. * Participant has uncontrolled hypertension (defined as ≥ 95th percentile + 12 mm Hg or ≥ 140/90 mm Hg \[whichever is lower\] for participants \< 13 years of age and ≥ 140/90 mm Hg for participants ≥ 13 years of age measured 3 times at the same visit) in the 2 weeks prior to screening. * Participant has a known hematologic disease other than anemia secondary to renal disease,(e.g., history of sickle cell disease, sickle cell anemia, hemoglobin sickle cell disease, or hemoglobin sickle cell beta thalassemia). * Participant has untreated hypothyroidism. * Participant has severe hyperparathyroidism defined as serum parathyroid hormone (PTH) levels above 1000 pg/mL intact PTH within 4 weeks of screening. * Participant has a functioning kidney allograft. * Participant has a folate or B12 or carnitine deficiency. Acceptable if treated to normal values within 4 weeks of screening. * Participant has a known active malignancy or malignancy within 18 months before the screening visit. Radiation or chemotherapy must be completed at least 12 months before the screening visit. * Participant has a scheduled living donor organ transplantation date within 12 weeks of screening. If participant becomes eligible for a kidney transplant during study conduct, the participant should be discontinued. * Participant has a whole blood or packed red blood cells (pRBC) transfusion during the 8 weeks prior to screening. * Participant has any current condition leading to active significant blood loss in the past 4 weeks. * Participant has a diagnosis of hemolytic uremic syndrome within 12 weeks prior to screening. * Participant who has a previous diagnosis of atypical hemolytic syndrome must be relapse-free (stable hemoglobin (Hb), normal platelet count, normal serum lactate dehydrogenase, and normal haptoglobin level) for more than 12 weeks prior to screening. * Participant has a history of chronic liver disease, including comorbidity with autosomal recessive polycystic kidney disease, cystinosis, and primary hyperoxaluria. * Participant had an episode of peritonitis within 30 days of screening. * Participant has active inflammation such as glomerulonephritis flare (i.e., lupus nephritis, immunoglobulin A (IgA) nephritis, rapidly progressive glomerulonephritis, membranoproliferative glomerulonephritis, antineutrophil cytoplasmic antibodies vasculitis) requiring pulse corticosteroid treatment or induction treatment with an immunosuppressive agent (i.e., cyclophosphamide, rituximab, or another monoclonal antibody) within 6 weeks of screening visit. Receipt of monoclonal antibody or biologic for maintenance treatment of underlying condition is acceptable. * Participant has a known history of human immunodeficiency virus infection. * Participant has rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption or is allergic to peanut or soya.