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 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. 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.