AKB-6548, reference formulation given in the

Change from pre-dose average was calculated by the mid-study average minus the pre-dose average. The pre-dose average was defined as the average of the 3 Hgb values that were obtained before dosing at the first screening visit, the second screening visit, and the Baseline visit; the mid-study average was defined as the average of the 2 Hgb values that were obtained at the Week 7 and Week 8 visits.

Change from pre-dose average was calculated by the end-of-study average minus the pre-dose average. The pre-dose average was defined as the average of the 3 Hgb values that were obtained before dosing at the first screening visit, the second screening visit, and the Baseline visit; the end-of-study average was defined as the average of the 2 Hgb values that were obtained at the Week 15 and Week 16 visits.

Change from mid-study average was calculated by the end-of-study average minus the mid-study average. The mid-study average was defined as the average of the 2 Hgb values that were obtained at the Week 7 and Week 8 visits; the end-of-study average was defined as the average of the 2 Hgb values that were obtained at the Week 15 and Week 16 visits.

Hemoglobin (Hgb) response was defined as participants with mean Hgb ≥11.0 grams per deciliter (g/dL) (average of Weeks 19 and 20) or increase in Hgb by ≥ 1.2 g/dL (average of Weeks 19 and 20) over pre-dose average (average of the two Hgb values obtained prior to dosing) without receiving Erythropoiesis-Stimulating Agents (ESA) or transfusion.

Absolute change from Baseline was calculated as the Week 6 (end of treatment) value minus the Baseline value. Baseline Hgb was defined as the average of the last two measurements obtained prior to dosing. If there was only one measurement prior to dosing, this measurement served as Baseline. A positive change from Baseline indicated that hemoglobin concentration increased.

Blood samples were collected to assess Hgb. Baseline Hgb was defined as the average of the 2 samples obtained prior to dosing (Pre-Baseline and Baseline). A positive change from baseline indicates that hemoglobin concentration increased.

maximum observed plasma concentration (Cmax) for celecoxib

time to reach Cmax for celecoxib

terminal elimination half-life (t½) for celecoxib

concentration (AUC0-t) for celecoxib

area under the plasma concentration-time curve from 0 to last quantifiable

AUC from time 0 to infinity (AUC0-inf) for celecoxib

apparent oral clearance (CL/F) for celecoxib

apparent volume of distribution during the terminal phase (Vz/F) for celecoxib