Eligible participant will be administered RO0503821 IV using a dose conversion factor of 0.60/150 mcg/kg of the previous weekly ESA dose, (equal to150% assumed equi-effective dose) once weekly up to 19 weeks. After 19 weeks of core treatment period, participants will be followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant will be administered RO0503821 IV using a dose conversion factor of 0.60/150 mcg/kg of the previous weekly ESA dose, (equal to150% assumed equi-effective dose) once in every two weeks up to 19 weeks. After 19 weeks of core treatment period, participants will be followed-up for two optional treatment extension periods (54 weeks each).

An Adverse Events (AEs) is defined as any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. Serious Adverse Events (SAEs) is defined as any untoward medical occurrence that, at any dose, results in death, is life threatening, requires hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, or is a significant medical event in the investigator's judgment or requires intervention to prevent one or other of these outcomes. ). The study design tested 3 different starting dose conversion factors at 3 different dosing schedules during the core study period. As study drug doses can be modified continually over time all results for the two long term safety periods were displayed by dose schedule group only.

Marked abnormality was defined as above and/or below a value which was considered to be potentially clinically relevant. The number of participants with marked lab abnormality across treatment groups were reported and presented. Marked laboratory abnormalities were analyzed according to the Roche specified limits for the following reference range: White blood cells (WBC) (3.0- 18.0 10^9/L), Platelets (100 - 550 10^9/L), Alanine aminotransferase (ALAT) [0 110 units per litre (U/L)], Alkaline Phosphatase (ALP) (0 - 220 U/L), Aspartate aminotransferase (ASAT) (0 - 80 U/L), Albumin >= 30 g/L, Phosphate [0.75 - 1.60 millimoles per liter (mmol/L)], Potassium (2.9 - 5.8 mmol/L), Glucose (2.80 - 11.10 mmol/L).

Mean Change from Baseline in systolic blood pressure (SBP) and diastolic blood pressure (DBP) is calculated as the end of treatment values minus the Baseline value. Baseline (Day -28 to Day 1) values were calculated as the mean of the screening assessment (SA) and run-in period (Week -2 and Week -1).

Participants pulse rates in beats per minute (BpM) were analyzed at sitting position using descriptive statistical methods (ie, means, standard deviations and percentiles). The changes in pulse rate throughout the study were analysed at each study visit and mean change is reported.

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.25/150 mcg/kg of the previous weekly ESA dose, (equal to62.50% assumed equi-effective dose) once in every two weeks up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.40/150 mcg/kg of the previous weekly ESA dose, (equal to100% assumed equi-effective dose) once weekly up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.40/150 mcg/kg of the previous weekly ESA dose, (equal to100% assumed equi-effective dose) once in every two weeks up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.60/150 mcg/kg of the previous weekly ESA dose, (equal to150% assumed equi-effective dose) once weekly up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.60/150 mcg/kg of the previous weekly ESA dose, (equal to150% assumed equi-effective dose) once in every two weeks up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participants were administered intravenously (IV) RO0503821 (methoxy polyethylene glycol-epoetin beta [Mircera]) once weekly (1x/ week) using a dose conversion factor of 0.25/150-, 0.40/150-, and 0.60/150 microgram (mcg)/kilogram (kg) of the previous weekly erythropoiesis stimulating agents (ESA) dose in Cohort 1, Cohort 3, and Cohort 5, respectively for 19 weeks. The ESA dose 62.5%, 100%, and 150% assumed equi-effective dose for dose conversion factors 0.25/150, 0.40/150 and 0.60/150, respectively. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participants were administered IV RO0503821 once every two weeks (1x/ 2week) using a dose conversion factor of 0.25/150, 0.40/150, and 0.60/150 mcg/kg of the previous weekly ESA dose in Cohort 2, Cohort 4, and Cohort 6, respectively for 19 weeks. The ESA dose 62.5%, 100%, and 150% assumed equi-effective dose for dose conversion factors 0.25/150, 0.40/150 and 0.60/150, respectively. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.40/150 mcg/kg of the previous weekly ESA dose, (equal to100% assumed equi-effective dose) once weekly up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.40/150 mcg/kg of the previous weekly ESA dose, (equal to 100% assumed equi-effective dose) once in every two weeks up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.60/150 mcg/kg of the previous weekly ESA dose, (equal to150% assumed equi-effective dose) once weekly up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.60/150 mcg/kg of the previous weekly ESA dose, (equal to150% assumed equi-effective dose) once in every two weeks up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participants were administered IV RO0503821 once every two weeks (1x/ 2week) using a dose conversion factor of 0.25/150, 0.40/150, and 0.60/150 mcg/kg of the previous weekly ESA dose in Cohort 2, Cohort 4, and Cohort 6, respectively for 19 weeks. The ESA dose 62.5%, 100%, and 150% assumed equi-effective dose for dose conversion factors 0.25/150, 0.40/150 and 0.60/150, respectively. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.40/150 mcg/kg of the previous weekly ESA dose, (equal to100% assumed equi-effective dose) once weekly up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.40/150 mcg/kg of the previous weekly ESA dose, (equal to 100% assumed equi-effective dose) once in every two weeks up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.60/150 mcg/kg of the previous weekly ESA dose, (equal to150% assumed equi-effective dose) once weekly up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.60/150 mcg/kg of the previous weekly ESA dose, (equal to150% assumed equi-effective dose) once in every two weeks up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.40/150 mcg/kg of the previous weekly ESA dose, (equal to100% assumed equi-effective dose) once weekly up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.40/150 mcg/kg of the previous weekly ESA dose, (equal to 100% assumed equi-effective dose) once in every two weeks up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.60/150 mcg/kg of the previous weekly ESA dose, (equal to150% assumed equi-effective dose) once weekly up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.60/150 mcg/kg of the previous weekly ESA dose, (equal to150% assumed equi-effective dose) once in every two weeks up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.40/150 mcg/kg of the previous weekly ESA dose, (equal to 100% assumed equi-effective dose) once in every two weeks up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.60/150 mcg/kg of the previous weekly ESA dose, (equal to150% assumed equi-effective dose) once weekly up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).

Eligible participant were administered RO0503821 IV using a dose conversion factor of 0.60/150 mcg/kg of the previous weekly ESA dose, (equal to150% assumed equi-effective dose) once in every two weeks up to 19 weeks. After 19 weeks of core treatment period, participants were followed-up for two optional treatment extension periods (54 weeks each).