This study is a Single-Center, Single-Arm, open-label, Phase III clinical study to evaluate the efficacy, safety characteristics of Hydroxocobalamin Chloride Injection (20 mg/mL) for Maintenance Therapy in participants with Methylmalonic Acidemia (MMA) with Elevated Homocysteine (Cobalamin C Deficiency).
Age 6 months (inclusive) to < 18 years at the time of first investigational product administration; both sexes eligible.
Documented vitamin B12 responsiveness: ≥ 50 % reduction from pre-treatment baseline in plasma C3/C2 ratio and urinary methylmalonic acid following vitamin B12 therapy.
Presence of pathogenic MMACHC gene variants in a participant with MMA associated with hyperhomocysteinemia.
No emergency room visits or hospitalizations within 6 months prior to screening for metabolic crises (e.g., electrolyte disturbances, metabolic acidosis, dysglycaemia, multi-organ failure); AND
Use of any vitamin B12 preparation other than injectable hydroxocobalamin within 3 months prior to screening.
Participation in another clinical trial within 28 days or 5 half-lives of the investigational agent (whichever is longer) before screening initiation, except for screening-only participants who did not receive study drug.
Prior liver or kidney transplantation, or any prior cell-based therapy.
Hemoglobin < 90 g/L; or