Elapegademase
Elapegademase is a recombinant form of the enzyme adenosine deaminase (rADA), based on the bovine amino acid sequence and covalently conjugated, with a succinimidyl carbamate linker, to monomethoxypolyethylene glycol (mPEG) (SC-PEG rADA), that can be used as an enzyme replacement agent for the treatment of adenosine deaminase severe combined immune deficiency (ADA-SCID). Upon intramuscular administration, elapegademase, as an exogenous source of ADA, replaces the deficient ADA enzyme and acts in the same manner as the endogenous enzyme. ADA is involved in purine metabolism and mainly catalyzes the irreversible hydrolytic deamination of adenosine or deoxyadenosine to inosine or deoxyinosine, respectively, as well as several naturally occurring methylated adenosine compounds. Elapegademase decreases toxic levels of adenosine and deoxyadenosine nucleotides, increases lymphocyte levels and helps maintain the proper functioning of immune cells. Elevated adenosine levels, as seen in ADA deficiency, induce apoptosis and inhibit the differentiation of thymocytes, resulting in T-lymphopenia. Low levels of deoxyadenosine and adenosine play key roles in the regulation of lymphocyte levels and the proper functioning of immune cells.