Long-Term Immune Reconstitution in ADA-Deficient Patients Treated With Elapegademase: A Real-World Experience

ADAGEN, a bovine-based enzyme replacement therapy (ERT), has been used to treat adenosine deaminase severe combined immunodeficiency (ADA-SCID). In 2018, ADAGEN was replaced by REVCOVI (elapegademase), a modified bovine recombinant protein.

To determine the real-life long-term benefits of REVCOVI in ADA-SCID.

Data on ERT, infectious and noninfectious complications, and metabolic and immune evaluations were collected from 17 patients with ADA-SCID treated for 6 months or more with REVCOVI.

Eleven patients had previously received ADAGEN for 16 to 324 months, whereas 6 patients were ERT-naive. REVCOVI was administered twice weekly at 0.4 mg/kg/wk in ERT-naive patients, whereas patients transitioning to REVCOVI from ADAGEN typically continued at the same frequency and equivalent dosing as ADAGEN, resulting in a significantly lower (P = .007) total REVCOVI dose in the transitioning group. REVCOVI treatment in the ERT-naive group led to the resolution of many clinical and laboratory complications of ADA deficiency, whereas there were no new adverse effects among the transitioning patients. REVCOVI treatment increased plasma ADA activity and decreased dAXP (which included deoxyadenosine mono-, di-, and tri phosphate) among most patients, effects that persisted throughout the 7- to 37-month treatment periods, except in 2 patients with incomplete adherence. Among some patients, after 0.5 to 6 months, injection frequency was reduced to once a week, while maintaining adequate metabolic profiles. All ERT-naive infants treated with REVCOVI demonstrated an increase in the number of CD4⁺ T and CD19⁺ B cells, although these counts remained stable but lower than normal in most transitioning patients.

REVCOVI is effective for the management of ADA-SCID.