Comment from Ruth McCrea

Next-Generation B-Cell Depleters for Long COVID Inebilizumab (anti-CD19), telitacicept (BAFF/APRIL), belimumab (BAFF) | For FDA repurposing / advisory review The opportunity If autoantibodies drive a Long COVID subset, depleting the B-cell lineage that produces them is a validated autoimmune strategy — and several approved agents already do it, each at a different point in the pathway. Three complementary, approved tools Inebilizumab — an anti-CD19 antibody FDA-approved in April 2025 for IgG4-related disease (an 87% flare reduction) and for NMOSD; it reaches CD19+ plasmablasts that anti-CD20 drugs miss [1]. Telitacicept — a TACI-Fc fusion that blocks both B-cell survival factors, BAFF and APRIL; approved for lupus (China, 2021) and in trials across autoimmune disease [2]. Belimumab — an anti-BAFF antibody FDA-approved for SLE and lupus nephritis (and pediatric lupus), restricting mature B-cell survival [3]. The ask A biomarker-gated trial of an approved B-lineage agent in autoantibody-positive Long COVID — graded options from broad depletion (inebilizumab) to survival-factor blockade (telitacicept, belimumab), matched to the humoral mechanism. Sources 1. Inebilizumab (Uplizna, anti-CD19): FDA approval for IgG4-related disease, April 2025 (MITIGATE, 87% flare reduction); also approved for NMOSD. 2. Telitacicept (TACI-Fc, dual BAFF/APRIL): approved in China (2021) for SLE; in trials for additional autoimmune indications. 3. Belimumab (Benlysta, anti-BAFF): FDA-approved for SLE and lupus nephritis; pediatric SLE (2019).