Abstract
Subcutaneous atezolizumab (with rHuPH20) streamlines anti-PD-L1 delivery while preserving the intravenous (IV) formulation's performance. This review integrates pharmacokinetic, clinical, safety, patient-reported, and operational data from IMscin001 and related studies in NSCLC. A fixed 1,875-mg SC dose every 3 weeks provides bioavailability and steady-state exposure non-inferior to IV, meeting prespecified PK margins and maintaining target engagement. Across phase I-III trials in previously treated patients, objective response, progression-free survival, and overall survival are comparable between routes, with no new safety liabilities. Immune-related adverse events occur at expected rates and grades; the principal route-specific signal is infrequent, mild injection-site reactions. Patient-reported outcomes and preference consistently favor SC dosing due to markedly reduced chair time (~7-minute injection), lower treatment burden, and greater convenience. Time-and-motion analyses indicate meaningful capacity gains, particularly in maintenance settings and resource-constrained clinics. Implementation requires standard immunotoxicity monitoring, nursing competency for large-volume SC administration, and strict route verification. Key gaps include real-world effectiveness and pharmacovigilance at scale, determinants of inter-individual SC bioavailability, optimal injection technique/site, and integration with perioperative or chemotherapy combinations. Overall, SC atezolizumab offers a clinically robust, patient-centered alternative to IV therapy.