TZLS-501, a unique and best-in-class anti-IL-6R mAb, follows a dual mechanism by not only blocking downstream signaling pathways from membrane-bound and soluble IL-6 receptors, but it also rapidly depletes blood-stream levels of IL-6, the major culprit for cytokine release syndrome (CRS) in lungs of COVID-19 patients. In receptor binding assays, TZLS-501 is considerably more potent than the other anti-IL-6R mAb in this class, such as Actemra (Roche). These biochemical features, differentiating TZLS-501 from other mAbs in this class, offer potential distinctive clinical advantages in effecting a rapid suppression of the cytokine storm at much lower doses.