Berahyaluronidase alfa is a recombinant human hyaluronidase that temporarily increases tissue permeability by degrading hyaluronan in the extracellular matrix, thereby facilitating the absorption and dispersion of co-administered subcutaneous drugs like pembrolizumab. Its application significantly enhances the bioavailability of large-molecule biologics via the subcutaneous route, enabling the transition from intravenous to more convenient subcutaneous delivery.