PGT121.414.LS

PGT121.414.LS is a second-generation broadly neutralizing monoclonal antibody (bNAb) engineered for HIV-1 prevention and potential treatment or cure strategies. It is a recombinant human IgG1 antibody that targets a V3 glycan-dependent epitope on the HIV-1 envelope glycoprotein, conferring potent neutralizing activity against diverse HIV-1 strains[1][5]. The ".LS" modification refers to amino acid substitutions in the Fc region designed to extend serum half-life and improve manufacturability and stability compared to its parental form, PGT121[1][3]. In clinical studies, PGT121.414.LS has demonstrated an extended elimination half-life of approximately 66–74 days in humans—about three times longer than unmodified PGT121—and high subcutaneous bioavailability[5][7]. It is being evaluated both as monotherapy and in combination with other bNAbs (such as VRC07-523LS and PGDM1400LS) for safety, pharmacokinetics, tolerability, and antiviral activity in adults without HIV as well as infants exposed to HIV at birth[2][6].