A randomized, open-label study on the effect of nipocalimab on vaccine responses in healthy participants

Nipocalimab, a human immunoglobulin G (IgG) 1 monoclonal antibody, selectively binds the IgG-binding site on the neonatal Fc receptor (FcRn) and blocks IgG recycling, reducing IgG levels without impacting antigen presentation or T-/B-cell functions. In this phase 1, open-label study, we assessed the effect of nipocalimab on IgG response in healthy adults receiving T-cell-dependent/-independent vaccines (ie, tetanus toxoid [TT], diphtheria, and acellular pertussis vaccine [Tdap] and 23-polysaccharide pneumococcal vaccine [PPSV®23], respectively). Participants received either no drug (control) or intravenous nipocalimab (30 mg/kg at Week 0; 15 mg/kg at Weeks 2 and 4). All participants received Tdap and PPSV®23 vaccinations on Day 3 and were followed through Week 16. Twenty-nine participants completed the study (active, <i>n</i>=15; control, <i>n</i>=14). All participants mounted a response to Tdap vaccination, with 3 (20%) participants in the active arm and 7 (50%) participants in the control arm achieving a positive anti-TT response at Week 4 (primary endpoint; <i>p</i>=.089). Nipocalimab treatment was associated with numerically lower anti-TT and anti-pneumococcal (PCP)-specific IgG responses at Week 4 but comparable responses at Weeks 2 and 16. Overall, anti-TT IgG levels remained above the protective threshold (0.16 IU/mL) for all participants, and anti-PCP IgG levels remained above the 50 mg/L threshold and showed a 2-fold increase from baseline in both arms. Nipocalimab coadministration with Tdap and PPSV®23 was safe and well tolerated. Results suggest that nipocalimab does not impact the development of IgG responses to T-cell-dependent/-independent vaccines and participants treated with nipocalimab can follow recommended vaccination schedules.<b>Trial registration number</b>: NCT05827874.