This externally controlled study compared the long-term effects of leniolisib on annual rate of respiratory tract infections and change in serum immunoglobulin M (IgM) levels versus current standard of care, using data from the leniolisib single-arm open-label extension study 2201E1 and the European Society for Immunodeficiencies (ESID) registry. The gene discussed is CD40LG; the disease is Respiratory tract infection.