Infections in secondary immunodeficiency patients treated with Privigen(R) or Hizentra(R): a retrospective US administrative claims study in patients with hematological malignancies

B cell-derived lymphoproliferative disorders are associated with secondary immunodeficiency (SID); some patients require immunoglobulin replacement therapy (IgRT) to mitigate infections. Using IQVIA's PharMetrics(R) Plus database, patients with SID who received IgPro10/IgPro20 in the 12 months post-diagnosis (IgRT users) were matched to patients with SID not receiving IgRT (non-IgRT users). The risk of severe infection was compared using within-patient change from baseline to follow-up as well as between cohorts. Overall, 277 IgRT users were matched to 1019 non-IgRT users. Before IgRT, more IgRT users experienced any bacterial infection (88.4% vs. 72.9%; p<.0001) or >= 1 severe bacterial infection (SBI) (42.2% vs. 31.8%; p=.0011) vs. non-IgRT users. During follow-up, risk of SBI among IgRT users (21.7%) reached parity with non-IgRT users (21.2%). IgRT was associated with a reduction in SBIs to levels comparable with the lower 'baseline infection risk' of non-IgRT users. These criteria help define SID patients who may benefit from IgRT.