Changes in Intravenous Immunoglobulin Usage for Hypogammaglobulinemia After Implementation of a Stewardship Program

Intravenous immunoglobulin (IVIG) is used to replenish immunoglobulins in hypogammaglobulinemia (HG) caused by hematologic malignancies (HM) or their treatment (autologous stem-cell transplantation [ASCT] and chimeric antigen receptor T-cell therapy [CAR-T]), in an effort to reduce the risk of infections. However, there is limited evidence to support this use, and IVIG supplies are limited and shortages are common.

An IVIG stewardship program (ISP) was implemented with the following requirements for IVIG administration: immunoglobulin G (IgG) level < 400 mg/dL (corrected for paraprotein) for post-ASCT and post-CAR-T patients, or IgG < 400 mg/dL with a history of a bacterial infection within the preceding 3 months for those with HM. Comparisons of the amount of IVIG administered, the incidence of infections, and the use of antimicrobials were performed between the 3 months before ISP and the 3 months after ISP.

IVIG administered for HG decreased from 4,902 g in 86 patients before ISP to 1,777 g in 55 patients after ISP, a cost savings of $44,700. Adherence to ISP guidelines was 80%. Compared with before ISP, patients who stopped receiving IVIG after ISP had lower nadir IgG, fewer infections/patient-months, less antimicrobial usage, and a lower hospitalization rate for infection; no deaths occurred. Compared with before ISP, patients receiving IVIG after ISP had lower predose IgG and fewer infections/patient-months; the antibiotic usage, hospitalization rate for infection, and deaths from infection remained stable.

To our knowledge, this is the first ISP to lead to a dramatic decrease in IVIG usage with high adherence, primarily by selecting out patients at low risk of infection after IVIG discontinuation. Such an ISP is replicable and warrants adoption.