https://orcid.org/0000-0001-5263-1283
Key Points
The likelihood of infections/severe infections and associated antimicrobial use decreased after IgRT initiation.
Among patients with accessible SPEP tests, IgRT use was associated with significant reductions in hypogammaglobulinemia.
This study assessed the real-world effectiveness of immunoglobulin replacement therapy (IgRT) for treatment of hypogammaglobulinemia and infections in patients with multiple myeloma (MM). A retrospective study was conducted in adult patients diagnosed with MM on or after January 1, 2010 using the Mass General Brigham Research Patient Data Registry. Infections were compared before versus after IgRT initiation. Generalized estimating equation logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). In patients with accessible serum protein electrophoresis (SPEP) tests, a natural language processing program supported the extraction of immunoglobulin G (IgG) data. IgG assessments and determination of hypogammaglobulinemia (defined as IgG level <500 mg/dL) were compared before versus after IgRT initiation. Results were reported with descriptive statistics. 6,062 patients with MM were identified (56.2% men, median age 65.0 years). 471/6,062 (7.8%) received ≥1 IgRT administrations. At 3 months, significantly lower odds of infections (OR [95% CI]: 0.71 [0.56, 0.89], P=0.0004) were observed after IgRT initiation versus before. Among patients with accessible SPEP tests (n=3,405), 3231 (94.9%) received ≥1 IgG test, with a median of 18.0 (interquartile range [IQR]: 7.0, 40.0) IgG tests per patient. Hypogammaglobulinemia was experienced by 2,075/3,231 (64.2%) patients who had ≥1 IgG test. Significantly fewer patients had hypogammaglobulinemia after IgRT initiation. In conclusion, IgRT use was associated with significant reductions in hypogammaglobulinemia and infections. While IgRT is currently used for MM treatment, there is potential to optimize its dosing and treatment duration to reduce the morbidity and mortality associated with infections.
