(PA-529) Risk of Infections After Bispecific Antibodies Targeting Anti-B-cell Maturation Antigen (BCMA) in Multiple Myeloma- intravenous Immunoglobulin (IVIG) Significantly Lowers the Risk of Infection

Elranatamab and teclistamab are bispecific antibodies (BsAb) against B-cell maturation antigen (BCMA) and are highly effective in treatment of multiple myeloma (MM). Due to lowered humoral immunity, infections are common with BsAb and Intravenous Immunoglobulin (IVIG) is recommended for infection prophylaxis. Here, we report the incidence of infections, utilization patterns and effect of IVIG use among patients with MM receiving elranatamab and teclistamab using large-scale real-world data.

Methods:

We conducted a retrospective analysis of de-identified electronic health records from Epic Cosmos, which covers more than 1700 hospitals and 40000 clinics in the United States. Adult patients (>18 years old) diagnosed with MM, with >2 doses of elranatamab or teclistamab and with >6 months of data collected in Epic Cosmos were included. Patients were followed from first to last administration of BsAb. International Classification of Disease-Clinical Modification (ICD-CM)-10 codes were used. Infection episodes were considered distinct if consecutive ICD codes indicating infection were more than 56 days apart or if a new ICD code was used. Proportion of patients with each type of toxicity, rate of toxicities and time to first toxicity were quantified. Rate of infections before and after IVIG was compared using paired t-test.

Results:

A total of 1646 MM patients (1491 received teclistamab and 155 received elranatamab) met study eligibility and had a median follow-up of 7.1 months (interquartile range [IQR], 1.8-13.0). Median age at the time of initiation of BsAb was 70 years (IQR, 63-76) and 881 (53.5%) were male. Majority (n=1402, 86%) lived in urban areas, 1042 (63.3%) identified as white and 808 (49.1%) were anti-CD38 exposed. Median time from diagnosis to BsAb initiation was 4.7 years (IQR, 2.3-7.5). During treatment with BsAb, 493 patients (30%) were documented to have at least 1 infection with an infection rate of 0.06 (standard deviation [SD], 0.27) episode/patient-month and median time to first infection was 2 months (IQR, 0.7-5.1). Bacterial sepsis was the most common type of infection (n = 200, 12.2%), followed by febrile neutropenia (n = 126, 7.7%) and viral pneumonia (n = 89, 5.4%). The risk of infection was higher amongst those who received teclistamab (n = 458, 30.7%) compared to those who received elranatamab (n = 35, 22.6%), p = 0.03. Almost half of patients (n = 826, 50.2%) received IVIG while on BsAb and among these patients, infection rate decreased from 0.09 (SD, 0.27) episode/patient-month prior to IVIG use to 0.03 (SD, 0.15) episode/patient-month after IVIG use (p < 0.001).

Conclusions:

In this largest nationwide cohort of MM patients treated with anti-BCMA BsAb, only half of the patients received IVIG and use of IVIG was associated with a 67% decrease in infections. More awareness is needed to expand the use of IVIG to prevent infections in patients receiving BsAbs and prospective studies would be crucial to establish its optimal dosing schedules.