Real-world utilization patterns of intravenous immunoglobulin in adults with generalized myasthenia gravis in the United States.

OBJECTIVE

To evaluate real-world utilization patterns of intravenous immunoglobulin (IVIg) among patients with generalized myasthenia gravis (gMG) over 3 years post-IVIg initiation.

METHODS

Patients with gMG who initiated IVIg treatment were identified from a United States claims database (Symphony Health's Integrated Dataverse [IDV]®, January 1, 2014 - December 31, 2019). The frequency of subsequent IVIg treatment and associated cost during the year post-IVIg initiation were analyzed. Usage patterns of IVIg and concomitant gMG treatments during the year preceding and 3 years post-IVIg initiation were compared.

RESULTS

Among 1225 patients with gMG who initiated IVIg treatment, 706 patients (57.6%) received 1 to 5 IVIg treatment courses (intermittent IVIg users), and 519 patients (42.4%) received ≥6 IVIg treatment courses (chronic IVIg users) within the subsequent year. Mean annual medical cost per patient was nearly 2.5-fold higher for chronic vs. intermittent IVIg users ($161,478 vs. $64,888, p < 0.001). The proportion of patients using corticosteroids and nonsteroidal immunosuppressive treatments (NSISTs) was not reduced over the 3-year follow-up period following IVIg initiation, even for patients who continued annual chronic IVIg for 3 consecutive years post-initiation.

CONCLUSIONS

Nearly half of patients with gMG received chronic and multiple IVIg treatment courses within the first year once initiating IVIg treatment, indicating higher usage than expected. For all IVIg initiators, the proportion of patients using corticosteroids and NSISTs did not decrease over 3 years despite IVIg initiation.