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Incidence of Hypogammaglobulinemia in Patients Receiving Ocrelizumab or Rituximab for the Treatment of MS and Nmosd
Ocrelizumab and rituximab are monoclonal antibodies targeting the CD20 marker on B lymphocytes. B lymphocyte depletion poses a risk of decreased immunoglobulin (Ig) levels.
Objectives:
To evaluate the rates and predictors of hypogammaglobulinemia in patients with MS, NMOSD, and related disorders that were treated with ocrelizumab or rituximab.
Methods:
A retrospective study was completed among patients receiving ocrelizumab or rituximab for the treatment of MS, NMOSD, and other related neurologic disorders at University Hospitals Neurological Institute from May 2017 through January 2022. An analysis of baseline and clinical characteristics was carried out to identify differences between those that did and did not develop hypogammaglobulinemia. Significant differences were evaluated in a multivariate logistic regression model to identify predictors of hypogammaglobulinemia.
Results:
A total of 184 patients (mean age 48.4 ± 13.6 years; 67% female) met inclusion criteria; 152 (83%) patients received ocrelizumab and 32 (17%) patients received rituximab. Twenty-two patients (12%) had hypogammaglobulinemia during treatment. Rituximab use was seen more commonly among those with hypogammaglobulinemia compared to those without (p=0.0123). Patients who developed hypogammaglobulinemia were also more likely to have been at least 50 years of age (p=0.0275) with lower pretreatment IgG (p=0.001) and IgA (p=0.0038) levels. Logistic regression identified age of at least 50 years (p=0.0079) and rituximab therapy (p=0.0030) as independent predictors of hypogammaglobulinemia in patients treated with anti-CD20 therapy. There was a trend towards higher rates of serious infection in patients with hypogammaglobulinemia (22.7% vs 9.9%; p=0.0753).
Conclusions:
Among patients treated with ocrelizumab or rituximab, the development of hypogammaglobulinemia occurred in 12% of patients, but was more common in patients on rituximab, at least 50 years old, and with lower baseline IgG and IgA levels. Rituximab use and advanced age (≥ 50 years) were identified as independent predictors of hypogammaglobulinemia. Rates of serious infection were numerically higher among those who developed hypogammaglobulinemia on anti-CD20 therapy.