Clinical Trials Experience in GPA and MPA
Adverse reactions reported in ≥15% of Rituxan-treated patients were infections, nausea, diarrhea, headache, muscle spasms, anemia, peripheral edema, infusion-related reactions.
Induction Treatment of Patients with Active GPA/MPA (GPA/MPA Study 1)
Infusion-Related Reactions: In GPA/MPA Study 1, 12% vs 11% (Rituxan-treated vs cyclophosphamide) of patients experienced at least one infusion-related reaction. Infusion-related reactions included cytokine release syndrome, flushing, throat irritation, and tremor. In the Rituxan group, the proportion of patients experiencing an infusion-related reaction was 12%, 5%, 4%, and 1% following the first, second, third, and fourth infusions, respectively. Patients were premedicated with antihistamine and acetaminophen before each Rituxan infusion and were on background oral corticosteroids, which may have mitigated or masked an infusion-related reaction; however, there is insufficient evidence to determine whether premedication diminishes the frequency or severity of infusion-related reactions.
Infections: In GPA/MPA Study 1, 62% vs 47% (Rituxan-treated vs cyclophosphamide-treated, respectively) of patients experienced an infection by Month 6. The most common infections in the Rituxan group were upper respiratory tract infections, urinary tract infections, and herpes zoster. The incidence of serious infections was 11% vs 10% (Rituxan-treated vs cyclophosphamide, respectively), with rates of approximately 25 and 28 per 100 patient-years, respectively. The most common serious infection was pneumonia.
Hypogammaglobulinemia: Hypogammaglobulinemia (IgA, IgG, or IgM below the lower limit of normal) has been observed in patients with GPA and MPA treated with Rituxan in GPA/MPA Study 1. At 6 months, in the Rituxan group, 27%, 58%, and 51% of patients with normal immunoglobulin levels at baseline had low IgA, IgG, and IgM levels, respectively compared to 25%, 50%, and 46% in cyclophosphamide group.
Treatment of Patients with GPA/MPA who have Achieved Disease Control with Induction Treatment (GPA/MPA Study 2)
In GPA/MPA Study 2, the safety profile was consistent with the known safety profile of Rituxan in immunologic indications.
Infusion-Related Reactions: In GPA/MPA Study 2, 7/57 (12%) patients in the EU-approved rituximab arm reported infusion-related reactions. The incidence of IRR symptoms was highest during or after the first infusion (9%) and decreased with subsequent infusions (<4%). One patient had two serious IRRs, two IRRs led to a dose modification, and no IRRs were severe, fatal, or led to withdrawal from the study.
Infections: In GPA/MPA Study 2, 30/57 (53%) patients in the EU-approved rituximab arm and 33/58 (57%) in the azathioprine arm reported infections. The incidence of all grade infections was similar between the arms. The incidence of serious infections was similar in both arms (12%). The most commonly reported serious infection in the group was mild or moderate bronchitis.
Treatment of Pediatric Patients with GPA/MPA (GPA/MPA Study 4)
The safety profile in pediatric GPA and MPA patients was consistent in type, nature and severity with the known safety profile of Rituxan in adult patients with FDA-approved immunological indications.
In GPA/MPA Study 4, the proportion of patients experiencing an IRR was 32%, 20%, 12%, and 8% following the first, second, third, and fourth infusions, respectively. The observed symptoms of IRRs were similar to those in adult GPA and MPA patients treated with Rituxan.
In GPA/MPA Study 4, serious infections were reported in 7 patients (28%), and included influenza (2 patients [8%]) and lower respiratory tract infection (2 patients [8%]) as the most frequently reported events.
Hypogammaglobulinemia (IgG or IgM below the lower limit of normal), including prolonged hypogammaglobulinemia (defined as Ig levels below lower limit of normal for at least 4 months) was observed in GPA/MPA Study 4. During the overall study period, 18/25 patients (72%) had prolonged low IgG levels, including 15 patients who also had prolonged low IgM. Three patients received treatment with intravenous immunoglobulin
A total of 23/99 (23%) Rituxan-treated patients with GPA or MPA tested positive for anti-rituximab antibodies by 18 months in GPA/MPA Study 1. The clinical relevance of anti-rituximab antibody formation in Rituxan-treated patients is unclear. In GPA/MPA Study 4, a total of 4/21 (19%) Rituxan-treated pediatric patients with GPA and MPA developed anti-rituximab antibodies during the overall study period (assessed at Month 18).