Rituxan Deemed Safe, Effective for Refractory or Relapsing GPA Patients
Genentech‘s Rituxan (rituximab) is safe and effective to induce and maintain remission in patients with refractory or relapsing granulomatous manifestations (inflamed tissue) due to granulomatosis with polyangiitis (GPA), according to a new study.
The findings were presented at the recent 19th International Vasculitis and ANCA Workshop in Philadelphia, Pennsylvania, in a poster titled, “Rituximab Therapy for Refractory/Relapsing Granulomatous Manifestations Due to Granulomatosis with Polyangiitis.”
GPA is a subtype of ANCA-associated vasculitis (AAV), an autoimmune inflammatory disorder characterized by inflammation and damage to small and medium-sized blood vessels.
Treatment consists of immunosuppressive therapy, which often includes glucocorticoids in combination with Rituxan, that works to reduce the activity of the immune system.
Rituxan is an antibody that targets B cells, a type of immune cell that makes antibodies and plays a role in autoimmune diseases. While Rituxan is approved and commonly used for AAV treatment, it is not known whether it is able to induce and maintain remission in GPA patients with refractory or relapsing granulomatous manifestations.
Aiming to fill this gap, a group of Spanish researchers conducted a retrospective study of all GPA patients with refractory or relapsing granulomatous manifestations who were treated with Rituxan between 2010-2018 at a tertiary center.
They collected clinical characteristics, blood test results, and the Birmingham Vasculitis Activity Score/Wegener Granulomatosis (BVAS/WG), a measure of GPA disease activity.
The study included 14 patients, all of whom received Rituxan plus glucocorticoids. Nine patients also received additional immunosuppressive drugs. At the time of Rituxan infusion, the BVAS/WG score ranged between 6 and 12; 10 patients were positive for ANCA antibodies.
Researchers found that treatment with Rituxan led to a reduction in B cells and a depletion of ANCA antibodies in all patients.
Additionally, 10 patients achieved complete remission and three had partial remission. Glucocorticoid dosage was brought down to 5 mg per day at month six in all patients and discontinued in four patients. Other immunosuppressants were withdrawn in five patients.
However, six patients experienced one relapse and two patients experienced three and five relapses, respectively. These were associated with higher B-cell levels and return of ANCA antibodies in all but three cases.
All relapsing patients were successfully re-treated with Rituxan, and three patients were pre-emptively re-treated with Rituxan.
One patient died of a severe infection associated with late-onset neutropenia (abnormally low levels of neutrophils, a type of white blood cell) and hypogammaglobulinemia (an immune disorder characterized by a reduction in all types of antibodies).
“[Rituxan] is useful and safe for induction and maintenance of remission in patients with refractory/relapsing granulomatous manifestations due to GPA,” researchers concluded. “Most patients achieve a prolonged remission after RTX. ANCA and CD19+B-cells counts are useful to guide the timing of re-treatment.”