The addition of rituximab to a dexamethasone regimen was associated with improved platelet response rates in a cohort of patients with immune thrombocytopenia, according to results of a randomized, open-label, phase 3 trial.
The study included 133 newly diagnosed adults. Eligibility criteria included platelet counts ≤25 × 109/L or ≤50 × 109/L with bleeding symptoms.
Researchers randomly assigned 71 patients to dexamethasone 40 mg/day for 4 days, and 62 patients were assigned this dexamethasone regimen plus rituximab (Rituxan, Genentech/Biogen Idec) 375 mg/m2 weekly for 4 weeks. The study protocol allowed patients a supplemental dexamethasone course every 1 to 4 weeks for up to six cycles.
Sustained response — defined as platelets ≥50 × 109/L — at 6 months follow-up served as the primary endpoint. The median follow-up duration was 922 days.
The endpoint was reached by 37% of patients in the dexamethasone-only group and 58% of patients in the combination group (P=.02).
Patients in the combination arm also demonstrated longer time to relapse (P=.03) and time to rescue treatment (P=.007).
Safety profiles indicated more grade 3 to 4 adverse events in the combination group (P=.04).