Objectives: For better characterizing the effect of anti-CD20 therapy, we analysed the use of rituximab in Belgian patients experiencing auto-immune haemolytic anaemia (AIHA) and immune thrombocytopenic purpura (ITP).
Design: We performed a retrospective multicentric analysis of patients with AIHA and ITP treated with rituximab in Belgium.
Setting: Haematological departments were invited to fill in a questionnaire about patient and disease characteristics.
Subjects: All patients with AIHA and ITP, both primary and secondary to other diseases, who received one or more courses of rituximab during their disease course were included. Sixty-eight courses of rituximab in 53 patients with AIHA and 43 courses in 40 patients with ITP were analyzed.
Intervention: Response rates, duration of response and factors predictive for response were assessed.
Results: All patients were given rituximab after failing at least one previous line of treatment, including splenectomy in 19% and 72.5% of AIHA-patients and ITP-patients respectively. Overall response rates were 79.2% in AIHA and 70% in ITP, with a median follow-up since first rituximab administration of 15 months (range 0.5-62) in AIHA and 11 months (range 0-74) in ITP. Progression free survival at 1 and 2 years were 72% and 56% in AIHA and 70% and 44% in ITP. In this retrospective analysis we were not able to identify pretreatment characteristics predictive for response to rituximab. Nine patients with AIHA and three patients with ITP were given one or more additional courses of rituximab. Most of these patients, who had responded to a previous course, experienced a new response comparable to the previous one, both in terms of quality and of duration of response. Finally, the outcome of patients who failed to respond to rituximab therapy was poor both in terms of response to subsequent therapy and in terms of survival.
Conclusions: This study confirms that rituximab induces responses in a majority of previously treated patients with AIHA and ITP. Response duration generally exceeds 1 year. Retreatment with rituximab in responding patients is most often successful. The outcome of patients who fail on rituximab is poor. We were not able to identify pretreatment patient characteristics predicting for response.