Use of rituximab maintenance infusions in relapsing responders with ITP and AIHA

Background: Rituximab is an often effective treatment of ITP (Immune thrombocytopenia). However treated patients who respond often relapse. While they may have an almost identical response to retreatment, this includes relapsing again in the same time frame (Hasan, AmJHem, 2009). To evaluate the efficacy of rituximab maintenance in ITP patients responding to but relapsing after Rituximab. Methods: Sixteen relapsed patients were infused with 6 single infusions of 4monthly or other additional rituximab over 2 years following a 2nd 4-infusion course of rituximab. The duration of their response was compared to their response to their first course of rituximab. Results: Of 16 eligible patients, 9 had AHA, 7 ITP. All patients responded to their second 4-infusion course of rituximab. 7 patients finished the 6 maintenance infusions; 5/7 are still maintaining their remission for a median of 44 months following the 2 cycle of rituximab. One patient received 4 courses of 4-infusions of rituximab and is maintaining remission at 35 months. Two others are either too early to assess (1) or lost to f/u (1). Two patients are receiving maintenance and in remission currently. Three received 6 infusions but are in long-term remission. One (and one of the two who relapsed after 6 maintenance infusions) no longer responds to rituximab. No important toxicity was seen. JC virus cultures were negative in several of the patients. Three patients developed hypogammaglobulinemia and needed IVIG prophylaxis against infections; one patient had bacteremia and one, pneumonia. Conclusion: Rituximab maintenance infusion achieves a much longer lasting remission than only a second course of rituximab: 9 patients are in lasting remissions many months after their last rituximab infusion. Rituximab maintenance is an effective and seemingly safe addition to standard rituximab as a therapeutic option to treat refractory ITP.