Mabthera (Rituximab) in the Treatment of 34 Adult Patients with Refractory Autoimmune Hemolytic Anemia (AIHA).

Objectives: Rituximab (RB) is an anti-CD20 murine/human chimeric antibody that has been used in the treatment of auto-immune diseases. RB has shown to be effective in childhood AIHA but data on adults are lacking. The effectiveness of RB in the treatment of adult patients with AIHA has been evaluated.

Patients and methods: A multicentric retrospective study of patients with AIHA treated with RB has been carried out. A questionnaire about clinical characteristics and response to RB was sent to the participating centers. These questionnaires were filled out by the physician in charge of each patient. We received questionnaires from 20 centers (34 patients). Response criteria were defined as follows: Complete Response (CR): Hb >10 g/dl or Hb increase >1.5 g/dl; Partial Response (PR): Hb > 9 g/dl or Hb increase of 1–1.5 g/dl. Median age was 64 years (20–86), 62% were women. 13 cases were idiopathic and the remaining 20 were associated with chronic lymphoproliferative syndromes (CLS) (14), connective tissue diseases (2), allogeneic hematopoietic stem cell transplantation (2), liver transplant (1), amiloidosis (1) and MGUS (1). In 6 cases the immune hemolysis was due to cold-reactive antibodies. Before RB they have received several treatment schemes, 12 patients were splenectomized and only 6 (17.6%) had not been transfused. Median Hb before the treatment with RB was 6.9 g/dl (3.3–12.7). 27 patients received 4 doses of RB (1–6), 24 received it in association with other treatments, mainly steroids.

Results: 19 patients obtained CR (63%) and 4 patients obtained PR (13%). In 50 % of the cases the Coombs antiglobulin test became negative. The majority of the responses took place in 3 weeks (1–8) and maximum responses in 10 weeks (1–35). 15 out of the 19 patients that obtained CR, reached it from the beginning of the response. 82% (9/11) of the patients with AIHA associated to CLS obtained CR, 58% (7/12) of the patients with idiopathic AIHA obtained CR and 17% (2/12) PR. 50% (3/6) of the patients with immuno-hemolytic anemia due to cold-reactive antibodies obtained CR. There were no differences in the response between splenectomized and not splenectomized patients. Median increase in Hb level was 5.9 g/dl (1.2–9.8) with a monitoring median of 8.7 months (1–48). There were no significant toxicities.

Conclusions: These results suggest that RB can be effective in the treatment of adult patients with AIHA, both idiopathic and associated with CLS, with a very low toxicity profile.