Favourable response to therapy with the anti-CD20 monoclonal antibody rituximab in primary chronic cold agglutinin disease

The 'primary' form of chronic cold agglutinin disease is a clonal B-cell ly mphoproliferative disorder that is notoriously difficult to treat with drug s, including corticosteroids, alkylating agents, alpha-interferon and purin e analogues. We performed a small, open, uncontrolled, prospective study to evaluate the effect of therapy with the monoclonal anti-CD20 antibody ritu ximab. Six patients with clonal CD20(+)kappa (+) B-cell proliferation recei ved seven courses of rituximab 375 mg/m(2), d 1, 8, 15, and 22. One patient achieved a complete response. Four partial responses were observed, includ ing a response to re-treatment in one patient. Two patients were categorize d as non-responders. Haemoglobin levels increased by a median of 4.1 g/dl i n the total group and 4.7 g/dl in the responders, who also experienced a su bstantial improvement of clinical symptoms. The treatment was well tolerate d. We discuss the effect of rituximab therapy compared with other treatment options, and try to explain why two individual patients did not respond. D espite the small numbers, the results are very encouraging. Further studies of rituximab therapy for chronic cold agglutinin disease are warranted.