Cold agglutinin disease revisited: a multinational, observational study of 232 patients.

We retrospectively studied 232 patients with cold agglutinin disease (CAD) at 24 centers in 5 countries. In Norway and a northern region of Italy, the study was close to being population-based. For the first time, we demonstrate fourfold differences between cold and warmer climates regarding prevalence (20 vs 5 cases/million) and incidence (1.9 vs 0.48 cases/million per year). Mean baseline hemoglobin level was 9.3 g/dL, but 27% had hemoglobin <8 g/dL. Identification of typical features of CAD-associated lymphoproliferative disorder in the bone marrow was greatly increased by centralized biopsy assessment. CAD seems to be associated with a slightly increased risk of venous thrombosis. This work includes a follow-up study of therapies, focusing on the long-term outcomes of the rituximab plus bendamustine and rituximab plus fludarabine regimens. Rituximab plus bendamustine therapy resulted in responses in 35 (78%) of 45 patients; 24 (53%) achieved complete response. Interestingly, these rates were still higher than observed in the original (2017) prospective trial, and we also found a shift toward deeper responses with time. This is explained by the prolonged time to response seen in many patients, probably related to long-lived plasma cells. In patients responding to rituximab-bendamustine, median response duration was not reached after 88 months, and estimated 5-year sustained remission was 77%. The regimen appeared safe regarding late-occurring malignancies. Rituximab plus fludarabine therapy seems to carry a higher risk of long-term adverse effects.

Bendamustine plus rituximab for chronic cold agglutinin disease: results of a Nordic prospective multicenter trial.

Primary chronic cold agglutinin disease (CAD) is a well-defined clinicopathologic entity in which a bone marrow clonal B-cell lymphoproliferation results in autoimmune hemolytic anemia and cold-induced circulatory symptoms. Rituximab monotherapy and fludarabine-rituximab in combination are documented treatment options. In a prospective, nonrandomized multicenter trial, 45 eligible patients received rituximab 375 mg/m2 day 1 and bendamustine 90 mg/m2 days 1 and 2 for 4 cycles at a 28-day interval. Thirty-two patients (71%) responded; 18 (40%) achieved complete response (CR) and 14 (31%) partial response (PR). Among 14 patients previously treated with rituximab or fludarabine-rituximab, 7 (50%) responded to bendamustine-rituximab (3 CR and 4 PR). Hemoglobin levels increased by a median of 4.4 g/dL in the complete responders, 3.9 g/dL in those achieving PR, and 3.7 g/dL in the whole cohort. The 10th percentile of response duration was not reached after 32 months. Grade 3-4 neutropenia occurred in 15 patients (33%), but only 5 (11%) experienced infection with or without neutropenia. Thirteen patients (29%) had their dose of bendamustine reduced. In conclusion, bendamustine-rituximab combination therapy is highly efficient, sufficiently safe, and may be considered in first line for patients with CAD requiring therapy. The trial was registered at www.clinicaltrials.gov as #NCT02689986.