A new model for predicting infectious complications during fludarabine‐based combination chemotherapy among patients with indolent lymphoid malignancies

BACKGROUND Fludarabine‐containing combination chemotherapy regimens are increasingly used in the treatment of indolent lymphoid malignancies, with the associated risk of infection being the major toxicity. Predictors of infection during fludarabine‐containing combination therapy are poorly defined and optimal strategies for infection prophylaxis are not known. The authors analyzed their experience with patients treated with the fludarabine‐mitoxantrone (FM) or fludarabine‐cyclophosphamide (FC) regimens to develop a predictive model for infections. METHODS Ninety‐two patients with indolent lymphoid malignancies were treated with FM (n = 29) or FC (n = 63). Baseline variables including age, gender, regimen, disease histology, previous therapy, time from diagnosis to current treatment, performance status, renal function, absolute neutrophil count (ANC), lymphocyte count, and immunoglobulin G levels were examined retrospectively for their association with risk of infectious complications during or within 4 weeks of therapy. RESULTS Six risk factors were associated with infectious complications: age > 60 years, ≥ 3 previous therapies, previous fludarabine exposure, time from diagnosis to current treatment of > 3 years, performance status ≥ 2, and baseline ANC < 2.0 × 109/L. Compared with patients with 0–2 risk factors, patients with ≥ 3 risk factors had higher infection rates (26% vs. 7% per cycle, P < 0.0001), more Grade 4 neutropenia (41% vs. 8% per cycle, P < 0.0001), and more neutropenic sepsis (15% vs. 1% per cycle, P < 0.0001). CONCLUSIONS Infection risk during fludarabine‐containing combination chemotherapy was predicted with a model comprising six baseline risk factors. Patients predicted to be at high risk of infection were an appropriate group for consideration of prophylactic strategies. Cancer 2004. © 2004 American Cancer Society. Baseline variables for 92 patients with indolent lymphoid malignancies treated with fludarabine‐based combination chemotherapy were analyzed for their association with infectious complications. A predictive model based on six baseline variables identified patients at high risk of infections during such therapy.