Infectious complications after 2-chlorodeoxyadenosine therapy

Infection is a common adverse event after therapy with nucleoside analogs, including 2-chlorodeoxyadenosine (CdA). However, the incidence of CdA-related infections has been poorly documented. In this study we compare, in the same patient population, the incidence of infectious episodes during the 6-month period before CdA to their incidence during the 6 months after initiating therapy. Ninety-five patients with hematological malignancies were studied. The incidence of infectious episodes almost doubled after CdA (0.87 vs. 0.47 during the pre-CdA period). The following factors were associated with an increased risk of infection after therapy: a history of previous chemotherapy, infection during the pre-CdA period and a diagnosis of chronic lymphocytic leukemia or of non-Hodgkin's lymphoma. Age, neutrophil and lymphocyte count at onset of CdA and time interval between diagnosis and therapy with CdA did not correlate with the infectious risk. The pattern of infections was modified after therapy with an increase of herpes virus infections ( 1 vs. 8 episodes, p=0.04) and of fever of unknown origin (6 vs. 17 episodes, p=0.03). In conclusion, a population at high risk for developing infectious complications after CdA therapy can be identified. Specific measures aimed at reducing the incidence of infectious events should concentrate on this population.