medwireNews: Levofloxacin prophylaxis significantly reduces the risk for bacteremia among children receiving intensive chemotherapy for acute leukemia, but not among those undergoing hematopoietic stem cell transplantation (HSCT), study data show.
“The observed risk reduction was similar to findings from adult studies,” Sarah Alexander (The Hospital for Sick Children, Toronto, Ontario, Canada) and co-authors remark.
The multicenter trial included 195 children aged 6 months to 21 years with acute leukemia (median age 11 years, 46% female) and 418 similarly aged individuals undergoing allogeneic or autologous HSCT (median age 7 years, 38% female).
Patients from each group were randomly assigned to receive levofloxacin prophylaxis (10 mg/kg once or twice daily) or no prophylaxis during two consecutive cycles of chemotherapy or one HSCT procedure.
The researchers found that, among the patients with acute leukemia, the incidence of bacteremia was significantly lower in the levofloxacin prophylaxis group than in the control group, at a rate of 21.9% versus 43.4%.
By contrast, there was no significant difference in bacteremia incidence between the intervention and control groups among the children undergoing HSCT, at 11.0% versus 17.3%.
Patients who received levofloxacin were significantly less likely to experience the combined outcome of fever and neutropenia than those who received no prophylaxis (71.2 vs 82.1%). But there were no significant between-group differences in the rates of severe infection (3.6 vs 5.9%), invasive fungal disease (2.9 vs 2.0%), Clostridium difficile–associated diarrhea (2.3 vs 5.2%), or musculoskeletal toxicity after 2 months (11.4 vs 16.3%) and 1 year (10.1 vs 14.4%).
Of note, a post-hoc analysis that accounted for time at risk found that patients in both the acute leukemia and HSCT groups had significantly lower rates of bacteremia with levofloxacin prophylaxis than without it, at 4.9 versus 9.4 cases of bacteremia per 1000 patient–days and 5.3 versus 10.0 cases per 1000 patient–days, respectively.
This finding supports the theory that “the effect [of levofloxacin] was similar in the 2 groups but that there was reduced power to detect a significant difference related to fewer events among patients undergoing HSCT,” Alexander et al write in JAMA.
They add, however, that “it is also plausible that the leukemia and HSCT groups had different supportive care measures or were infected with pathogens that had differential sensitivity to levofloxacin resulting in different efficacy of levofloxacin in the 2 groups.”
The researchers also point out that although levofloxacin prophylaxis significantly decreased the rate of bacteremia among patients with acute leukemia, there were still 123 bacteremia episodes caused by 136 organisms, most commonly viridans group streptococci.
“This finding suggests that levofloxacin prophylaxis will not eliminate the risk of these important infections,” they remark.
Therefore “[o]ther interventions will likely need to be combined with levofloxacin prophylaxis to further decrease bacteremia risk,” Alexander and team conclude.
By Laura Cowen
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