Daptomycin use in patients with cancer and neutropenia: Data from a retrospective registry

Clinical data for daptomycin in the treatment of neutropenic cancer patients with documented gram-positive infections are limited. For this study, neutropenic patients were identified from an ongoing retrospective registry (Cubicin Outcome Registry and Experience [CORE]; 2006 program year). Clinical outcomes included cure, improved, failed, and nonevaluable response, and were assessed at the end of daptomycin therapy. Patients who had a nonevaluable clinical response were only included in the safety analysis. Eighty-four patients were identified, of which 72 (86%) were clinically evaluable. Thirty-four (47%) evaluable patients had severe neutropenia (<100 cells/mm³). Hematologic malignancies were most common (82%). Bacteremia was the most common infection (76%), and vancomycin-resistant enterococci (50%), coagulase-negative staphylococci (24%), and Staphylococcus aureus (11%) were the most common pathogens isolated. Sixty-three patients (88%) received prior antibiotics, including vancomycin (83%), cefepime (17%), and linezolid (16%). The overall success rate (cure + improved) was 90%. Success rates stratified by degree of neutropenia were 85% for patients with less than 100 cells/mm³, 93% for those with 100-499 cells/mm³, and 100% for those with 500-1,000 cells/mm³. The median final daptomycin dose was 6 mg/kg (range, 3-8) and the median duration of therapy was 13 days (range, 1-86). Of the 84 patients analyzed for safety, 24 (29%) developed 44 adverse events; only 5 (6%) patients had adverse events possibly related to daptomycin. The results suggest that daptomycin may be useful for specific cases involving neutropenic patients, and comparative clinical trials are feasible.