Effect of Linezolid on Hematologic Recovery in Newly Diagnosed Acute Myeloid Leukemia Patients Following Induction Chemotherapy

Objective Assess the effects of linezolid on hematologic outcomes in newly diagnosed patients with acute myeloid leukemia (AML) following induction chemotherapy. Design Single-center, retrospective, observational, cohort study. Setting Large, tertiary care academic medical center. Patients A total of 225 patients ≥ 18 years admitted between December 2010 and 2013 with newly diagnosed AML were assessed for inclusion. Patients were identified through the use of ICD-9 codes and chemotherapy ordered via the computerized physician order entry system. Sixty-eight patients met inclusion criteria and were grouped into two arms based on antimicrobial treatment: LZD group (linezolid plus gram-negative antimicrobial, n=21) or control group (vancomycin or daptomycin plus gram-negative antimicrobial, n=47). Interventions The LZD group received linezolid ≥ 72 hours. The control group received vancomycin or daptomycin ≥ 72 hours. If patients switched extended gram-positive therapy, they were included in the LZD group as long as they had received ≥ 72 hours of linezolid. Measurements/Results The primary end point of time to neutrophil recovery was not statistically different (28 days for LZD group vs 26 days for control group; p=0.675). The preplanned subgroup analysis of patients who received ≥ 14 days of linezolid demonstrated statistically similar median times to neutrophil recovery (29 days for LZD group vs 26 days for control group; p=0.487). Total duration of extended gram-positive antimicrobial therapy was significantly longer in the LZD group (27 days vs 16 days; p<0.001). Secondary end points not found to be statistically significant included platelet count at time of neutrophil recovery, duration of neutropenia, and length of hospital stay. Conclusions There were no significant differences in hematologic outcomes in newly diagnosed AML patients who received linezolid for extended gram-positive antimicrobial coverage following induction chemotherapy. This study provides new insight with a primary focus on the effects of hematologic outcomes when using linezolid in a well-defined acute leukemia population. Further study is warranted with larger populations to assess the potential adverse effects linezolid may have in patients with acute leukemia.