PB2261: LINEZOLID AS A SAFE ANTIMICROBIAL AGENT IN THROMBOCYTOPENIC PATIENTS UNDERGOING CHEMOTHERAPY FOR HEMATOLOGIC MALIGNANCIES

Abstract

Background: Febrile neutropenia (FN) is a common event in patients undergoing high-dose chemotherapy (HD-CT) for hematologic malignancies. Linezolid (LZ) is the first-in-class oxazolidinone antimicrobial agent active against gram-positive bacteria, often administered during FN as treatment for hospital-acquired pneumonia, gram-positive bacteriemia and soft-skin tissue infection. LZ induced thrombocytopenia or delayed platelet recovery are adverse events of concern in patients receiving HD-CT. As of today, few data are available on the safety of LZ in this specific setting. Aims: To retrospectively analyze a cohort of thrombocytopenic patients treated with LZ for FN in a single center, evaluating bleeding risk and impact on PLT recovery time. Methods: The analysis included patients diagnosed with Acute Leukemia (AL), High Grade Lymphomas (HGL) and Multiple Myeloma (MM) treated at our institution, between 2016 and 2021, with LZ for a FN episode during induction chemotherapy or ASCT conditioning. To be enrolled, PLT count at the start of LZ therapy had to be < 50×109/L. Results: A total of 40 FN episodes treated with LZ were identified. 22 occurred during induction therapy for AL and 18 during ASCT conditioning regimens. The median PLT count at the start of LZ therapy was 19×109/L in both groups (range 5-49×109/L in the AL cohort, 5-35×109/L in the ASCT group), while the median treatment duration was 8 days in both groups (range 2-15 days in the AL cohort, 3-12 days in the ASCT cohort). Only one clinically relevant bleeding event was observed in the AL group, while 0 bleeding events were observed in the ASCT group. Resolution of infection (defined as fever resolution, normalization of CRP and blood culture negativization) after the introduction of LZ therapy was observed in 17 (77%) AL patients and 15 (83%) ASCT patients. In the AML group PLT recovery (defined as a stable PLT count ≥20×109/L without the need for PLT transfusion) was observed in 18 (81%) patients with a median time to recovery of 22 days from the start of the chemotherapeutic regimen (range 18-41). PLT recovery was observed in 10 (71%) ASCT patients with a median time to recovery of 35 days from the stem cell infusion (range 13-136). 4 out of 18 patients in the ASCT group started LZ therapy after PLT recovery, and 3 out of 18 patients in the same group died due to the infectious complication that prompted the start of LZ therapy. Median PLT recovery time was not significantly different between patients enrolled in this study and historical controls from our center (AML: median 20 days, p>0.1. ASCT: median 22.5 days, p>0.1). Summary/Conclusion: Our observations support the use of LZ in this setting, as only one relevant bleeding event was observed among the two groups, and no impact on PLT recovery time was noted after comparison with historical data. Our study suggests that LZ is a safe and effective antimicrobial therapy in patients undergoing HD-CT for hematological malignancies. This data needs to be prospectively confirmed in a larger cohort of patients in a multicenter study.