Benefit of Anti-Infectious Prophylaxis in Patients with Acute Myeloid Leukemia or High-Risk Myelodysplastic Syndrome Receiving Frontline “Targeted Therapy”.

Background Patients with high risk (HR) myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) have significant toxicities such as mucositis, protracted neutropenia and severe infections when treated with standard chemotherapy. This had led to the development of ‘less intense’ chemotherapy (targeted therapy, TT). These treatments are expected to produce less toxicities, especially less immunosuppression. Antibiotic and antifungal prophylaxis are routinely given to patients undergoing intensive chemotherapy. It is not clear if the same strategy should be used for patients receiving less intensive chemotherapy. The objective of this study is to evaluate the outcome of patients receiving TT according to the use of antimicrobial prophylaxis. Methods We retrospectively reviewed the medical records of patients with AML and HR MDS that received TT as induction therapy from January 2000 to July 2007 at our institution. Baseline characteristics and antibiotic usage was recorded. All courses of TT received from start of therapy until outcome (response or failure) was assessed were evaluated, and infections or death occurring during any of these courses constituted an event. Results 225 patients received TT [decitabine or azacitidine n = 137 (61%); miscellaneous (tipifarnib, PKC412, imatinib, SAHA, and others) n=88 (39%)] for a total of 583 courses (median course per patient = 2). Median age was 72 years (range 13–89), 60% were male, 95% had Zubroad performance status ≤ 2 and 28% were neutropenic at the start of TT. None of the patients were placed in HEPA-filtered rooms (‘protected environment’) at any time. Each course of therapy was grouped into 1 of 4 groups based on the strategy use for infectious prophylaxis (table 1). Clinically documented infections and FUO were the most frequent type of infection reported in all the groups, followed by bacterial infections. Fungal infections were infrequent (total 5; group 1 = 1; group 2 = 2, group 3 = 2). There was no significant difference in the number of infectious episodes per course between the groups that received both antibacterial and antifungal prophylaxis vs. those who received no prophylaxis (p= 0.984). However, mortality was significantly higher during courses of TT administered without prophylaxis (p= 0.005). Conclusions As opposed to standard chemotherapy, fungal infections are infrequent in the patients treated with TT. Mortality is significantly higher in patients who did not receive any anti-microbial prophylaxis. The use of antibacterial and antifungal prophylaxis should be considered in patients receiving TT. Table 1: Groups based on antimicrobial strategy Strategy Strategy No. of courses No. of infectious episodes (%) No. of death (%) * p=0.984; # p=0.005 No prophylaxis 202 45 (22%) * 12 (5.94%) # Both bacterial and fungal prophylaxis 171 38 (18%) * 1 (0.58%) # Only bacterial prophylaxis 206 31 (15%) 6 (2.91%) Only fungal prophylaxis 4 0 (0%) 0 (0%)