Posaconazole vs Standard Azole (FLU/ITRA) Therapy for Prophylaxis of Invasive Fungal Infections (IFIs) among High-Risk Neutropenic Patients: Results of a Randomized, Multicenter Trial.

Background: Patients with severe and prolonged neutropenia are at high-risk of developing life-threatening IFIs. Despite current treatment option, IFIs are difficult to treat and frequently associated with high mortality rates. Antifungal prophylaxis has shown benefits in high-risk populations and is a standard practice in many institutions. We compared Posaconazole (POS), a new broad-spectrum triazole, vs Standard Azoles for the prevention of IFIs in patients with a new diagnosis or first relapse of acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) being treated with intensive chemotherapy.

Methods: Patients in this randomized, evaluator-blinded, active controlled, multi-center study received oral POS (200mg tid) or oral Standard Azoles (either Fluconazole [FLU 400mg qd] or Itraconazole solution [ITRA 200mg bid]) with each cycle of chemotherapy until complete remission or for up to a maximum of 12 weeks. The primary efficacy end point was the comparison of the incidence of IFIs during the treatment phase (7 days after last dose) as adjudicated by the blinded expert panel based on EORTC/MSG criteria. The incidence of IFIs 100 days after randomization and the clinical outcome at the end of the treatment phase were also compared. Treatment failure was defined as presence of proven or probable IFIs, use of >3 days of empirical systemic antifungal treatment, use of >3 consecutive days or a total of 10 or more days of IV study drug (or alternative formulation for POS), discontinuation due to an adverse event related to study drug or lost to follow-up during treatment.

Results: 602 patients were enrolled (304 POS, 298 Standard Azole [240 FLU, 58 ITRA]). The incidence of proven/probable IFIs was lower with POS prophylaxis (see table). The overall mortality was 49 (16%) vs 67 (22%) for patients in the POS and Standard Azoles arms respectively. Analysis of time to death (all cause mortality) within 100 days post randomization yielded a P-value of 0.035, indicating a significant survival benefit in favor of POS. Twenty-one (21) deaths due to IFIs occurred during the study (POS 5, Standard Azoles 16, P = 0.012). Treatment failures were fewer in the POS arm vs Standard Azoles arm (36% vs 46%, P = 0.0091). Safety and tolerability were comparable.

Conclusions: In this study, POS was superior to the use of a Standard Azoles (FLU or ITRA) in preventing IFIs and in preventing aspergillosis, in high-risk neutropenic patients with AML or MDS undergoing intensive chemotherapy. Patients receiving POS experienced a significant survival benefit.