Efficacy and safety of micafungin as an empirical antifungal therapy for suspected fungal infection in neutropenic patients with hematological disorders

Model-Informed Dose Justifications of Posaconazole in Japanese Patients for Prophylaxis and Treatment Against Fungal Infection

Posaconazole is a globally approved broad-spectrum triazole antifungal compound. In Japanese patients, posaconazole has identical dosing regimens as those approved globally for both tablet and intravenous formulations. This article aims to describe a model-informed approach for dose justification of posaconazole in the Japanese population as either high-risk patients with fungal infections (prophylaxis patients) or patients with fungal infections (treatment patients). A simultaneous population pharmacokinetic (PK) model for tablet and intravenous formulation was developed on the basis of a data set including Japanese data from healthy participants and treatment patients. The PK profiles and exposure distributions in Japanese patients were predicted and compared against foreign patients, that is, patients outside of Japan. Relationships between the post hoc posaconazole exposures and frequently observed clinical adverse events were evaluated. Although clinical trials for Japanese prophylaxis patients were not conducted, PK profiles in Japanese prophylaxis patients were predicted using the population PK model and demographic covariate information obtained from the published literature. Based upon the globally approved dosing regimen, posaconazole exposure distribution was predicted to be the highest in Japanese treatment patients, and generally similar between Japanese and foreign prophylaxis patients. Exposures in Japanese patients exceeded the efficacy target level (500 ng/mL). Safety profiles in Japanese treatment patients with the highest exposures were clinically acceptable without specific concerns to Japanese patients and appeared to have no relationship with posaconazole exposures. From PK, safety, and efficacy perspectives, the use of the same dosing regimen as in foreign patients was justified in Japanese prophylaxis and treatment patients.

Development of a Method of Measuring β-D-Glucan and Its Use in Preemptive Therapy for Invasive Fungal Infections

Invasive fungal infections (IFIs) are serious infections that develop in conjunction with neutropenia after chemotherapy for acute leukemia or with hematopoietic stem cell transplantation. Conventionally, empirical antifungal therapy was recommended to treat IFIs for patient safety despite a lack of evidence of fungal infections. However, many studies have indicated that antifungals were not necessary for over half of patients, and several detriments of empirical therapy were noted, e.g., antifungals caused adverse reactions, an increase in drug-resistant fungi was a possibility, and medical costs soared. β-D-glucan (BDG) is a component of clinically important fungi such as Aspergillus and Candida. The G-test was developed in Japan as a way to measure BDG in serum using a coagulation factor from the blood of the horseshoe crab. Pre-emptive antifungal therapy based upon serodiagnosis with a BDG or galactomannan assay and CT imaging has been introduced. With pre-emptive antifungal therapy, the prognosis is equivalent to that with empirical therapy, and the dose of the antifungal has been successfully reduced. Measurement of BDG has been adopted widely as a method of diagnosing IFIs and is listed in the key guidelines for fungal infections and febrile neutropenia.

Efficacy and safety of micafungin in empiric and D-index-guided early antifungal therapy for febrile neutropenia; A subgroup analysis of the CEDMIC trial

OBJECTIVES

The D-index is defined as the area over the neutrophil curve during neutropenia. The CEDMIC trial confirmed the noninferiority of D-index-guided early antifungal therapy (DET) using micafungin to empirical antifungal therapy (EAT). In this study, we evaluated the efficacy and safety of micafungin in these settings.

METHODS

From the CEDMIC trial, we extracted 67 and 113 patients who received micafungin in the DET and EAT groups, respectively. Treatment success was defined as the fulfilment of all components of a five-part composite end point. Fever resolution was evaluated at seven days after the completion of therapy.

RESULTS

The proportion of high-risk treatments including induction chemotherapy for acute leukemia and allogeneic hematopoietic stem cell transplantation was significantly higher in the DET group than in the EAT group (82.1% vs. 52.2%). The efficacy of micafungin was 68.7% (95%CI: 56.2-79.4) and 79.6% (71.0-86.6) in the DET and EAT groups, respectively. When we focused on high-risk treatments, the efficacy was 69.1% (55.2-80.9%) and 78.0% (65.3-87.7%), respectively (P = 0.30). There was no significant difference in any of the 5 components between the two groups.

CONCLUSIONS

The efficacy of micafungin in patients undergoing high-risk treatment was not strongly impaired in DET compared to that in EAT.

Invasive Aspergillosis in Hematological Patients

Invasive aspergillosis (IA) is still one of the leading causes of morbidity and mortality in hematological patients, although its outcome has been improving. Prolonged and profound neutropenia in patients receiving intensive chemotherapy for acute leukemia and stem cell transplantation is a major risk factor for IA. Allogeneic stem cell transplant recipients with graft-versus-host disease and corticosteroid use are also at high risk. Management in a protective environment with high efficiency particular air (HEPA) filter is generally recommended to prevent aspergillosis in patients with prolonged and profound neutropenia. Antifungal prophylaxis against Aspergillus species should be considered in patients with past history of aspergillosis or colonization of Aspergillus species, at facilities with high incidence of IA and those without a protective environment. Early diagnosis and prompt antifungal treatment is important to improve outcome. Imaging studies such as computed tomography and biomarkers such as galactomannan antigen and β-D-glucan are useful for early diagnosis. Empirical antifungal treatment based on persistent or recurrent fever during neutropenia despite broad-spectrum antibiotic therapy is generally recommended in high-risk patients. Alternatively, a preemptive treatment strategy has recently been proposed in the context of progress in the early diagnosis of IA based on the results of imaging studies and biomarkers. Voriconazole is recommended for initial therapy for IA. Liposomal amphotericin B is considered as alternative initial therapy. Combination antifungal therapy of echinocandin with voriconazole or liposomal amphotericin B could be a choice for refractory cases.

Efficacy and safety of micafungin versus intravenous itraconazole as empirical antifungal therapy for febrile neutropenic patients with hematological malignancies: a randomized, controlled, prospective, multicenter study

Micafungin, a clinically important echinocandin antifungal drug, needs to be investigated as empirical therapy in febrile neutropenia in comparison with azole compounds. A prospective randomized study was conducted to compare clinical outcomes between micafungin and intravenous itraconazole as an empirical therapy for febrile neutropenia in hematological malignancies. The antifungal drug (micafungin 100 mg or itraconazole 200 mg IV once daily) was given for high fever that was sustained despite the administration of appropriate antibiotics. Treatment success was determined by composite end points based on breakthrough invasive fungal infection (IFI), survival, premature discontinuation, defervescence, and treatment of baseline fungal infection. Duration of fever, hospital stay, and overall survival (OS) were studied. A total of 153 patients were randomized to receive micafungin or itraconazole. The overall success rate was 7.1 % point higher in the micafungin group (64.4 vs. 57.3 %, p = 0.404), satisfying the statistical criteria for the non-inferiority of micafungin. The duration of fever and hospital stay were significantly shorter in the micafungin group (6 vs. 7 days, p = 0.014; 22 vs. 27 days, p = 0.033, respectively). Grade 3 adverse events including hyperbilirubinemia (2 vs. 7), elevation of transaminase levels (2 vs. 4), electrolyte imbalance (1 vs. 2), atrial fibrillation (1 vs. 0), and anaphylaxis (1 vs. 0) occurred in 7 and 13 patients in the micafungin (10.4 %) and itraconazole (18.8 %) groups, respectively. Micafungin, when compared with itraconazole, had favorably comparable success rate and toxicity profiles on febrile neutropenia in patients with hematological malignancies. In addition, it showed superior effect on shortening the hospital stay.

Safety and efficacy of micafungin for prophylaxis against invasive fungal infections in Japanese patients undergoing hematopoietic stem cell transplantation: Results of a post-marketing surveillance study

Invasive fungal infections are a major cause of morbidity and mortality in patients with hematopoietic stem cell transplantation. A prospective multicenter post-marketing observational surveillance study was conducted from July 2007 to June 2010 to assess the safety and efficacy of micafungin, an echinocandin antifungal, for prophylaxis against invasive fungal infections in Japanese patients undergoing hematopoietic stem cell transplantation. Among 241 patients evaluated for safety, 143 adverse drug reactions were reported in 86 patients (35.7%), with hepatobiliary disorders the most frequently reported adverse drug reactions. The success rate for prophylaxis at the end of observation was 72.8% (131/180 patients), and the incidence of breakthrough infections was only 4.4% (8/180 patients). In conclusion, micafungin had sufficient safety and efficacy for prophylaxis against invasive fungal infections in Japanese patients with various backgrounds undergoing hematopoietic stem cell transplantation.

Primary antifungal prophylaxis with micafungin in patients with haematological malignancies: real-life data from a retrospective single-centre observational study

Mould-active antifungal prophylaxis is increasingly used in patients at risk for invasive fungal disease. Between June 2011 and June 2012, one hundred patients with various haematological malignancies at risk for invasive fungal disease received primary antifungal prophylaxis with intravenous micafungin at a daily dosage of 50 mg during neutropenia. The median number of days on micafungin prophylaxis was 14 (range, 6-48 d). The incidence of proven and probable breakthrough invasive fungal diseases (bIFDs) was 6% and 3%, respectively. There were two bloodstream infections caused by yeasts or yeast-like fungi (Candida krusei, Trichosporon asahii) in two patients during the neutropenic phase after allogeneic haematopoietic stem cell transplantation. Four proven bIFDs caused by non-Aspergillus moulds and three cases of probable pulmonary bIFDs were documented during the neutropenic phase after induction/consolidation chemotherapy for acute leukaemia. Colonisation with Candida spp. was documented in 51% of the patients with none of the isolates being in vitro micafungin resistant. Compared to a historical control, receiving primary prophylaxis with posaconazole micafungin is at least as effective in preventing IFD. In both cohorts, bIFDs were exclusively caused by emerging pathogens with a highly preserved in vitro sensitivity to amphotericin B.

Safety of high-dose micafungin for patients with hematological diseases

This study was conducted as a retrospective, observational, exploratory cohort study with the aim of elucidating the safety profile of micafungin at doses exceeding 150 mg daily. We identified adult patients with hematological diseases who had received micafungin therapy for ≥ 7 consecutive days. Twenty-six patients administered micafungin at 300 mg daily (high-dose group) were compared with 58 patients administered micafungin at 150 mg daily (standard-dose group). The most frequent adverse events (AEs) were hepatotoxicity, hypertension and diarrhea. AEs were recorded in 42 (72%) and 19 (73%) patients in the standard-dose and high-dose groups, respectively (p = 1.00). Hepatobiliary AEs were noted in 28 (48%) and 15 (58%) patients, respectively (p = 0.48). Serious AEs and resultant treatment discontinuation were infrequent. Our results suggest that micafungin was safe and well tolerated at 300 mg daily.