Clinical use of voriconazole, posaconazole, and itraconazole revealed the need for therapeutic drug monitoring (TDM) of plasma concentrations of these antifungal agents. This need for TDM was not evident from clinical trials. In order to establish whether this requirement also applies to isavuconazole, we examined the plasma concentrations of 283 samples from patients receiving isavuconazole in clinical practice and compared the values with those from clinical trials. The concentration distributions from real-world use and clinical trials were nearly identical (>1 μg/ml in 90% of patients). These findings suggest that routine TDM may not be necessary for isavuconazole in most instances.
Objectives
Liposomal amphotericin B (L-AMB) and isavuconazonium sulphate are commonly used antifungal drugs to treat mucormycosis. However, the efficacy of combination therapy of L-AMB/isavuconazonium sulphate versus monotherapy is unknown. We used an immunosuppressed mouse model of pulmonary mucormycosis to compare the efficacy of L-AMB/isavuconazonium sulphate versus either drug alone.
Methods
Neutropenic mice were intratracheally infected with either Rhizopus delemar or Mucor circinelloides. Treatment with L-AMB, isavuconazonium sulphate, or a combination of both started 8 h post-infection and continued through to Day +4. Placebo mice received vehicle control. Survival to Day +21 and tissue fungal burden (by conidial equivalent using quantitative PCR) on Day +4, served as primary and secondary endpoints, respectively.
Results
For mice infected with R. delemar, L-AMB and isavuconazonium sulphate equally prolonged median survival time and enhanced survival versus placebo (an overall survival of 50% for either drug alone, versus 5% for placebo). Importantly, combination treatment resulted in an overall survival of 80%. Both antifungal drugs reduced tissue fungal burden of lungs and brain by ∼1.0–2.0 log versus placebo-treated mice. Treatment with combination therapy resulted in 2.0–3.5 log reduction in fungal burden of either organ versus placebo and 1.0 log reduction versus either drug alone. Similar treatment outcomes were obtained using mice infected with M. circinelloides.
Conclusions
The L-AMB/isavuconazonium sulphate combination demonstrated greater activity versus monotherapy in immunosuppressed mice infected with either of the two most common causes of mucormycosis. These studies warrant further investigation of L-AMB/isavuconazonium sulphate combination therapy as an optimal therapy of human mucormycosis.
BackgroundThis study assessed the non-inferiority and safety of regadenoson administration during recovery from inadequate exercise compared with administration without exercise.MethodsPatients unable to achieve adequate exercise stress were randomized to regadenoson 0.4 mg either during recovery (Ex-Reg) or 1 hour after inadequate exercise (Regadenoson) (MPI1). All patients also underwent non-exercise regadenoson MPI 1-14 days later (MPI2). The number of segments with reversible perfusion defects (RPDs) detected using single photon emission computerized tomography imaging was categorized. The primary analysis evaluated the majority agreement rate between Ex-Reg and Regadenoson groups.Results1,147 patients were randomized. The lower bound of the 95% confidence interval of the difference in agreement rates (−6%) was above the −7.5% non-inferiority margin, demonstrating non-inferiority of Ex-Reg to Regadenoson. Adverse events were numerically less with Ex-Reg (MPI1). In the Ex-Reg group, one patient developed an acute coronary syndrome and another had a myocardial infarction following regadenoson after exercise. Upon review, both had electrocardiographic changes consistent with ischemia prior to regadenoson.ConclusionsAdministering regadenoson during recovery from inadequate exercise results in comparable categorization of segments with RPDs and with careful monitoring appears to be well tolerated in patients without signs/symptoms of ischemia during exercise and recovery.Electronic Supplementary MaterialThe online version of this article (doi:10.1007/s12350-017-0813-3) contains supplementary material, which is available to authorized users.
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