A quantitative LC-MS/MS method for the determination of tissue brincidofovir and cidofovir diphosphate in a MuPyV-infected mouse model

Brincidofovir (BCV) is an investigational lipid conjugate of the nucleotide analog cidofovir (CDV), which is being developed as a medical countermeasure for the treatment of smallpox. BCV is active against double-stranded DNA viruses including BK and JC viruses. Here, we validated procedures for quantifying BCV and its pharmacologically active moiety cidofovir diphosphate (CDV-PP) in mouse kidney, brain and spleen tissue homogenates. Following homogenization, BCV and CDV-PP were extracted from the tissues by protein precipitation with their stable, isotopically labeled internal standards, BCV-d₆ and ¹³ C₃ ¹⁵ N₂ -CDV-PP. Then, samples were analyzed for BCV by reverse-phase chromatography on a Waters Xterra MS C₁₈ (50 × 2.1 mm, 3.5 μm particle size) column while CDV-PP was analyzed on a Thermo BioBasic AX (50 × 2.1 mm, 5 μm particle size) column using anion exchange chromatography. Detection was achieved by electrospray ionization in positive ion mode on an AB Sciex API-5000 triple quadrupole mass spectrometer. The calibration curves were linear over a range of 1.00-1,000 ng/ml homogenate and 0.050-50.0 ng/ml homogenate for BCV and CDV-PP, respectively. These methods were validated according to US Food and Drug Administration guidance for industry and may be used to characterize the tissue pharmacology of both analytes to advance its preclinical development.

Respiratory viruses in transplant recipients: more than just a cold. Clinical syndromes and infection prevention principles

OBJECTIVES

The aim of this review is to provide updated information on the clinical spectrum, treatment options, and infection prevention strategies for respiratory viral infections (RVIs) in both solid organ (SOT) and hematopoietic stem cell transplant (HSCT) patients.

METHODS

The MEDLINE and PubMed databases were searched for literature regarding the aforementioned aspects of RVIs, with focus on respiratory syncytial virus, adenovirus, influenza virus, parainfluenza virus, human metapneumovirus, and rhinovirus.

RESULTS

Compared to immunocompetent hosts, SOT and HSCT patients are much more likely to experience a prolonged duration of illness, prolonged shedding, and progression of upper respiratory tract disease to pneumonia when infected with respiratory viruses. Adenovirus and respiratory syncytial virus tend to have the highest mortality and risk for disseminated disease, but all the RVIs are associated with higher morbidity and mortality in these patients than in the general population. These viruses are spread via direct contact and aerosolized droplets, and nosocomial spread has been reported.

CONCLUSIONS

RVIs are associated with high morbidity and mortality among SOT and HSCT recipients. Management options are currently limited or lack strong clinical evidence. As community and nosocomial spread has been reported for all reviewed RVIs, strict adherence to infection control measures is key to preventing outbreaks.

Update in the treatment of non-influenza respiratory virus infection in solid organ transplant recipients

INTRODUCTION

Despite the improved outcomes in solid organ transplantation with regard to prevention of rejection and increased patient and graft survival, infection remains a common cause of morbidity and mortality. Respiratory viruses are a frequent and potentially serious cause of infection after solid organ transplantation. Furthermore, clinical manifestations of respiratory virus infection (RVI) may be more severe and unusual in solid organ transplant recipients (SOTRs) compared with the non-immunocompromised population. Areas covered: This article reviews the non-influenza RVIs that are commonly encountered in SOTRs. Epidemiologic and clinical characteristics are highlighted and available treatment options are discussed. Expert opinion: New diagnostic tools, particularly rapid molecular assays, have expanded the ability to identify specific RVI pathogens in SOTRs. This is not only useful from a treatment standpoint but also to guide infection control practices. More data are needed on RVIs in the solid organ transplant population, particularly regarding their effect on rejection and graft dysfunction. There is also a need for new antiviral agents active against these infections as well as markers that can identify which patients would most benefit from treatment.