Cytomegalovirus (CMV) infection and disease are important causes of morbidity and mortality among transplant recipients. For the purpose of developing consistent reporting of CMV in clinical trials, definitions of CMV infection and disease were developed and published. This study seeks to update the definitions of CMV on the basis of recent developments in diagnostic techniques, as well as to add to these definitions the concept of indirect effects caused by CMV.

Cytomegalovirus (CMV) infection and disease are important causes of morbidity and mortality in transplant recipients. For the purpose of developing consistent reporting of CMV outcomes in clinical trials, definitions of CMV infection and disease were developed and most recently published in 2002. Since then, there have been major developments in its diagnosis and management. Therefore, the CMV Drug Development Forum consisting of scientists, clinicians, regulators, and industry representatives has produced an updated version incorporating recent knowledge with the aim to support clinical research and drug development. The main changes compared to previous definitions are the introduction of a "probable disease" category and to incorporate quantitative nucleic acid testing in some end-organ disease categories. As the field evolves, the need for updates of these definitions is clear, and collaborative efforts between scientists, regulators, and industry can provide a platform for this work.

The genetic content of wild-type human cytomegalovirus was investigated by sequencing the 235 645 bp genome of a low passage strain (Merlin). Substantial regions of the genome (genes RL1-UL11, UL105-UL112 and UL120-UL150) were also sequenced in several other strains, including two that had not been passaged in cell culture. Comparative analyses, which employed the published genome sequence of a high passage strain (AD169), indicated that Merlin accurately reflects the wild-type complement of 165 genes, containing no obvious mutations other than a single nucleotide substitution that truncates gene UL128. A sizeable subset of genes exhibits unusually high variation between strains, and comprises many, but not all, of those that encode proteins known or predicted to be secreted or membrane-associated. In contrast to unpassaged strains, all of the passaged strains analysed have visibly disabling mutations in one or both of two groups of genes that may influence cell tropism. One comprises UL128, UL130 and UL131A, which putatively encode secreted proteins, and the other contains RL5A, RL13 and UL9, which are members of the RL11 glycoprotein gene family. The case in support of a lack of protein-coding potential in the region between UL105 and UL111A was also strengthened.

BACKGROUND The treatment of symptomatic congenital cytomegalovirus (CMV) disease with intravenous ganciclovir for 6 weeks has been shown to improve audiologic outcomes at 6 months, but the benefits wane over time. METHODS We conducted a randomized, placebo-controlled trial of valganciclovir therapy in neonates with symptomatic congenital CMV disease, comparing 6 months of therapy with 6 weeks of therapy. The primary end point was the change in hearing in the better ear (“best-ear” hearing) from baseline to 6 months. Secondary end points included the change in hearing from baseline to follow-up at 12 and 24 months and neurodevelopmental outcomes, with each end point adjusted for central nervous system involvement at baseline. RESULTS A total of 96 neonates underwent randomization, of whom 86 had follow-up data at 6 months that could be evaluated. Best-ear hearing at 6 months was similar in the 6-month group and the 6-week group (2 and 3 participants, respectively, had improvement; 36 and 37 had no change; and 5 and 3 had worsening; P = 0.41). Total-ear hearing (hearing in one or both ears that could be evaluated) was more likely to be improved or to remain normal at 12 months in the 6-month group than in the 6-week group (73% vs. 57%, P = 0.01). The benefit in total-ear hearing was maintained at 24 months (77% vs. 64%, P = 0.04). At 24 months, the 6-month group, as compared with the 6-week group, had better neurodevelopmental scores on the Bayley Scales of Infant and Toddler Development, third edition, on the language-composite component (P = 0.004) and on the receptive-communication scale (P = 0.003). Grade 3 or 4 neutropenia occurred in 19% of the participants during the first 6 weeks. During the next 4.5 months of the study, grade 3 or 4 neutropenia occurred in 21% of the participants in the 6-month group and in 27% of those in the 6-week group (P = 0.64). CONCLUSIONS Treating symptomatic congenital CMV disease with valganciclovir for 6 months, as compared with 6 weeks, did not improve hearing in the short term but appeared to improve hearing and developmental outcomes modestly in the longer term. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT00466817.)