Search

Approved antihyperglycemic therapies for pediatric patients with T2D are currently limited to metformin (MET) and insulin. SITA is being evaluated in 3 studies in patients 10-17 years of age with T2D: SITA as initial oral therapy, MK-0431 P083; SITA as add-on to MET administered as a fixed dose combination (FDC), MK-0431A P170; and SITA as add-on to MET extended-release administered as a FDC of SITA and MET XR, MK-0431A XR P289. The studies, conducted to fulfill post-marketing requirements, and a Pediatric Investigation Plan (EU), were initiated between 2011 and 2013; enrollment completed in 2018. Study protocols were amended since initiation to accommodate regulatory agency requirements, reduce patient burden related to study conduct, and improve patient accrual. Major amendments to the protocols, their rationales, and their impacts are summarized (Table) and demonstrate the flexibility that may be required to enroll such studies. The impact on enrollment of 2 amendments common to all 3 studies were quantifiable. Of patients randomized after approval of an amendment that broadened the A1C entry criterion (from lower limit of 7.0% to 6.5%), ∼34% in P083, ∼20% in P170 and ∼20% in P289 had a baseline A1C between 6.5% and 6.9%. Of patients randomized after approval of an amendment to include patients on background insulin, 11% of patients in P083, 22% in P170, and 19% in P289 enrolled on background insulin. Disclosure R. Shankar: Employee; Spouse/Partner; AstraZeneca. Employee; Self; Merck & Co., Inc. Employee; Spouse/Partner; NGM Biopharmaceuticals. V.P. Pozharskaya: Employee; Self; Merck & Co., Inc. K. Leight: Employee; Self; Merck & Co., Inc. Stock/Shareholder; Self; Merck & Co., Inc. R.S. Newfield: Research Support; Self; Bristol-Myers Squibb Company, Daiichi Sankyo Company, Limited, Eli Lilly and Company, University of California and Rady Children's Hospital, San Diego. A. Deeb: None. R. Garcia: None. C.A. Rosario: None. C.K. Saha: Research Support; Self; Indiana University School of Medicine. N. Shehadeh: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Novo Nordisk Inc., Sanofi-Aventis. Speaker's Bureau; Self; Eli Lilly and Company, Merck Sharp & Dohme Corp. Y. Samoilova: None. S.S. Engel: Employee; Self; Merck & Co., Inc. Stock/Shareholder; Self; Merck & Co., Inc. M.Y. Jalaludin: Advisory Panel; Self; Novo Nordisk Inc. Research Support; Self; Merck Sharp & Dohme Corp., Novo Nordisk Inc. P. Zeitler: Consultant; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Janssen Research & Development, Merck & Co., Inc., Novo Nordisk Inc. K.D. Kaufman: Employee; Self; Merck & Co., Inc. Stock/Shareholder; Self; Merck & Co., Inc. Funding Merck & Co., Inc.

Human herpesvirus-8 (HHV-8) is aetiologically linked to Kaposi's sarcoma and primary effusion lymphoma. Although interferon-α(IFN-α) and interferon-γ(IFN-γ) are both antiviral cytokines, IFN-αblocks entry of HHV-8 into the lytic phase, whereas IFN-γinduces an increase in the percentage of cells undergoing lytic replication. Multiple events in the lytic cascade must be completed to produce infectious virus. The ability of both types of IFN to affect the production of infectious virus was explored. Both IFN-αand IFN-γinduced expression of the antiviral proteins double-stranded RNA-activated protein kinase (PKR) and 2′5′-oligoadenylate synthetase (2′5′-OAS) in HHV-8-infected BCBL-1 cells. Higher levels resulted from incubation with IFN-αthan with IFN-γ, whereas IFN-γinduced higher levels of IRF-1 than did IFN-α. IFN-γinduced a minor increase in lytic viral gene expression, which was not accompanied by a detectible increase in infectious virus. When lytic replication of HHV-8 was induced using TPA, high levels of infectious virus appeared in the conditioned medium. When IFN-γwas present during TPA stimulation, the production of infectious virus was reduced by at least a 60 %, and IFN-αfully blocked TPA-induced production of infectious virus. The greater reduction of viral production that occurred with IFN-αis consistent with the higher levels of the antiviral proteins PKR and 2′5′-OAS induced by IFN-αthan by IFN-γ. These studies indicate that the augmentation of cellular antiviral defences by IFN-γwas sufficient to prevent production of infectious virus despite IFN-γ-induced entry of some cells into the lytic phase of HHV-8 replication.

Human herpesvirus 8 (HHV-8) encodes multiple proteins that disrupt the host antiviral response, including viral interferon (IFN) regulatory factor 1 (vIRF-1). The product of the vIRF-1 gene blocks responses to IFN when overexpressed by transfection, but the functional consequence of vIRF-1 that is expressed during infection with HHV-8 is not known. These studies demonstrate that BCBL-1 cells that were latently infected with HHV-8 expressed low levels of vIRF-1 that were associated with PML bodies, whereas much higher levels of vIRF-1 were transiently expressed during the lytic phase of HHV-8 replication. The low levels of vIRF-1 that were associated with PML bodies were insufficient to block alpha IFN (IFN-α)-induced alterations in gene expression, whereas cells that expressed high levels of vIRF-1 were resistant to some changes induced by IFN-α, including the expression of the double-stranded-RNA-activated protein kinase. High levels of vIRF-1 were expressed for only a short period during the lytic cascade, so many cells with HHV-8 in the lytic phase responded to IFN-α with increased expression of antiviral genes and enhanced apoptosis. Furthermore, the production of infectious virus was severely compromised when IFN-α was present early during the lytic cascade. These studies indicate that the transient expression of high levels of vIRF-1 is inadequate to subvert many of the antiviral effects of IFN-α so that IFN-α can effectively induce apoptosis and block production of infectious virus when present early in the lytic cascade of HHV-8.

Background Several studies have implicated viral infection as an important factor in the pathogenesis of IPF and related fibrotic lung disorders. Viruses are thought to cause epithelial cell injury and promote epithelial-mesenchymal transition (EMT), a process whereby differentiated epithelial cells undergo transition to a mesenchymal phenotype, and considered a source of fibroblasts in the setting of lung injury. We have demonstrated an association between the epithelial injury caused by chronic herpes virus infection with the murine gamma-herpes virus, MHV68, and lung fibrosis. We hypothesize that EMT in this model of virus-induced pulmonary fibrosis is driven by the expression of the transcription factor Twist. Methods/findings In vitro MHV68 infection of murine lung epithelial cells induced expression of Twist, and mesenchymal markers. Stable overexpression of Twist promoted EMT in MLE15 lung epithelial cells. Transient knockdown expression of Twist resulted in preservation of epithelial phenotype after in vitro MHV68 infection. In concordance, high expression of Twist was found in lung epithelial cells of MHV68 infected mice, but not in mock infected mice. Alveolar epithelial cells from lung tissue of idiopathic pulmonary fibrosis (IPF) patients were strongly positive for Twist. These cells demonstrated features of EMT with low expression of E-cadherin and upregulation of the mesenchymal marker N-cadherin. Finally, IPF tissue with high Twist protein levels was also positive for the herpesvirus, EBV. Conclusions/significance We conclude that Twist contributes to EMT in the model of virus-induced pulmonary fibrosis. We speculate that in some IPF cases, gamma-herpes virus infection with EBV might be a source of injury precipitating EMT through the expression of Twist.

Primary effusion lymphoma (PEL) is a B-cell lymphoma in which human herpesvirus-8 (HHV-8) is found within all tumor cells and represents a target for selectively destroying tumor cells. HHV-8 is latent in most PEL cells and, hence, resistant to antiviral agents that inhibit lytic replication. We demonstrate that PEL cell lines containing HHV-8 without and with coinfection with Epstein-Barr virus responded to the antiseizure medication valproate with entry into the lytic cascade and production of infectious virus. Minimal cell death occurred when noninfected BL-41 cells were incubated with valproate, whereas apoptosis occurred in response to valproate in PELs that supported lytic replication of HHV-8. The anti-viral agents ganciclovir and phosphonoformic acid (PFA) blocked valproate-induced production of infectious virus without blocking entry into the lytic cascade, and apoptosis occurred at levels that were as high as when virus production was not blocked. Ganciclovir and PFA also prevented most valproate-induced expression of the late lytic viral transcript open reading frame 26 (ORF-26), but they did not block the induction of either viral interleukin-6 (vIL-6) or viral G protein-coupled receptor (vGPCR). These studies provide evidence that incubation of PELs with valproate in the presence of ganciclovir or PFA can selectively target tumor cells for apoptosis without increasing viral load.

Infection of endothelial cells with human herpesvirus 8 (HHV-8) is an essential event in the development of Kaposi's sarcoma. When primary microvascular endothelial cells (MECs) were infected with HHV-8 at a low multiplicity of infection, considerable latent replication of HHV-8 occurred, leading to a time-dependent increase in the percentage of virus-infected cells that was accompanied by cellular spindling and growth to a high density with loss of contact inhibition. Only a low percentage of MECs supported lytic replication of HHV-8 and produced infectious virus. Phosphonoformic acid blocked production of infectious virus but did not inhibit the rapid expansion of latently infected MECs. Pretreatment of MECs with alpha interferon (IFN-α) prior to infection effectively reduced HHV-8 viral gene expression, latent replication, and production of infectious virus. High levels of the double-stranded RNA activated protein kinase (PKR) were expressed in HHV-8-infected cells, and incubation with IFN-α increased PKR expression more in virus-infected cells than in uninfected cells. MECs that were immortalized with simian virus 40 large-T antigen differed from nonimmortalized MECs in their response to infection with HHV-8 and demonstrated that cells with elevated levels of expression of antiviral transcripts expressed viral transcripts at reduced levels. These studies demonstrate that MECs respond to HHV-8 with enhanced expression of cellular antiviral genes and that augmentation of innate antiviral defenses with IFN-α is a more effective strategy than inhibition of viral lytic replication to protect MECs from infection with HHV-8 and to restrict proliferation of virus-infected MECs.