rupintrivir and Common-Cold

The common cold is an important illness both as a result of the economic impact of this common disease and because of the morbidity associated with the complications of the illness. Recent attempts to develop antiviral treatments for the common cold represent a substantial advance over previous efforts. Formidable barriers remain to be overcome, however, before any of these new products will be proven to be clinically useful. Recent advances in our understanding of the pathogenesis of common cold symptoms have provided insights into potential new targets for the treatment of this illness.

Topics: 3C Viral Proteases; Antiviral Agents; Clinical Trials as Topic; Combined Modality Therapy; Common Cold; Cysteine Endopeptidases; Dietary Supplements; Drug Therapy, Combination; Echinacea; Enzyme Inhibitors; Histamine H1 Antagonists; Humans; Intercellular Adhesion Molecule-1; Isoxazoles; Oxadiazoles; Oxazoles; Phenylalanine; Phytotherapy; Picornaviridae Infections; Plant Extracts; Plants, Medicinal; Pyrrolidinones; Receptors, Virus; Rhinovirus; Valine; Viral Proteins; Zinc

Human rhinovirus (HRV) infections are usually self-limited but may be associated with serious consequences, particularly in those with asthma and chronic respiratory disease. Effective antiviral agents are needed for preventing and treating HRV illnesses. Ruprintrivir (Agouron Pharmaceuticals, Inc., San Diego, Calif.) selectively inhibits HRV 3C protease and shows potent, broad-spectrum anti-HRV activity in vitro. We conducted three double-blind, placebo-controlled clinical trials in 202 healthy volunteers to assess the activity of ruprintrivir in experimental HRV infection. Subjects were randomized to receive intranasal ruprintrivir (8 mg) or placebo sprays as prophylaxis (two or five times daily [2x/day or 5x/day] for 5 days) starting 6 h before infection or as treatment (5x/day for 4 days) starting 24 h after infection. Ruprintrivir prophylaxis reduced the proportion of subjects with positive viral cultures (for 5x/day dosing groups, 44% for ruprintrivir treatment group versus 70% for placebo treatment group [P=0.03]; for 2x/day dosing groups, 60% for ruprintrivir group versus 92% for placebo group [P=0.004]) and viral titers but did not decrease the frequency of colds. Ruprintrivir treatment reduced the mean total daily symptom score (2.2 for ruprintrivir treatment group and 3.3 for the placebo treatment group [P=0.014]) by 33%. Secondary endpoints, including viral titers, individual symptom scores, and nasal discharge weights, were also reduced by ruprintrivir treatment. Overall, ruprintrivir was well tolerated; blood-tinged mucus and nasal passage irritation were the most common adverse effects reported. Pharmacokinetic analysis of plasma and nasal ruprintrivir concentrations revealed intranasal drug residence with minimal systemic absorption. Results from these studies in experimental rhinoviral infection support continued investigation of intranasal ruprintrivir in the setting of natural HRV infection.

Topics: Administration, Inhalation; Adolescent; Adult; Antiviral Agents; Biological Availability; Common Cold; Double-Blind Method; Endpoint Determination; Female; Humans; Isoxazoles; Male; Middle Aged; Mucus; Oxazoles; Phenylalanine; Pyrrolidines; Pyrrolidinones; Rhinovirus; Suspensions; Valine

Human rhinovirus type C (HRV-C) is a newly discovered enterovirus species frequently associated with exacerbation of asthma and other acute respiratory conditions. Until recently, HRV-C could not be propagated in vitro, hampering in-depth characterization of the virus replication cycle and preventing efficient testing of antiviral agents. Herein we describe several subgenomic RNA replicon systems and a cell culture infectious model for HRV-C that can be used for antiviral screening. The replicon constructs consist of genome sequences from HRVc15, HRVc11, HRVc24, and HRVc25 strains, with the P1 capsid region replaced by a Renilla luciferase coding sequence. Following transfection of the replicon RNA into HeLa cells, the constructs produced time-dependent increases in luciferase signal that can be inhibited in a dose-dependent manner by known inhibitors of HRV replication, including the 3C protease inhibitor rupintrivir, the nucleoside analog inhibitor MK-0608, and the phosphatidylinositol 4-kinase IIIβ (PI4K-IIIβ) kinase inhibitor PIK93. Furthermore, with the exception of pleconaril and pirodavir, the other tested classes of HRV inhibitors blocked the replication of full-length HRVc15 and HRVc11 in human airway epithelial cells (HAEs) that were differentiated in the air-liquid interface, exhibiting antiviral activities similar to those observed with HRV-16. In summary, this study is the first comprehensive profiling of multiple classes of antivirals against HRV-C, and the set of newly developed quantitative HRV-C antiviral assays represent indispensable tools for the identification and evaluation of novel panserotype HRV inhibitors.

Topics: Antiviral Agents; Common Cold; Dose-Response Relationship, Drug; HeLa Cells; Humans; In Vitro Techniques; Isoxazoles; Oxadiazoles; Oxazoles; Phenylalanine; Piperidines; Pyridazines; Pyrrolidinones; Replicon; Rhinovirus; RNA, Viral; Tubercidin; Valine; Virus Replication

Human Rhinovirus (HRV) is the most important aetiologic agent of common cold in adults and children. HRV is a single-stranded, positive sense RNA virus and, despite the high level of conservation among different serotypes, sequence alignment of viral protease 3C with mammalian protease reveals no homology. Thus, protease 3C is an optimal target for the development of anti-HRV agents. In the present work we investigated the design, the synthesis and the development of new potential reversible inhibitors against HRV protease 3C. Docking studies on the crystallized structure of HRV2 protease 3C led us to the design and the synthesis of a series of 3,5 disubstituted benzamides able to act as analogues of the substrate. We also developed 1,3,5 trisubstituted benzamides where aromatic substitutions on the aryl ring led us to investigate the importance of pi-pi interaction on the stabilization of protease 3C-inhibitor complex. All structures were tested for enzymatic inhibition on HRV14 protease 3C. Results highlighted the inhibitory activity of compounds 13, 14, and 20 (91%, 81%, and 85% at 10 microM, respectively), with the latter exhibiting an ID(50) (dose that inhibits 50% of the viral cytopathic effect) on HRV-14=25 microg/ml.

Topics: 3C Viral Proteases; Antiviral Agents; Benzamides; Common Cold; Cysteine Endopeptidases; Cysteine Proteinase Inhibitors; Humans; Inhibitory Concentration 50; Rhinovirus; Structure-Activity Relationship; Viral Proteins

We tested the in vitro activity of pleconaril and AG7088 against five numbered human rhinovirus (HRV) serotypes and 46 clinical HRV isolates of undefined serotype recovered from patients with common colds. Antiviral effect of pleconaril and AG7088 were assessed by cytophathic effect (CPE) inhibition assays in Ohio HeLaI cells using microscopic and spectrophotometric methods. Both compounds were tested at concentrations of 1.0, 0.1 and 0.01 microg/ml. For the numbered HRV serotypes, the median EC(50) value determined by the microscopic CPE inhibition was slightly better for AG7088 compared to pleconaril (P=0.02) but was similar by spectrophotometric assay (P=0.15). For clinical HRV isolates the median EC(50) value determined microscopically was 0.01 microg/ml range, <0.01-0.04 microg/ml) for AG7088 compared to 0.07 microg/ml (range, <0.01->1 microg/ml) for pleconaril (P<0.001). The median EC(50) value determined by spectrophotometric assay was 0.01 microg/ml (range, <0.01-0.04 microg/ml) for AG7088 compared to 0.04 microg/ml (range, <0.01->1 microg/ml) for pleconaril (P<0.001). By either the microscopic or spectrophotometric methods the median EC(50) value of AG7088 was <1.0 microg/ml for all isolates and was >10.0 microg/ml of pleconaril for approximately 9% of isolates. In vitro AG7088 appeared to be more potent and to have a broader antirhinoviral spectrum than pleconaril among clinical HRV isolates. The clinical relevance of these in vitro results needs to be determined in controlled clinical trials.

Topics: Antiviral Agents; Cell Survival; Cells, Cultured; Common Cold; Humans; Isoxazoles; Oxadiazoles; Oxazoles; Phenylalanine; Pyrrolidinones; Reverse Transcriptase Polymerase Chain Reaction; Rhinovirus; Spectrophotometry; Valine