RESUMEN
Adenovirus infections of immunocompromised patients can cause life-threatening disseminated disease. While there are presently no drugs specifically approved to treat these infections, there are several compounds that showed efficacy against adenovirus in preclinical studies. For any such compound, low toxicity is an essential requirement. As cumulative drug effects can accentuate pathology, especially in patients with other morbidities, it is important to limit antiviral exposure to what is absolutely necessary. This is achievable by monitoring the virus burden of the patients and administering antivirals to suppress virus replication to a non-pathogenic level. We modeled such a system using Syrian hamsters infected with a replication-competent adenovirus vector, in which luciferase expression is coupled to virus replication. We found that virus replication could be followed in vivo in the same animal by repeated measurement of luciferase expression. To test the utility of an interrupted treatment regimen, we used NPP-669 and valganciclovir, two antiviral compounds with high and moderate anti-adenoviral efficacy, respectively. We found that short-term treatment of adenovirus-infected hamsters at times of peak virus replication can prevent virus-associated pathology. Thus, we believe that this animal model can be used to model different treatment regimens for anti-adenoviral compounds.
Asunto(s)
Infecciones por Adenoviridae , Adenoviridae , Antivirales , Modelos Animales de Enfermedad , Mesocricetus , Replicación Viral , Animales , Antivirales/farmacología , Antivirales/uso terapéutico , Replicación Viral/efectos de los fármacos , Infecciones por Adenoviridae/tratamiento farmacológico , Infecciones por Adenoviridae/virología , Cricetinae , Adenoviridae/efectos de los fármacos , Adenoviridae/fisiología , Carga Viral/efectos de los fármacos , Humanos , Estudios LongitudinalesRESUMEN
Human adenoviruses can cause serious, disseminated infections in immunocompromised patients. For pediatric allogeneic stem cell transplant patients, the case fatality rate can reach 80%. Still, there is no available antiviral drug that is specifically approved by the Food and Drug Administration for the treatment of adenovirus infections. To fill this pressing medical need, we have developed NPP-669, a prodrug of cidofovir with broad activity against double-stranded DNA viruses, including adenoviruses. Here, we report on the in vivo anti-adenoviral efficacy of NPP-669. Using the immunosuppressed Syrian hamster as the model, we show that NPP-669 is highly efficacious when dosed orally at 1 mg/kg and 3 mg/kg. In a delayed administration experiment, NPP-669 was more effective than brincidofovir, a similar compound that reached Phase III clinical trials. Furthermore, parenteral administration of NPP-669 increased its efficacy approximately 10-fold compared to oral dosing without apparent toxicity, suggesting that this route may be preferable in a hospital setting. Based on these findings, we believe that NPP-669 is a promising new compound that needs to be further investigated.
Asunto(s)
Antivirales , Cidofovir , Citosina , Mesocricetus , Organofosfonatos , Profármacos , Animales , Antivirales/farmacología , Antivirales/uso terapéutico , Profármacos/farmacología , Profármacos/uso terapéutico , Humanos , Cidofovir/farmacología , Cidofovir/uso terapéutico , Organofosfonatos/farmacología , Organofosfonatos/uso terapéutico , Citosina/análogos & derivados , Citosina/farmacología , Citosina/uso terapéutico , Adenovirus Humanos/efectos de los fármacos , Infecciones por Adenovirus Humanos/tratamiento farmacológico , Infecciones por Adenovirus Humanos/virología , Modelos Animales de Enfermedad , Cricetinae , Administración OralRESUMEN
Seasonal influenza virus infections cause a substantial number of deaths each year. While zanamivir (ZAN) is efficacious against oseltamivir-resistant influenza strains, the efficacy of the drug is limited by its route of administration, oral inhalation. Herein, we present the development of a hydrogel-forming microneedle array (MA) in combination with ZAN reservoirs for treating seasonal influenza. The MA was fabricated from Gantrez® S-97 crosslinked with PEG 10,000. Various reservoir formulations included ZAN hydrate, ZAN hydrochloric acid (HCl), CarraDres™, gelatin, trehalose, and/or alginate. In vitro permeation studies with a lyophilized reservoir consisting of ZAN HCl, gelatin, and trehalose resulted in rapid and high delivery of up to 33 mg of ZAN across the skin with delivery efficiency of up to ≈75% by 24 h. Pharmacokinetics studies in rats and pigs demonstrated that a single administration of a MA in combination with a CarraDres™ ZAN HCl reservoir offered a simple and minimally invasive delivery of ZAN into the systemic circulation. In pigs, efficacious plasma and lung steady-state levels of â¼120 ng/mL were reached within 2 h and sustained between 50 and 250 ng/mL over 5 days. MA-enabled delivery of ZAN could enable a larger number of patients to be reached during an influenza outbreak.
Asunto(s)
Gripe Humana , Zanamivir , Ratas , Animales , Porcinos , Humanos , Zanamivir/uso terapéutico , Antivirales , Gelatina , TrehalosaRESUMEN
DNA viruses are responsible for many diseases in humans. Current treatments are often limited by toxicity, as in the case of cidofovir (CDV, Vistide), a compound used against cytomegalovirus (CMV) and adenovirus (AdV) infections. CDV is a polar molecule with poor bioavailability, and its overall clinical utility is limited by the high occurrence of acute nephrotoxicity. To circumvent these disadvantages, we designed nine CDV prodrug analogues. The prodrugs modulate the polarity of CDV with a long sulfonyl alkyl chain attached to one of the phosphono oxygens. We added capping groups to the end of the alkyl chain to minimize ß-oxidation and focus the metabolism on the phosphoester hydrolysis, thereby tuning the rate of this reaction by altering the alkyl chain length. With these modifications, the prodrugs have excellent aqueous solubility, optimized metabolic stability, increased cellular permeability, and rapid intracellular conversion to the pharmacologically active diphosphate form (CDV-PP). The prodrugs exhibited significantly enhanced antiviral potency against a wide range of DNA viruses in infected human foreskin fibroblasts. Single-dose intravenous and oral pharmacokinetic experiments showed that the compounds maintained plasma and target tissue levels of CDV well above the EC50 for 24 h. These experiments identified a novel lead candidate, NPP-669. NPP-669 demonstrated efficacy against CMV infections in mice and AdV infections in hamsters following oral (p.o.) dosing at a dose of 1 mg/kg BID and 0.1 mg/kg QD, respectively. We further showed that NPP-669 at 30 mg/kg QD did not exhibit histological signs of toxicity in mice or hamsters. These data suggest that NPP-669 is a promising lead candidate for a broad-spectrum antiviral compound.
Asunto(s)
Infecciones por Citomegalovirus , Organofosfonatos , Profármacos , Ratones , Humanos , Animales , Antivirales/farmacocinética , Disponibilidad Biológica , Profármacos/farmacología , Citosina , CidofovirRESUMEN
PURPOSE: Amifostine (AMF), a radioprotectant, is FDA-approved for intravenous administration in cancer patients receiving radiation therapy (XRT). Unfortunately, it remains clinically underutilized due to adverse side effects. The purpose of this study is to define the pharmacokinetic profile of an oral AMF formulation potentially capable of reducing side effects and increasing clinical feasibility. METHODS: Calvarial osteoblasts were radiated under three conditions: no drug, AMF, and WR-1065 (active metabolite). Osteogenic potential of cells was measured using alkaline phosphatase staining. Next, rats were given AMF intravenously or directly into the jejunum, and pharmacokinetic profiles were evaluated. Finally, rats were given AMF orally or subcutaneously, and blood samples were analyzed for pharmacokinetics. RESULTS: WR-1065 preserved osteogenic potential of calvarial osteoblasts after XRT to a greater degree than AMF. Direct jejunal AMF administration incurred a systemic bioavailability of 61.5%. Subcutaneously administrated AMF yielded higher systemic levels, a more rapid peak exposure (0.438 vs. 0.875 h), and greater total systemic exposure of WR-1065 (116,756 vs. 16,874 ng*hr/ml) compared to orally administered AMF. CONCLUSIONS: Orally administered AMF achieves a similar systemic bioavailability and decreased peak plasma level of WR-1065 compared to intravenously administered AMF, suggesting oral AMF formulations maintain radioprotective efficacy without causing onerous side effects, and are clinically feasible.
Asunto(s)
Amifostina/farmacocinética , Mercaptoetilaminas/farmacocinética , Osteogénesis/efectos de los fármacos , Traumatismos Experimentales por Radiación/prevención & control , Protectores contra Radiación/farmacocinética , Administración Intravenosa , Administración Oral , Amifostina/administración & dosificación , Animales , Disponibilidad Biológica , Línea Celular , Neoplasias de Cabeza y Cuello/radioterapia , Humanos , Inyecciones Subcutáneas , Yeyuno/efectos de los fármacos , Yeyuno/metabolismo , Yeyuno/efectos de la radiación , Masculino , Mercaptoetilaminas/administración & dosificación , Osteoblastos/efectos de los fármacos , Osteoblastos/efectos de la radiación , Osteogénesis/efectos de la radiación , Traumatismos Experimentales por Radiación/etiología , Protectores contra Radiación/administración & dosificación , Ratas , Cráneo/citología , Resultado del TratamientoRESUMEN
Human adenoviruses (AdV) cause generally mild infections of the respiratory and GI tracts as well as some other tissues. However, AdV can cause serious infection in severely immunosuppressed individuals, especially pediatric patients undergoing allogeneic hematopoietic stem cell transplantation, where mortality rates are up to 80% with disseminated disease. Despite the seriousness of AdV disease, there are no drugs approved specifically to treat AdV infections. We report here that USC-087, an N-alkyl tyrosinamide phosphonate ester prodrug of HPMPA, the adenine analog of cidofovir, is highly effective against multiple AdV types in cell culture. USC-087 is also effective against AdV-C6 in our immunosuppressed permissive Syrian hamster model. In this model, hamsters are immunosuppressed by treatment with high dose cyclophosphamide. Injection of AdV-C6 (or AdV-C5) intravenously leads to a disseminated infection that resembles the disease seen in humans, including death. We have tested the efficacy of orally-administered USC-087 against the median lethal dose of intravenously administered AdV-C6. USC-087 completely prevented or significantly decreased mortality when administered up to 4 days post challenge. USC-087 also prevented or significantly decreased liver damage caused by AdV-C6 infection, and suppressed virus replication even when administered 4 days post challenge. These results imply that USC-087 is a promising candidate for drug development against HAdV infections.
Asunto(s)
Adenina/análogos & derivados , Infecciones por Adenovirus Humanos/tratamiento farmacológico , Adenovirus Humanos/efectos de los fármacos , Antivirales/administración & dosificación , Organofosfonatos/administración & dosificación , Profármacos/administración & dosificación , Tirosina/análogos & derivados , Adenina/administración & dosificación , Administración Oral , Animales , Modelos Animales de Enfermedad , Huésped Inmunocomprometido , Hígado/patología , Mesocricetus , Análisis de Supervivencia , Resultado del Tratamiento , Tirosina/administración & dosificaciónRESUMEN
Hypotension is the dose-limiting side effect of the radio-protective drug Amifostine and results from relaxation of the vascular smooth muscle, which is directly mediated by the active metabolite, WR-1065, of Amifostine. The route of administration (currently FDA-approved only for intravenous administration) and the rapid metabolic conversion of Amifostine combine to yield high systemic levels of WR-1065 and facilitate the onset of hypotension. Research efforts aiming to optimize the delivery of WR-1065 to maintain efficacy while reducing its peak, systemic concentration below levels that induce hypotension are underway. To fully characterize the effect of reduced dose levels and alternative routes of administration of Amifostine on systemic WR-1065 concentrations, improved analytical techniques are needed. We have developed and evaluated a highly sensitive method for measuring WR-1065 in rat plasma that employs chemical derivatization, protein precipitation and UPLC-MS/MS analysis. The method exhibits a limit of quantification (LOQ) of 7.4â¯nM in plasma, which is a significant improvement over conventional approaches that utilize LC-electrochemical detection (ECD) (LOQ 150â¯nM or higher). The method was assessed in a pharmacokinetics study in rats administered Amifostine intravenously and via direct jejunal injection (10â¯mg/kg each route). The bioavailability of WR-1065 was 61.5% after direct jejunal injection indicating rapid conversion and absorption of the metabolite in the intestinal tract. This demonstrates that an oral formulation of Amifostine designed for site-specific release of the drug in the upper GI tract can deliver systemic absorption/conversion to WR-1065, provided that the formulation protects the therapeutic from gastric decomposition in the stomach.