RESUMO
Bedaquiline (BDQ) is an antibiotic to treat pulmonary multidrug-resistant tuberculosis (MDR-TB). Studies up to 39 weeks were conducted orally in dogs to assess the toxicity and pharmacokinetics of BDQ and its N-desmethyl metabolite (D-BDQ). Phospholipidosis (PLD) seen in the monocytic phagocytic system was considered an adaptive change. Skeletal muscle, heart, stomach, liver, and pancreas toxicities with D-BDQ as the main contributor were associated with a less-than-dose-proportional increase in plasma exposure and an overproportional tissue uptake of BDQ and D-BDQ at high-dose levels. Tissue concentrations of BDQ and D-BDQ slowly decreased after lowering the dose, contributing to the recovery of the pathological findings. Treatment was better tolerated at mid-dose levels, characterized by a dose-proportional increase in plasma and tissue exposures. Treatment at a low dose, reaching exposures approximating therapeutic exposures, was without adverse effects and not associated with PLD. There was no evidence of delayed toxicities after treatment cessation. Intermittent dosing was better tolerated at high doses. Since MDR-TB patients are dosed within the linear plasma exposure range and plasma levels of BDQ and D-BDQ are similar or lower than in dogs, PLD and adverse findings related to tissue accumulation that occurred at high doses in dogs are unlikely to occur in humans.
Assuntos
Antituberculosos/farmacocinética , Antituberculosos/toxicidade , Diarilquinolinas/farmacocinética , Diarilquinolinas/toxicidade , Administração Oral , Animais , Antituberculosos/administração & dosagem , Antituberculosos/química , Diarilquinolinas/administração & dosagem , Diarilquinolinas/química , Cães , Feminino , Masculino , Músculo Esquelético/química , Músculo Esquelético/metabolismo , Miocárdio/química , Miocárdio/metabolismo , Pâncreas/química , Pâncreas/metabolismo , Fosfolipídeos/análise , Fosfolipídeos/química , Distribuição TecidualRESUMO
JNJ-37822681 is a potent, specific and fast dissociating dopamine D2 receptor antagonist intended for the treatment of schizophrenia. Its nonclinical toxicological profile was investigated in a series of general repeat dose toxicity studies in cynomolgus monkeys and Sprague-Dawley rats. The maximum duration of treatment was 9 and 6 months, respectively. Interspecies differences were noted in the response to JNJ-37822681 in terms of extrapyramidal (EPS)-like clinical signs and prolactin-mediated tissue changes in the mammary gland. Monkeys showed severe EPS-like clinical signs such as abnormal posture, abnormal eye movements and hallucination-like behavior at relatively low exposures compared to those associated with EPS in patients with schizophrenia. The high sensitivity of the monkey to JNJ-37822681-induced EPS-like signs was unexpected based on the fast dissociating properties of the compound. Rats, however, were not prone to EPS. Elevated serum prolactin levels were found in rats and monkeys. While rats showed slight to moderate prolactin-related tissue changes upon histopathological examination in all studies, which among others affected the mammary gland, only minor mammary gland tissue changes were noted in monkeys. Prolactin levels were only slightly increased in patients with schizophrenia receiving relatively high dose levels of JNJ-37822681. The monkey toxicology studies did not provide an exposure-based safety margin, while in rats adverse effects were only noted at exposures considerably higher than those achieved at efficacious plasma concentrations in the clinic. Overall, the available data suggest that the cynomolgus monkey showed better predictivity towards the nature of JNJ-37822681-associated adverse events in humans than the Sprague-Dawley rat.
Assuntos
Antagonistas dos Receptores de Dopamina D2/toxicidade , Glândulas Mamárias Animais/patologia , Piperidinas/farmacocinética , Piperidinas/toxicidade , Prolactina/metabolismo , Piridazinas/farmacocinética , Piridazinas/toxicidade , Animais , Antipsicóticos/farmacocinética , Antipsicóticos/uso terapêutico , Antipsicóticos/toxicidade , Relação Dose-Resposta a Droga , Feminino , Humanos , Macaca fascicularis , Masculino , Piperidinas/uso terapêutico , Piridazinas/uso terapêutico , Ratos , Ratos Sprague-Dawley , Esquizofrenia/tratamento farmacológico , Testes de ToxicidadeRESUMO
The detection of drug-induced hepatotoxicity remains an important safety issue in drug development. A liver-specific microRNA species, microRNA-122 (miR-122), has recently shown potential for predicting liver injury in addition to the standard hepatic injury biomarkers. The objective of this study was to measure miR-122 together with several other liver markers in distinct settings of acute liver toxicity in rats to determine the value of miR-122 as a biomarker for liver injury in this species. Rats were exposed to 3 well-established liver toxicants (acetaminophen, allyl alcohol, and α-naphthyl isothiocyanate), a liver-enzyme inducer (phenobarbital), or a cardiotoxicant (doxorubicin). There was a clear increase in plasma miR-122 following administration of acetaminophen, allyl alcohol, and α-naphthyl isothiocyanate. The response of miR-122 paralleled that of other markers and was consistent with liver injury as indicated by histopathological evaluation. Furthermore, the changes in miR-122 were detected earlier than standard liver injury markers and exhibited a wide dynamic range. In contrast, miR-122 responses to phenobarbital and doxorubicin were low. Based on these findings, miR-122 shows significant promise and may provide added value for assessing liver toxicity in drug development.
Assuntos
Doença Hepática Induzida por Substâncias e Drogas/sangue , MicroRNAs/sangue , Acetaminofen/toxicidade , Animais , Biomarcadores/sangue , Doença Hepática Induzida por Substâncias e Drogas/genética , Doença Hepática Induzida por Substâncias e Drogas/patologia , Isocianatos/toxicidade , Fígado/química , Fígado/patologia , Masculino , Naftalenos/toxicidade , Propanóis/toxicidade , Ratos , Ratos Sprague-Dawley , Testes de Toxicidade AgudaRESUMO
The kidney is one of the main targets of drug toxicity, and early detection of renal damage is critical in preclinical drug development. A model of cisplatin-induced nephrotoxicity in male Sprague Dawley rats treated for 1, 3, 5, 7, or 14 days at 1 mg/kg/day was used to monitor the spatial and temporal expression of various indicators of kidney toxicity during the progression of acute kidney injury (AKI). As early as 1 day after cisplatin treatment, positive kidney injury molecule-1 (Kim-1) immunostaining, observed in the outer medulla of the kidney, and changes in urinary clusterin indicated the onset of proximal tubular injury in the absence of functional effects. After 3 days of treatment, Kim-1 protein levels in urine increased more than 20-fold concomitant with a positive clusterin immunostaining and an increase in urinary osteopontin. Tubular basophilia was also noted, while serum creatinine and blood urea nitrogen levels were elevated only after 5 days, together with tubular degeneration. In conclusion, tissue Kim-1 and urinary clusterin were the most sensitive biomarkers for detection of cisplatin-induced kidney damage. Thereafter, urinary Kim-1 and osteopontin, as well as clusterin immunostaining accurately correlated with the histopathological findings. When AKI is suspected in preclinical rat studies, Kim-1, clusterin, and osteopontin should be part of urinalysis and/or IHC can be performed.
Assuntos
Antineoplásicos/toxicidade , Cisplatino/toxicidade , Clusterina/urina , Nefropatias/induzido quimicamente , Proteínas de Membrana/metabolismo , Testes de Toxicidade/métodos , Animais , Biomarcadores/metabolismo , Análise Química do Sangue , Peso Corporal/efeitos dos fármacos , Modelos Animais de Doenças , Receptor Celular 1 do Vírus da Hepatite A , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Nefropatias/metabolismo , Nefropatias/patologia , Túbulos Renais/efeitos dos fármacos , Túbulos Renais/metabolismo , Túbulos Renais/patologia , Masculino , Tamanho do Órgão/efeitos dos fármacos , Osteopontina/urina , Ratos , Ratos Sprague-Dawley , UrináliseRESUMO
To provide mechanistic insight in the induction of phospholipidosis and the appearance of the proposed biomarker di-docosahexaenoyl (C22:6)-bis(monoacylglycerol) phosphate (BMP), rats were treated with 150 mg/kg amiodarone for 12 consecutive days and analyzed at three different time points (day 4, 9, and 12). Biochemical analysis of the serum revealed a significant increase in cholesterol and phospholipids at the three time points. Bio-analysis on the serum and urine detected a time-dependent increase in BMP, as high as 10-fold compared to vehicle-treated animals on day 12. Paralleling these increases, micro-array analysis on the liver of treated rats identified cholesterol biosynthesis and glycerophospholipid metabolism as highly modulated pathways. This modulation indicates that during phospholipidosis-induction interactions take place between the cationic amphiphilic drug and phospholipids at the level of BMP-rich internal membranes of endosomes, impeding cholesterol sorting and leading to an accumulation of internal membranes, converting into multilamellar bodies. This process shows analogy to Niemann-Pick disease type C (NPC). Whereas the NPC-induced lipid traffic jam is situated at the cholesterol sorting proteins NPC1 and NPC2, the amiodarone-induced traffic jam is thought to be located at the BMP level, demonstrating its role in the mechanism of phospholipidosis-induction and its significance for use as a biomarker.
Assuntos
Amiodarona/toxicidade , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipidoses/induzido quimicamente , Lisofosfolipídeos/sangue , Lisofosfolipídeos/urina , Animais , Biomarcadores/sangue , Biomarcadores/urina , Colesterol/sangue , Regulação da Expressão Gênica , Glicerofosfolipídeos/sangue , Glicerofosfolipídeos/metabolismo , Lipidoses/sangue , Lipidoses/urina , Fígado/patologia , Pulmão/patologia , Linfócitos/efeitos dos fármacos , Linfócitos/patologia , Masculino , Redes e Vias Metabólicas/efeitos dos fármacos , Análise de Sequência com Séries de Oligonucleotídeos , Tamanho do Órgão/efeitos dos fármacos , Fosfolipídeos/sangue , Ratos , Ratos Sprague-Dawley , Baço/patologia , ToxicogenéticaRESUMO
BACKGROUND: Flubendazole, originally developed to treat infections with intestinal nematodes, has been shown to be efficacious in animal models of filarial infections. For treatment of filarial nematodes, systemic exposure is needed. For this purpose, an orally bioavailable amorphous solid dispersion (ASD) formulation of flubendazole was developed. As this formulation results in improved systemic absorption, the pharmacokinetic and toxicological profile of the flubendazole ASD formulation have been assessed to ensure human safety before clinical trials could be initiated. METHODS & FINDINGS: Safety pharmacology, toxicity and genotoxicity studies have been conducted with the flubendazole ASD formulation. In animals, flubendazole has good oral bioavailability from an ASD formulation ranging from 15% in dogs, 27% in rats to more than 100% in jirds. In in vivo toxicity studies with the ASD formulation, high systemic exposure to flubendazole and its main metabolites was reached. Flubendazole, up to high peak plasma concentrations, does not induce Cmax related effects in CNS or cardiovascular system. In repeated dose toxicity studies in rats and dogs, flubendazole-induced changes were observed in haematological, lymphoid and gastrointestinal systems and in testes. In dogs, the liver was an additional target organ. Upon treatment cessation, at least partial recovery was observed for these changes in dogs. In rats, the No Observed Adverse Effect Level (NOAEL) was 5 mg (as base)/kg body weight/day (mg eq./kg/day) in males and 2.5 mg eq./kg/day in females. In dogs, the NOAEL was lower than 20 mg eq./kg/day. Regarding genotoxicity, flubendazole was negative in the Ames test, but positive in the in vivo micronucleus test. CONCLUSIONS: Based on these results, in combination with previously described genotoxicity and reproductive toxicity data and the outcome of the preclinical efficacy studies, it was concluded that no flubendazole treatment regimen can be selected that would provide efficacy in humans at safe exposure.
Assuntos
Antinematódeos/efeitos adversos , Antinematódeos/farmacocinética , Mebendazol/análogos & derivados , Testes de Mutagenicidade , Administração Oral , Animais , Antinematódeos/administração & dosagem , Cães , Avaliação Pré-Clínica de Medicamentos , Feminino , Gerbillinae , Masculino , Mebendazol/administração & dosagem , Mebendazol/efeitos adversos , Mebendazol/farmacocinética , Ratos Sprague-DawleyRESUMO
In order to support drug research in the selection process for non-embryotoxic pharmaceutical compounds, a screening method for embryotoxicity is needed. The murine embryonic stem cell test (EST) is a validated in vitro test based on two permanent mouse cell lines and delivering results in 10-days. Implementation of this test within our laboratory, revealed variability in the differentiation potential of the embryonic stem cells and, as a consequence, a lot of assays needed to be rejected due the fact the acceptance criteria were not reached. In order to gain a better yield of contracting myocardial cells, we used (1) a stringent control of the cell growth during subcultivation and a standardised hanging drop culture method and (2) a non-enzymatic cell harvest instead of a trypsin/EDTA cell harvest. Implementing of these cell culture modifications resulted in a decreased variability in the size of embryonic bodies, an increase of the number of acceptable tests and a significant increase of the differentiation potential of embryonic cells into strong beating myocardium, which made scoring less time consuming. Testing of 6 reference compounds in the optimized EST showed that the cell culture modifications did not changed the in vitro classification.
Assuntos
Técnicas de Cultura de Células/métodos , Diferenciação Celular/efeitos dos fármacos , Células-Tronco Embrionárias/efeitos dos fármacos , Testes de Toxicidade/métodos , Animais , Células 3T3 BALB , Ácido Edético/metabolismo , Células-Tronco Embrionárias/metabolismo , Camundongos , Miocárdio/citologia , Tripsina/metabolismoRESUMO
Ideally, an anti-HIV drug should (1) be highly active against wild-type and mutant HIV without allowing breakthrough; (2) have high oral bioavailability and long elimination half-life, allowing once-daily oral treatment at low doses; (3) have minimal adverse effects; and (4) be easy to synthesize and formulate. R278474, a new diarylpyrimidine (DAPY) non-nucleoside reverse transcriptase inhibitor (NNRTI), appears to meet these criteria and to be suitable for high compliance oral treatment of HIV-1 infection. The discovery of R278474 was the result of a coordinated multidisciplinary effort involving medicinal chemists, virologists, crystallographers, molecular modelers, toxicologists, analytical chemists, pharmacists, and many others.
Assuntos
Fármacos Anti-HIV , Nitrilas , Pirimidinas , Administração Oral , Fármacos Anti-HIV/síntese química , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Disponibilidade Biológica , Cristalografia por Raios X , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Genoma Viral , HIV/genética , HIV/isolamento & purificação , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , Humanos , Comunicação Interdisciplinar , Modelos Moleculares , Estrutura Molecular , Mutação , Nitrilas/síntese química , Nitrilas/química , Nitrilas/farmacologia , Pirimidinas/síntese química , Pirimidinas/química , Pirimidinas/farmacologia , RilpivirinaRESUMO
According to the current Organization of Economic Cooperation and Development (OECD) and International Committee on Harmonization (ICH) guidelines for the mammalian erythrocyte micronucleus (MN) test, analysis of peripheral blood reticulocytes (RETs) for the presence of micronuclei can be performed using flow cytometry. The MicroFlow PLUS method (Litron Laboratories, Rochester, NY) for MN analysis by flow cytometry is based on the binding of FITC-labeled antibodies to the CD71 transferrin receptor of immature RETs, on parallel RNA degradation, and on propidium iodide staining of DNA present as micronuclei. The objective of this study was to assess the sensitivity of this flow cytometry method to detect time- and dose-dependent induction of micronuclei in mouse peripheral blood RETs after treatment with nine chemical agents. Five known clastogens, two known aneugens, and two compounds previously reported to be inactive in the mouse bone marrow MN test were evaluated at three dose levels. Multiple blood sampling of the same animal before and at two time points after treatment was conducted. All known mutagens produced a dose-dependent increase in micronucleated reticulocytes (MN-RETs); the compounds previously shown to be inactive in the in vivo MN test were also negative using the present methodology. The highest frequency of MN-RETs was observed at 48 hr after treatment, except for 5-fluorouracil, which had its peak response at 72 hr. The results indicate that micronuclei can be measured by multiple blood sampling of the same animal before and after treatment without altering the sensitivity of the assay. The results confirm that the flow cytometric assessment of MN-RETs in mouse peripheral blood using MicroFlow PLUS is a sensitive method with high analysis throughput, and robust quality control.
Assuntos
Coleta de Amostras Sanguíneas/métodos , Citometria de Fluxo , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Mutagênicos/toxicidade , Reticulócitos/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Masculino , Camundongos , Testes para Micronúcleos/métodos , Reticulócitos/metabolismo , Fatores de TempoRESUMO
PURPOSE: The receptor tyrosine kinase c-Met plays an important role in tumorigenesis and is a novel target for anticancer treatment. This phase I, first-in-human trial, explored safety, pharmacokinetics, pharmacodynamics, and initial antitumor activity of JNJ-38877605, a potent and selective c-Met inhibitor. EXPERIMENTAL DESIGN: We performed a phase I dose-escalation study according to the standard 3+3 design. RESULTS: Even at subtherapeutic doses, mild though recurrent renal toxicity was observed in virtually all patients. Renal toxicity had not been observed in preclinical studies in rats and dogs. Additional preclinical studies pointed toward the rabbit as a suitable toxicology model, as the formation of the M10 metabolite of JNJ-38877605 specifically occurred in rabbits and humans. Additional toxicology studies in rabbits clearly demonstrated that JNJ-38877605 induced species-specific renal toxicity. Histopathological evaluation in rabbits revealed renal crystal formation with degenerative and inflammatory changes. Identification of the components of these renal crystals revealed M1/3 and M5/6 metabolites. Accordingly, it was found that humans and rabbits showed significantly increased systemic exposure to these metabolites relative to other species. These main culprit insoluble metabolites were generated by aldehyde oxidase activity. Alternative dosing schedules of JNJ-3877605 and concomitant probenecid administration in rabbits failed to prevent renal toxicity at dose levels that could be pharmacologically active. CONCLUSIONS: Combined clinical and correlative preclinical studies suggest that renal toxicity of JNJ-38877605 is caused by the formation of species-specific insoluble metabolites. These observations preclude further clinical development of JNJ-38877605.
Assuntos
Antineoplásicos/administração & dosagem , Neoplasias Colorretais/tratamento farmacológico , Rim/patologia , Pirazóis/administração & dosagem , Piridazinas/administração & dosagem , Adulto , Idoso , Animais , Antineoplásicos/farmacocinética , Antineoplásicos/toxicidade , Cães , Feminino , Humanos , Inativação Metabólica , Rim/efeitos dos fármacos , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Pirazóis/farmacocinética , Pirazóis/toxicidade , Piridazinas/farmacocinética , Piridazinas/toxicidade , Coelhos , Ratos , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Especificidade da EspécieRESUMO
Regulatory guidelines indicate acute toxicity studies in animals are considered necessary for pharmaceuticals intended for human use. This is the only study type where lethality is mentioned as an endpoint. The studies are carried out, usually in rodents, to support marketing of new drugs and to identify the minimum lethal dose. A European initiative including 18 companies has undertaken an evidence-based review of acute toxicity studies and assessed the value of the data generated. Preclinical and clinical information was shared on 74 compounds. The analysis indicated acute toxicity data was not used to (i) terminate drugs from development (ii) support dose selection for repeat dose studies in animals or (iii) to set doses in the first clinical trials in humans. The conclusion of the working group is that acute toxicity studies are not needed prior to first clinical trials in humans. Instead, information can be obtained from other studies, which are performed at more relevant doses for humans and are already an integral part of drug development. The conclusions have been discussed and agreed with representatives of regulatory bodies from the US, Japan and Europe.