RESUMO
The increasing incidence of antimalarial drug resistance to the first-line artemisinin combination therapies underpins an urgent need for new antimalarial drugs, ideally with a novel mode of action. The recently developed 2-aminomethylphenol, JPC-3210, (MMV 892646) is an erythrocytic schizonticide with potent in vitro antimalarial activity against multidrug-resistant Plasmodium falciparum lines, low cytotoxicity, potent in vivo efficacy against murine malaria, and favorable preclinical pharmacokinetics including a lengthy plasma elimination half-life. To investigate the impact of JPC-3210 on biochemical pathways within P. falciparum-infected red blood cells, we have applied a "multi-omics" workflow based on high resolution orbitrap mass spectrometry combined with biochemical approaches. Metabolomics, peptidomics and hemoglobin fractionation analyses revealed a perturbation in hemoglobin metabolism following JPC-3210 exposure. The metabolomics data demonstrated a specific depletion of short hemoglobin-derived peptides, peptidomics analysis revealed a depletion of longer hemoglobin-derived peptides, and the hemoglobin fractionation assay demonstrated decreases in hemoglobin, heme and hemozoin levels. To further elucidate the mechanism responsible for inhibition of hemoglobin metabolism, we used in vitro ß-hematin polymerization assays and showed JPC-3210 to be an intermediate inhibitor of ß-hematin polymerization, about 10-fold less potent then the quinoline antimalarials, such as chloroquine and mefloquine. Further, quantitative proteomics analysis showed that JPC-3210 treatment results in a distinct proteomic signature compared with other known antimalarials. While JPC-3210 clustered closely with mefloquine in the metabolomics and proteomics analyses, a key differentiating signature for JPC-3210 was the significant enrichment of parasite proteins involved in regulation of translation. These studies revealed that the mode of action for JPC-3210 involves inhibition of the hemoglobin digestion pathway and elevation of regulators of protein translation. Importantly, JPC-3210 demonstrated rapid parasite killing kinetics compared with other quinolones, suggesting that JPC-3210 warrants further investigation as a potentially long acting partner drug for malaria treatment.
Assuntos
Antimaláricos/farmacologia , Fenóis/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Hemoglobinas/metabolismo , Metabolômica , Peptídeos/metabolismo , Plasmodium falciparum/metabolismo , Proteômica , Proteínas de Protozoários/metabolismoRESUMO
INTRODUCTION: There are no validated, practical, and quantitative measures of disease severity in Lambert-Eaton myasthenia (LEM). METHODS: Data from the Effectiveness of 3,4-Diaminopyridine in Lambert-Eaton Myasthenic Syndrome (DAPPER) trial were analyzed to assess triple timed up-and-go (3TUG) reproducibility and relationships between 3TUG times and other measures of LEM severity. RESULTS: The coverage probability technique showed ≥0.90 probability for an acceptable 3TUG difference of ≤0.2, indicating that it is reproducible in LEM patients. The correlation between 3TUG times and lower extremity function scores was significant in subjects who continued and in those who were withdrawn from 3,4-diaminopyridine free base. Worsening patient-reported Weakness Self-Assessment Scale and Investigator Assessment of Treatment Effect scores corresponded with prolongation of 3TUG times. DISCUSSION: The 3TUG is reproducible, demonstrates construct validity for assessment of lower extremity function in LEM patients, and correlates with changes in patient and physician assessments. These findings, along with prior reliability studies, indicate 3TUG is a valid measure of disease severity in LEM.
Assuntos
Síndrome Miastênica de Lambert-Eaton/fisiopatologia , Extremidade Inferior/fisiopatologia , Debilidade Muscular/fisiopatologia , Humanos , Programas de Rastreamento/métodos , Debilidade Muscular/tratamento farmacológico , Bloqueadores dos Canais de Potássio/uso terapêutico , Reprodutibilidade dos Testes , Índice de Gravidade de DoençaRESUMO
INTRODUCTION: 3,4-diaminopyridine has been used to treat Lambert-Eaton myasthenia (LEM) for 30 years despite the lack of conclusive evidence of efficacy. METHODS: We conducted a randomized double-blind placebo-controlled withdrawal study in patients with LEM who had been on stable regimens of 3,4-diaminopyridine base (3,4-DAP) for ≥ 3 months. The primary efficacy endpoint was >30% deterioration in triple timed up-and-go (3TUG) times during tapered drug withdrawal. The secondary endpoint was self-assessment of LEM-related weakness (W-SAS). RESULTS: Thirty-two participants were randomized to continuous 3,4-DAP or placebo groups. None of the 14 participants who received continuous 3,4-DAP had > 30% deterioration in 3TUG time versus 72% of the 18 who tapered to placebo (P < 0.0001). W-SAS similarly demonstrated an advantage for continuous treatment over placebo (P < 0.0001). Requirement for rescue and adverse events were more common in the placebo group. DISCUSSION: This trial provides significant evidence of efficacy of 3,4-DAP in the maintenance of strength in LEM. Muscle Nerve 57: 561-568, 2018.
Assuntos
Amifampridina/uso terapêutico , Desprescrições , Síndrome Miastênica de Lambert-Eaton/tratamento farmacológico , Debilidade Muscular/tratamento farmacológico , Fármacos Neuromusculares/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Método Duplo-Cego , Feminino , Humanos , Síndrome Miastênica de Lambert-Eaton/complicações , Quimioterapia de Manutenção , Masculino , Pessoa de Meia-Idade , Debilidade Muscular/etiologia , Adulto JovemRESUMO
INTRODUCTION: We report the reliability of a new measure, the triple-timed up-and-go (3TUG) test, for assessing clinical function in patients with Lambert-Eaton myasthenia (LEM). METHODS: Intrarater reproducibility and interrater agreement of the 3TUG test were assessed in 25 control participants, 24 patients with non-LEM neuromuscular disease, and 12 patients with LEM. The coverage probability (CP) method was the primary measure of reproducibility and agreement. The a priori acceptable range was < 20% difference in 3TUG test times and a CP ≥0.90 confirmed agreement. RESULTS: CP values > 0.90 for intrarater and interrater tests confirmed acceptable reproducibility and agreement for all groups. DISCUSSION: The 3TUG test is a quick, noninvasive, and reproducible measure that is easy to perform, measures clinically important weakness in LEM patients, and requires little training. Additional evaluation in a larger number of LEM patients is in progress to validate the 3TUG test as a clinical measure in LEM. Muscle Nerve 57: 136-139, 2017.
Assuntos
Síndrome Miastênica de Lambert-Eaton/diagnóstico , Adulto , Avaliação da Deficiência , Determinação de Ponto Final , Feminino , Humanos , Síndrome Miastênica de Lambert-Eaton/fisiopatologia , Masculino , Pessoa de Meia-Idade , Exame Neurológico , Doenças Neuromusculares/diagnóstico , Doenças Neuromusculares/fisiopatologia , Variações Dependentes do Observador , Reprodutibilidade dos TestesRESUMO
Structure-activity relationship studies of trifluoromethyl-substituted pyridine and pyrimidine analogues of 2-aminomethylphenols (JPC-2997, JPC-3186, and JPC-3210) were conducted for preclinical development for malaria treatment and/or prevention. Of these compounds, JPC-3210 [4-(tert-butyl)-2-((tert-butylamino)methyl)-6-(5-fluoro-6-(trifluoromethyl)pyridin-3-yl)phenol] was selected as the lead compound due to superior in vitro antimalarial activity against multidrug-resistant Plasmodium falciparum lines, lower in vitro cytotoxicity in mammalian cell lines, longer plasma elimination half-life, and greater in vivo efficacy against murine malaria.
Assuntos
Antimaláricos/uso terapêutico , Malária Falciparum/tratamento farmacológico , Malária/tratamento farmacológico , Fenóis/uso terapêutico , Animais , Linhagem Celular , Cricetinae , Células HEK293 , Células Hep G2 , Humanos , Mefloquina/uso terapêutico , Camundongos , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/patogenicidade , Piridinas/uso terapêuticoRESUMO
4-(tert-Butyl)-2-((tert-butylamino)methyl)-6-(6-(trifluoromethyl)pyridin-3-yl)-phenol (JPC-2997) is a new aminomethylphenol compound that is highly active in vitro against the chloroquine-sensitive D6, the chloroquine-resistant W2, and the multidrug-resistant TM90-C2B Plasmodium falciparum lines, with 50% inhibitory concentrations (IC50s) ranging from 7 nM to 34 nM. JPC-2997 is >2,500 times less cytotoxic (IC50s > 35 µM) to human (HepG2 and HEK293) and rodent (BHK) cell lines than the D6 parasite line. In comparison to the chemically related WR-194,965, a drug that had advanced to clinical studies, JPC-2997 was 2-fold more active in vitro against P. falciparum lines and 3-fold less cytotoxic. The compound possesses potent in vivo suppression activity against Plasmodium berghei, with a 50% effective dose (ED50) of 0.5 mg/kg of body weight/day following oral dosing in the Peters 4-day test. The radical curative dose of JPC-2997 was remarkably low, at a total dose of 24 mg/kg, using the modified Thompson test. JPC-2997 was effective in curing three Aotus monkeys infected with a chloroquine- and pyrimethamine-resistant strain of Plasmodium vivax at a dose of 20 mg/kg daily for 3 days. At the doses administered, JPC-2997 appeared to be well tolerated in mice and monkeys. Preliminary studies of JPC-2997 in mice show linear pharmacokinetics over the range 2.5 to 40 mg/kg, a low clearance of 0.22 liters/h/kg, a volume of distribution of 15.6 liters/kg, and an elimination half-life of 49.8 h. The high in vivo potency data and lengthy elimination half-life of JPC-2997 suggest that it is worthy of further preclinical assessment as a partner drug.
Assuntos
Antimaláricos/uso terapêutico , Malária Falciparum/tratamento farmacológico , Fenóis/uso terapêutico , Plasmodium falciparum/efeitos dos fármacos , Piridinas/uso terapêutico , Animais , Antimaláricos/efeitos adversos , Antimaláricos/farmacocinética , Aotidae , Linhagem Celular , Cricetinae , Resistência a Medicamentos , Células HEK293 , Células Hep G2 , Humanos , Camundongos , Testes de Sensibilidade Parasitária , Fenóis/efeitos adversos , Fenóis/farmacocinética , Plasmodium berghei/efeitos dos fármacos , Plasmodium vivax/efeitos dos fármacos , Piridinas/efeitos adversos , Piridinas/farmacocinéticaRESUMO
2'-Substituted analogs of triclosan have been synthesized to target inhibition of the key malarial enzyme Plasmodium falciparum enoyl acyl carrier protein reductase (PfENR). Many of these compounds exhibit good potency (EC50<500 nM) against in vitro cultures of drug-resistant and drug-sensitive strains of the P. falciparum parasite and modest (IC50=1-20 microM) potency against purified PfENR enzyme. Compared to triclosan, this survey of 2'-substituted derivatives has afforded gains in excess of 20- and 30-fold versus the 3D7 and Dd2 strains of parasite, respectively.
Assuntos
Antimaláricos/síntese química , Antimaláricos/farmacologia , Enoil-(Proteína de Transporte de Acila) Redutase (NADH)/antagonistas & inibidores , Éteres/antagonistas & inibidores , Plasmodium falciparum/efeitos dos fármacos , Triclosan/química , Animais , Cristalografia por Raios X , Resistência Microbiana a Medicamentos , Relação Estrutura-Atividade , Triclosan/análogos & derivadosRESUMO
A structure-based approach has been taken to develop 4'-substituted analogs of triclosan that target the key malarial enzyme Plasmodium falciparum enoyl acyl carrier protein reductase (PfENR). Many of these compounds exhibit nanomolar potency against purified PfENR enzyme and modest (2-10microM) potency against in vitro cultures of drug-resistant and drug-sensitive strains of the P. falciparum parasite. X-ray crystal structures of nitro 29, aniline 30, methylamide 37, and urea 46 demonstrate the presence of hydrogen-bonding interactions with residues in the active site and point to future rounds of optimization to improve compound potency against purified enzyme and intracellular parasites.