RESUMEN
Babesia and Plasmodium pathogens, the causative agents of babesiosis and malaria, are vector-borne intraerythrocytic protozoan parasites, posing significant threats to both human and animal health. The widespread resistance exhibited by these pathogens to various classes of antiparasitic drugs underscores the need for the development of novel and more effective therapeutic strategies. Antifolates have long been recognized as attractive antiparasitic drugs as they target the folate pathway, which is essential for the biosynthesis of purines and pyrimidines, and thus is vital for the survival and proliferation of protozoan parasites. More efficacious and safer analogs within this class are needed to overcome challenges due to resistance to commonly used antifolates, such as pyrimethamine, and to address liabilities associated with the dihydrotriazines, WR99210 and JPC-2067. Here, we utilized an in vitro culture condition suitable for the continuous propagation of Babesia duncani, Babesia divergens, Babesia MO1, and Plasmodium falciparum in human erythrocytes to screen a library of 50 dihydrotriazines and 29 biguanides for their efficacy in vitro and compared their potency and therapeutic indices across different species and isolates. We identified nine analogs that inhibit the growth of all species, including the P. falciparum pyrimethamine-resistant strain HB3, with IC50 values below 10 nM, and display excellent in vitro therapeutic indices. These compounds hold substantial promise as lead antifolates for further development as broad-spectrum antiparasitic drugs.
RESUMEN
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between 3TUG times and lower extremity function scores was significant in subjects who continued and in those who were withdrawn from 3,4-diaminopyridine free base.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.
Asunto(s)
Síndrome Miasténico de Lambert-Eaton/fisiopatología , Extremidad Inferior/fisiopatología , Debilidad Muscular/fisiopatología , Humanos , Tamizaje Masivo/métodos , Debilidad Muscular/tratamiento farmacológico , Bloqueadores de los Canales de Potasio/uso terapéutico , Reproducibilidad de los Resultados , Índice de Severidad de la EnfermedadRESUMEN
The new 2-aminomethylphenol, JPC-3210, has potent in vitro antimalarial activity against multidrug-resistant Plasmodium falciparum lines, low cytotoxicity, and high in vivo efficacy against murine malaria. Here we report on the pharmacokinetics of JPC-3210 in mice and monkeys and the results of in vitro screening assays, including the inhibition of cytochrome P450 (CYP450) isozymes. In mice, JPC-3210 was rapidly absorbed and had an extensive tissue distribution, with a brain tissue-to-plasma concentration ratio of about 5.4. JPC-3210 had a lengthy plasma elimination half-life of about 4.5 days in mice and 11.8 days in monkeys. JPC-3210 exhibited linear single-oral-dose pharmacokinetics across the dose range of 5 to 40 mg/kg of body weight with high oral bioavailability (â¼86%) in mice. Systemic blood exposure of JPC-3210 was 16.6% higher in P. berghei-infected mice than in healthy mice. In vitro studies with mice and human hepatocytes revealed little metabolism and the high metabolic stability of JPC-3210. The abundance of human metabolites from oxidation and glucuronidation was 2.0% and 2.5%, respectively. CYP450 studies in human liver microsomes showed JPC-3210 to be an inhibitor of CYP2D6 and, to a lesser extent, CYP3A4 isozymes, suggesting the possibility of a metabolic drug-drug interaction with drugs that are metabolized by these isozymes. In vitro studies showed that JPC-3210 is highly protein bound to human plasma (97%). These desirable pharmacological findings of a lengthy blood elimination half-life, high oral bioavailability, and low metabolism as well as high in vivo potency have led the Medicines for Malaria Venture to select JPC-3210 (MMV892646) for further advanced preclinical development.
Asunto(s)
Antimaláricos/uso terapéutico , Malaria/tratamiento farmacológico , Malaria/prevención & control , Animales , Antimaláricos/química , Células Cultivadas , Sistema Enzimático del Citocromo P-450/metabolismo , Resistencia a Múltiples Medicamentos , Femenino , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Humanos , Masculino , Ratones , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Unión Proteica , RatasRESUMEN
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.
Asunto(s)
Amifampridina/uso terapéutico , Deprescripciones , Síndrome Miasténico de Lambert-Eaton/tratamiento farmacológico , Debilidad Muscular/tratamiento farmacológico , Fármacos Neuromusculares/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Método Doble Ciego , Femenino , Humanos , Síndrome Miasténico de Lambert-Eaton/complicaciones , Quimioterapia de Mantención , Masculino , Persona de Mediana Edad , Debilidad Muscular/etiología , Adulto JovenRESUMEN
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.
Asunto(s)
Antimaláricos/uso terapéutico , Malaria Falciparum/tratamiento farmacológico , Malaria/tratamiento farmacológico , Fenoles/uso terapéutico , Animales , Línea Celular , Cricetinae , Células HEK293 , Células Hep G2 , Humanos , Mefloquina/uso terapéutico , Ratones , Plasmodium falciparum/efectos de los fármacos , Plasmodium falciparum/patogenicidad , Piridinas/uso terapéuticoRESUMEN
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.