Randomized, double-blind, placebo-controlled, phase I study of the safety and pharmacokinetics of namilumab in healthy Japanese and Caucasian men
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OBJECTIVE: Namilumab is an investigational human monoclonal antibody to human granulocyte-macrophage colony-stimulating factor (GM-CSF). A phase I study of repeated namilumab dosing (150 or 300 mg subcutaneously) in non-Japanese patients with rheumatoid arthritis reported no safety concerns. The objective of this study was to report the safety (primary endpoint) and pharmacokinetic/pharmacodynamic effects of namilumab in healthy Japanese and Caucasian men aged 20 - 45 years (NCT02354599). MATERIALS AND METHODS: 24 Japanese subjects were randomized to a single dose of namilumab (80, 150, or 300 mg; n = 6/group) or placebo (n = 6; 2 subjects randomized/matched dose); 8 Caucasian subjects received namilumab 150 mg (n = 6) or placebo (n = 2). RESULTS: Overall, 29 subjects completed the study (2 withdrew voluntarily; 1 due to a serious adverse event (AE) unrelated to treatment). Baseline demographics were similar across treatment groups; mean age and weight were higher in Caucasians. Namilumab was well tolerated, with no notable safety concerns or pharmacokinetic/pharmacodynamic differences between Japanese and Caucasian subjects. AEs were mild to moderate, with no dose-proportional increase in Japanese subjects. Area under the serum concentration-time curve from zero to infinity (AUC0-∞) and maximum serum concentration (Cmax) increased in a dose-proportional manner in Japanese subjects. AUC0-∞ was similar in Japanese (575.2 µg×day/mL) and Caucasian (559.7 µg×day/mL) 150-mg groups. Cmax was ~ 40% higher in Japanese subjects. Mean plasma total GM-CSF concentration-time profiles were similar in the Japanese and Caucasian 150-mg groups. Namilumab induced no clinically-relevant antibody response. CONCLUSION: Namilumab was well tolerated in Japanese and Caucasian subjects; namilumab 150 mg had similar pharmacokinetics in both populations, supporting further clinical development of this dose.
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Effect of heliquinomycin on the activity of human minichromosome maintenance 4/6/7 helicase.

The antibiotic heliquinomycin, which inhibits cellular DNA replication at a half-maximal inhibitory concentration (IC(50)) of 1.4-4 microM, was found to inhibit the DNA helicase activity of the human minichromosome maintenance (MCM) 4/6/7 complex at an IC(50) value of 2.4 microM. In contrast, 14 microM heliquinomycin did not inhibit significantly either the DNA helicase activity of the SV40 T antigen and Werner protein or the oligonucleotide displacement activity of human replication protein A. At IC(50) values of 25 and 6.5 microM, heliquinomycin inhibited the RNA priming and DNA polymerization activities, respectively, of human DNA polymerase-alpha/primase. Thus, of the enzymes studied, the MCM4/6/7 complex was the most sensitive to heliquinomycin; this suggests that MCM helicase is one of the main targets of heliquinomycin in vivo. It was observed that heliquinomycin did not inhibit the ATPase activity of the MCM4/6/7 complex to a great extent in the absence of single-stranded DNA. In contrast, heliquinomycin at an IC(50) value of 5.2 microM inhibited the ATPase activity of the MCM4/6/7 complex in the presence of single-stranded DNA. This suggests that heliquinomycin interferes with the interaction of the MCM4/6/7 complex with single-stranded DNA.