Safety, tolerability and pharmacokinetics of TAS-108, a novel anti-oestrogen, in healthy post-menopausal Japanese women: a phase I single oral dose study.

TAS-108 is a novel steroidal anti-oestrogen, expected to be useful for the treatment of breast cancer. The present study was conducted to investigate the safety, tolerability and pharmacokinetics of TAS-108 following the administration at a single oral dose of 40 mg to up to 120 mg in 12 post-menopausal women and the effect of food on the pharmacokinetics of the drug. All adverse events were mild and involved transient symptoms that resolved without therapeutic intervention. TAS-108 was readily absorbed and plasma levels of TAS-108 steadily declined, apparently in a multi-exponential manner. C(max) and AUC(0-12) were proportionally increased with increasing dose of TAS-108. The C(max) and AUC(0-t) of TAS-108 and its metabolite, deEt-TAS-108, were significantly increased to approximately 150% when TAS-108 was administered after a meal. Food did not affect the elimination half-life of TAS-108 or its metabolites. In this escalating dose-study of TAS-108, the drug was well tolerated by healthy post-menopausal Japanese women. The pharmacokinetics of TAS-108 indicated dose proportionality, and its bioavailability was significantly increased by food intake.

Pharmacodynamics and pharmacokinetics of AMG 531, a thrombopoiesis-stimulating peptibody, in healthy Japanese subjects: a randomized, placebo-controlled study.

AMG 531 is a novel thrombopoiesis-stimulating peptibody being investigated for the treatment of chronic immune thrombocytopenic purpura. This double-blind, phase I study evaluated the safety, pharmacodynamics, and pharmacokinetics of AMG 531 in healthy Japanese men. Thirty subjects were randomly assigned 4:1 (AMG 531/placebo) to receive 1 dose of AMG 531 (0.3, 1, or 2 microg/kg) or placebo by subcutaneous injection; subjects were evaluated for 6 weeks. AMG 531 was generally well tolerated, with adverse events similar to placebo. Treatment-related adverse events (headache, "feeling hot," malaise) were reported for 5 of 24 AMG 531-treated subjects. Platelets generated after exposure to AMG 531 functioned normally. Four of 8 subjects receiving 1 microg/kg and 7 of 8 receiving 2 microg/kg had platelet count increases > or =1.5-fold over baseline, an effect similar to that seen in non-Japanese subjects. Serum AMG 531 concentrations were below the lower limit of quantification in all but 2 subjects receiving 2 microg/kg.

Comparison of maximum drug concentration and area under the time-concentration curve between humans and animals for oral and intravenous investigational drugs.

The study compared maximum drug concentration (C(max)) and area under the time-concentration curve (AUC) after normalization of doses to body weight and to body surface area and developed relationships for C(max) and AUC between humans and animals for 75 oral and 10 intravenous investigational drugs. For the oral drugs, animal-human ratios of C(max) were different among animals in both normalizations. Surface area-normalized AUC ratios were not different, whereas weight-normalized ones were different. For both normalizations for intravenous drugs, AUC ratios were not different. Drugs exhibiting 1/10 or smaller ratios tended to have low bioavailability. Regression of the relationships for dose-normalized C(max) and AUC transformed logarithmically between humans and animals were significant for the drugs with relatively high bioavailability. As approaches for predicting human C(max) and AUC from animals, surface area normalization seems to surpass weight normalization, and the equation obtained can be applied to drugs with high bioavailability.