Pyrimidine (imatinib, dasatinib, nilotinib and pazopanib), pyridine (sorafenib) and pyrrole (sunitinib) tyrosine kinase inhibitors (TKIs) are multi-targeted TKIs with high activity towards several families of receptor and non-receptor tyrosine kinases involved in angiogenesis, tumour growth and metastatic progression of cancer. These orally administered TKIs have quite diverse characteristics with regard to absorption from the gastrointestinal tract. Absolute bioavailability in humans has been investigated only for imatinib (almost 100%) and pazopanib (14-39%; n = 3). On the basis of human radioactivity data, dasatinib is considered to be well absorbed after oral administration (19% and 0.1% of the total radioactivity were excreted as unchanged dasatinib in the faeces and urine, respectively). Quite low absolute bioavailability under fasted conditions is assumed for nilotinib (31%), sorafenib (50%) and sunitinib (50%). Imatinib, dasatinib and sunitinib exhibit dose-proportional increases in their area under the plasma concentration-time curve values over their therapeutic dose ranges. Less than dose-proportional increases were observed for nilotinib at doses ≥400 mg/day and for sorafenib and pazopanib at doses ≥800 mg/day. At steady state, the accumulation ratios are 1.5-2.5 (unchanged imatinib), 2.0 (nilotinib once-daily dosing), 3.4 (nilotinib twice-daily dosing), 1.2-4.5 (pazopanib), 5.7-6.4 (sorafenib) and 3.0-4.5 (sunitinib). Concomitant intake of a high-fat meal does not alter exposure to imatinib, dasatinib and sunitinib but leads to considerably increased bioavailability of nilotinib and pazopanib and decreased bioavailability of sorafenib. With the exception of pazopanib, the TKIs described here have large apparent volumes of distribution, exceeding the volume of body water by at least 4-fold. Very low penetration into the central nervous system in humans has been reported for imatinib and dasatinib, but there are currently no published human data for nilotinib, pazopanib, sorafenib or sunitinib. All TKIs that have been described are more than 90% bound to the plasma proteins: α(1)-acid glycoprotein and/or albumin. They are metabolized primarily via cytochrome P450 (CYP) 3A4, the only exception being sorafenib, for which uridine diphosphate glucuronosyltransferase 1A9 is the other main enzyme involved. Active metabolites of imatinib and sunitinib contribute to their antitumour activity. Although some patient demographics have been identified as significant co-factors that partly explain interindividual variability in exposure to TKIs, these findings have not been regarded as sufficient to recommend age-, sex-, bodyweight- or ethnicity-specific dose adjustment. Systemic exposure to imatinib, sorafenib and pazopanib increases in patients with hepatic impairment, and reduction of the initial therapeutic dose is recommended in this subpopulation. The starting dose of imatinib should also be reduced in renally impaired subjects. Because the solubility of dasatinib is pH dependent, co-administration of histami...

A pharmacokinetic/pharmacodynamic (PK/PD) study of the tyrosine kinase inhibitor sunitinib was conducted in 12 healthy volunteers using blood pressure and circulating biomarker levels as PD markers. Blood pressure was measured, and plasma concentration-time courses of sunitinib, its major metabolite SU12662, vascular endothelial growth factors VEGF-A and VEGF-C, and soluble VEGF receptor-2 (sVEGFR-2) were studied in healthy subjects receiving 50 mg of sunitinib orally for 3-5 consecutive days. Using NONMEM, PK/PD models were established that predicted changes (expressed as multiples relative to baseline values) in systolic blood pressure, diastolic blood pressure, VEGF-A level, and sVEGFR-2 level, of 1.10, 1.18, 2.24, and 0.76, respectively, for a typical subject after 4 weeks of treatment with 50 mg/day. Simulated blood pressure-time courses compare excellently with published data in patients, whereas changes in circulating biomarkers were greater in patients than simulations suggest for healthy subjects. In conclusion, the tumor-independent pharmacological response to sunitinib could be described by PK/PD models, thereby facilitating model-based investigations with antiangiogenic drugs, using blood pressure and circulating proteins as biomarkers.

Background Coagulation factor XI (FXI) contributes to the development of thrombosis but appears to play a minor role in hemostasis and is, therefore, an attractive anticoagulant drug target. Objectives To evaluate the safety, pharmacokinetic, and pharmacodynamic properties of BAY 2433334, an orally administered small molecule targeting activated FXI (FXIa), in healthy men. Patients/Methods This phase 1 study was conducted in two parts. In part 1, 70 volunteers were randomized 4:1 to receive a single oral dose of BAY 2433334 (5–150 mg as oral solution or immediate‐release tablets) or placebo. In part 2, 16 volunteers received a single oral dose of five BAY 2433334 5‐mg tablets with or without a high‐calorie breakfast in a randomized crossover study design. Adverse events, pharmacokinetic parameters, and pharmacodynamic parameters were assessed up to 72 h after drug administration. Volunteers were followed up after 7 to 14 days. Results BAY 2433334 demonstrated favorable safety and tolerability with a dose‐dependent increase in exposure and a terminal half‐life of 14.2 to 17.4 h. A high‐calorie breakfast reduced mean maximum plasma concentration and exposure by 31% and 12.4%, respectively. AY 2433334 was associated with a dose‐dependent inhibition of FXIa activity and an increase in activated partial thromboplastin time. Bleeding times in volunteers who had received BAY 2433334 were similar to those in volunteers who had received placebo. Conclusions These data indicate that BAY 2433334 is a promising development candidate for once‐daily oral anticoagulation; it is being evaluated in phase 2 dose‐finding studies in patients at risk of thrombosis.

Aim To evaluate BAY 2433334, an oral activated factor XI (FXIa) inhibitor, in volunteers. Methods Phase 1 study of healthy men at a German centre. Part A: randomized, single‐blind, multiple dose‐escalation study of BAY 2433334 (25/50/100 mg once daily [OD]) vs. placebo. Part B: similar design to Part A; evaluated BAY 2433334 25 mg twice daily. Part C: nonrandomized, open‐label study; evaluated potential interactions between BAY 2433334 (25/75 mg OD) and midazolam (7.5 mg), a CYP3A4 index substrate. Primary variables: treatment‐emergent adverse events (TEAEs; Parts A and B); area under the plasma concentration–time curve (AUC) and maximum plasma concentration of midazolam and α‐hydroxymidazolam (Part C). Study period: 18 days plus follow‐up visit. Results Parts A and B: 36 participants randomized to BAY 2433334; 12 to placebo. Part C: 48 participants assigned to BAY 2433334 plus midazolam. BAY 2433334 was well tolerated in all study parts. AUC and maximum plasma concentration of BAY 2433334 in plasma appeared dose proportional over 25–100 mg OD, with low‐to‐moderate variability in pharmacokinetic parameters. Multiple dosing caused minor‐to‐moderate accumulation and a mean terminal half‐life (15.8–17.8 h) supporting once‐daily dosing. Dose‐dependent FXIa activity inhibition and activated partial thromboplastin time prolongation were observed. BAY 2433334 appeared to have a minor effect on AUC for midazolam (ratio [90% confidence interval]: 1.1736 [1.0963–1.2564]) and α‐hydroxymidazolam (0.9864 [0.9169–1.0612]) only for BAY 2433334 75 mg OD on day 10. Conclusion Multiple dosing of BAY 2433334 in healthy volunteers was well tolerated, with a predictable pharmacokinetic/pharmacodynamic profile and no clinically relevant CYP3A4 induction or inhibition.

The orally available chymase inhibitor BAY 1142524 is currently being developed as a first-in-class treatment for left-ventricular dysfunction after myocardial infarction. Results from 3 randomized, single-center, phase 1 studies in healthy male volunteers examining the safety, tolerability, and pharmacokinetics of BAY 1142524 are summarized. In this first-in-human study, single oral doses of 1-200 mg were administered in fasted state as liquid service formulation or immediate release (IR) tablets. The relative bioavailability and the effect of a high-fat/high-calorie meal were investigated at the 5-mg dose. In a multiple-dose escalation study, doses of 5-50 mg twice daily and 100 mg once daily were given for 5 consecutive days. BAY 1142524 was safe and well tolerated and had no effects on heart rate or blood pressure compared with placebo. BAY 1142524 was absorbed with peak concentration 1-3 hours after administration for IR tablets; it was eliminated from plasma with a terminal half-life of 6.84-12.0 hours after administration of liquid service formulation or IR tablets. Plasma exposures appeared to be dose-linear, with a negligible food effect. There was only low accumulation of BAY 1142524 after multiple dosing. BAY 1142524 exhibited a pharmacokinetic profile allowing for once-daily dosing. The absence of blood pressure effects after administration of BAY 1142524 supports the combination of this novel anti-remodeling drug with existing standard of care in patients with left-ventricular dysfunction after acute myocardial infarction.