Evaluation of the effects of an oral notch inhibitor, crenigacestat (LY3039478), on QT interval, and bioavailability studies conducted in healthy subjects.

PURPOSE: Crenigacestat (LY3039478) is a Notch inhibitor currently being investigated in advanced cancer patients. Conducting clinical pharmacology studies in healthy subjects avoids nonbeneficial drug exposures in cancer patients and mitigates confounding effects of disease state and concomitant medications. METHODS: Three studies were conducted in healthy subjects, assessing safety, pharmacokinetics, effect on QT interval, and relative and absolute bioavailability of crenigacestat. Crenigacestat was administered as single 25, 50, or 75 mg oral doses or as an intravenous dose of 350 µg 13C15N2H-crenigacestat. Electrocardiogram measurements, and plasma and urine samples were collected up to 48 h postdose, and safety assessments were conducted up to 14 days postdose. RESULTS AND CONCLUSIONS: Exposures were dose proportional in the 25 to 75 mg dose range and mean elimination half-life was approximately 5-6 h. The exposure achieved from the new formulated capsule was approximately 30% and 20% higher for area under the plasma concentration time curve from time zero to infinity [AUC(0-∞)] and maximum plasma concentration (Cmax), respectively, compared to the reference drug in capsule formulation. The geometric least-squares mean [90% confidence interval (CI)] absolute bioavailability of crenigacestat was 0.572 (0.532, 0.615). The regression slope (90% CI) of placebo-adjusted QTcF against crenigacestat plasma concentration was - 0.001 (- 0.006, 0.003), suggesting no significant linear association. Thirty-nine subjects completed the studies and the majority of adverse events were mild. Single oral doses of 25 to 75 mg crenigacestat and an IV dose of 350 µg 13C15N2H-crenigacestat were well tolerated in healthy subjects.

Effect of hepatic or renal impairment on the pharmacokinetics of evacetrapib.

PURPOSE: The aim of this study is to investigate the effect of hepatic or renal impairment on the pharmacokinetics of a single 130-mg evacetrapib dose. METHODS: Two open-label, parallel-design studies in males and females with normal hepatic function or Child-Pugh mild, moderate, or severe hepatic impairment, or with normal renal function or severe renal impairment. Non-compartmental pharmacokinetic parameters were estimated from plasma concentration-time data. Evacetrapib safety and tolerability were assessed. RESULTS: Pharmacokinetic parameter estimates were comparable between controls and mildly hepatically impaired subjects. Geometric mean area under the concentration-time curve (AUC) was greater, half-life (t1/2) was longer, and maximum concentration (Cmax) was lower in subjects with moderate and severe hepatic impairment than in controls. Apparent clearance (CL/F) did not differ between controls and those with mild hepatic impairment, but CL/F decreased for moderate and severe impairment. Spearman correlation coefficient showed no relationship between CL/F and Child-Pugh score. In the renal study, AUC and t1/2 were similar between groups, while Cmax was 15 % lower in subjects with severe impairment. CL/F in severely renally impaired subjects differed by <6 % from that in controls. Spearman correlation coefficient showed no apparent relationship between CL/F and estimated creatinine clearance or glomerular filtration rate. Neither study noted changes in clinical laboratory parameters or clinically significant findings. Adverse event incidence was low, and all were mild or moderate in severity. CONCLUSION: Evacetrapib exposure did not differ between mild hepatic impairment and normal hepatic function, but increased along the progression from mild to moderate to severe hepatic impairment. Severe renal impairment did not affect evacetrapib exposure.

Absolute bioavailability of evacetrapib in healthy subjects determined by simultaneous administration of oral evacetrapib and intravenous [(13) C8 ]-evacetrapib as a tracer.

This open-label, single-period study in healthy subjects estimated evacetrapib absolute bioavailability following simultaneous administration of a 130-mg evacetrapib oral dose and 4-h intravenous (IV) infusion of 175 µg [(13) C8 ]-evacetrapib as a tracer. Plasma samples collected through 168 h were analyzed for evacetrapib and [(13) C8 ]-evacetrapib using high-performance liquid chromatography/tandem mass spectrometry. Pharmacokinetic parameter estimates following oral and IV doses, including area under the concentration-time curve (AUC) from zero to infinity (AUC[0-∞]) and to the last measureable concentration (AUC[0-tlast ]), were calculated. Bioavailability was calculated as the ratio of least-squares geometric mean of dose-normalized AUC (oral : IV) and corresponding 90% confidence interval (CI). Bioavailability of evacetrapib was 44.8% (90% CI: 42.2-47.6%) for AUC(0-∞) and 44.3% (90% CI: 41.8-46.9%) for AUC(0-tlast ). Evacetrapib was well tolerated with no reports of clinically significant safety assessment findings. This is among the first studies to estimate absolute bioavailability using simultaneous administration of an unlabeled oral dose with a (13) C-labeled IV microdose tracer at about 1/1000(th) the oral dose, with measurement in the pg/mL range. This approach is beneficial for poorly soluble drugs, does not require additional toxicology studies, does not change oral dose pharmacokinetics, and ultimately gives researchers another tool to evaluate absolute bioavailability.